2019 |
Mehlich F, Roberts AE, Kerscher M, Comba P, Lawrance GA, Wuertele C, et al., 'Synthesis and characterization of copper complexes with a series of tripodal amine ligands', INORGANICA CHIMICA ACTA, 486 742-749 (2019) [C1]
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Nova |
2018 |
Napitupulu M, Walanda DK, Lawrance GA, Maeder M, 'Phosphate ester hydrolysis promoted by an amidopyridine carboxylate complex', Rasayan Journal of Chemistry, 11 894-903 (2018) [C1]
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Nova |
2017 |
Lawrance G, Palmer DH, 'A Comparative Analysis of Teacher Education by Country', Global Journal of Educational Studies, 3 105-117 (2017) [C1]
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Nova |
2015 |
Tidey JP, Oconnor AE, Markevich A, Bichoutskaia E, Cavan JJP, Lawrance GA, et al., 'Epitaxial retrieval of a disappearing polymorph', Crystal Growth and Design, 15 115-123 (2015) [C1]
Recrystallization of [PdCl2([9]aneS2O)] ([9]aneS2O = 1-oxa-4,7-dithiacyclononane), 1, and [PtCl2([9]aneS2O)], 2, by diffusion of Et2O vapor into solutions of the complexes in MeNO... [more]
Recrystallization of [PdCl2([9]aneS2O)] ([9]aneS2O = 1-oxa-4,7-dithiacyclononane), 1, and [PtCl2([9]aneS2O)], 2, by diffusion of Et2O vapor into solutions of the complexes in MeNO2 yielded three phases of 1 and two phases of 2. The known phase of 1, herein designated a-1, was obtained under ambient conditions. A second phase, designated ß-1, was initially also obtained by this method; however, following the advent of a third phase, ¿-1, all subsequent efforts over a period of a year to crystallize ß-1 yielded either ¿-1, obtained by carrying out the recrystallization at elevated temperature, or a-1, commonly found throughout the study. This persistent absence of a phase which could initially be crystallized with ease led us to the conclusion that ß-1 was an example of a "disappearing polymorph". The first phase obtained of 2, designated a-2, was obtained by recrystallization under ambient conditions and is isomorphous and isostructural with a-1. The second phase ß-2 was obtained by slight elevation of the recrystallization temperature and was found to be isomorphous and isostructural with ß-1. Subsequently, ß-2 was used to seed the growth of the disappearing polymorph ß-1. No third phase of 2 (¿-2) has been isolated thus far.
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Nova |
2013 |
Conway W, Wang X, Fernandes D, Burns R, Lawrance G, Puxty G, Maeder M, 'Toward the Understanding of Chemical Absorption Processes for Post-Combustion Capture of Carbon Dioxide: Electronic and Steric Considerations from the Kinetics of Reactions of CO2(aq) with Sterically hindered Amines', ENVIRONMENTAL SCIENCE & TECHNOLOGY, 47 1163-1169 (2013) [C1]
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Nova |
2013 |
Conway W, Fernandes D, Beyad Y, Burns R, Lawrance G, Puxty G, Maeder M, 'Reactions of CO2 with Aqueous Piperazine Solutions: Formation and Decomposition of Mono- and Dicarbamic Acids/Carbamates of Piperazine at 25.0 degrees C', JOURNAL OF PHYSICAL CHEMISTRY A, 117 806-813 (2013) [C1]
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Nova |
2013 |
Zhang J, Luo S-X, McCluskey A, Lawrance GA, 'Metal-Templated Macrocycle Synthesis in an Ionic Liquid: A Comparison With Reaction in Protic Solvents', Synthesis and Reactivity in Inorganic, Metal Organic, and Nano Metal Chemistry, 43 1-5 (2013) [C1]
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Nova |
2012 |
Conway WO, Wang X, Fernandes D, Burns RC, Lawrance GA, Puxty G, Maeder M, 'Toward rational design of amine solutions for PCC applications: The kinetics of the reaction of CO 2(aq) with cyclic and secondary amines in aqueous solution', Environmental Science and Technology, 46 7422-7429 (2012) [C1]
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Nova |
2012 |
Fernandes D, Conway WO, Wang X, Burns RC, Lawrance GA, Maeder M, Puxty G, 'Protonation constants and thermodynamic properties of amines for post combustion capture of CO2', Journal of Chemical Thermodynamics, 51 97-102 (2012) [C1]
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Nova |
2012 |
Fernandes D, Conway WO, Burns RC, Lawrance GA, Maeder M, Puxty G, 'Investigations of primary and secondary amine carbamate stability by 1H NMR spectroscopy for post combustion capture of carbon dioxide', Journal of Chemical Thermodynamics, 54 183-191 (2012) [C1]
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Nova |
2011 |
Hakimi M, Maeder M, Lawrance GA, 'Synthesis, characterization, and crystal structure of a tricadmium complex of 3,4-diamino-5-methyl-1,2,4-triazole', Journal of Coordination Chemistry, 64 105-114 (2011) [C1]
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Nova |
2011 |
Tiwow V, Lawrance GA, Maeder M, Jensen P, 'Complexation of the N,N',O-donor ligand N-trans-(2'-hydroxycyclohexyl)-2-aminomethylpyridine', Journal of Coordination Chemistry, 64 3637-3651 (2011) [C1]
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Nova |
2011 |
Wang X, Conway WO, Fernandes D, Lawrance GA, Burns RC, Puxty G, Maeder M, 'Kinetics of the reversible reaction of CO2(aq) with ammonia in aqueous solution', Journal of Physical Chemistry A, 115 6405-6412 (2011) [C1]
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Nova |
2011 |
Conway WO, Wang X, Fernandes D, Burns RC, Lawrance GA, Puxty G, Maeder M, 'Comprehensive kinetic and thermodynamic study of the reactions of CO(2)(aq) and HCO(3)(-) with monoethanolamine (MEA) in aqueous solution', Journal of Physical Chemistry A, 115 14340-14349 (2011) [C1]
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Nova |
2011 |
Li X-M, Fan F, Lu J-S, Xue S-F, Zhang Y-Q, Zhu Q-J, et al., 'Host-guest complexes of cucurbit[8]uril with some pentaerythritol derivative guests', New Journal of Chemistry, 35 1088-1095 (2011) [C1]
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Nova |
2010 |
Zuo S-H, Zhao H-L, Zhang L-F, Yuan H-H, Lan M-B, Lawrance GA, Wei G, 'An amperometric biosensor based on glucose oxidase immobilized in a sol-gel polyvinyl alcohol/silica hybrid composite film on a prussian blue modified electrode', Advanced Science Letters, 3 476-481 (2010) [C1]
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Nova |
2010 |
Clifford SE, Lawrance GA, Neuhold Y-M, Maeder M, 'Conjoint analysis of kinetic and equilibrium data for mechanistic elucidation in polynuclear complexation reactions, exemplified by metal(II) helicate complex formation', Australian Journal of Chemistry, 63 141-144 (2010) [C1]
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Nova |
2010 |
Angus-Dunne S, Burns RC, Craig DC, Lawrance GA, 'Synthesis and crystal structure of the palladium(IV) polyoxomolybdate, K0.75Na3.75[PdMo6O24H3.5] 17H2O', Zeitschrift fuer Anorganische und Allgemeine Chemie, 636 727-734 (2010) [C1]
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Nova |
2010 |
Luo S-X, Tiwow VMA, Maeder M, Lawrance GA, 'Synthesis and metal(II) ion complexation of pyridine-2, 6-diamides incorporating amino alcohols', Journal of Coordination Chemistry, 63 2400-2418 (2010) [C1]
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Nova |
2009 |
Zuo S, Wu X, Teng Y, Yuan H, Lan M, Lawrance GA, Wei G, 'Direct electron transfer of glucose oxidase immobilized on a mesoporous silica KIT-6 matrix to screen-printed electrodes', Journal of Nanoscience and Nanotechnology, 9 4767-4773 (2009) [C1]
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Nova |
2009 |
Walanda DK, Lawrance GA, Donne SW, 'Kinetics of Mn2O3 digestion in H2SO4 solutions', Journal of Solid State Chemistry, 182 1336-1342 (2009) [C1]
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Nova |
2009 |
Zuo S-H, Zhang L-F, Yuan H-H, Lan M-B, Lawrance GA, Wei G, 'Electrochemical detection of DNA hybridization by using a zirconia modified renewable carbon paste electrode', Bioelectrochemistry, 74 223-226 (2009) [C1]
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Nova |
2009 |
McCann N, Phan DT, Attalla M, Puxty G, Fernandes D, Conway WO, et al., 'Molecular interactions between amine and carbonate species in aqueous solution: Kinetics and thermodynamics', Energy Procedia, 1 995-1002 (2009) [C1]
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Nova |
2009 |
Clifford SE, Tiwow VMA, Gendron A, Maeder M, Rossignoli M, Lawrance GA, et al., 'Complexation of constrained ligands piperazine, N-substituted piperazines, and thiomorpholine', Australian Journal of Chemistry, 62 1196-1206 (2009) [C1]
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Nova |
2009 |
Napitupulu M, Griggs BL, Luo S-X, Turner P, Maeder M, Lawrance GA, 'Symmetrical diamides based on 2,6-bis(methoxycarbonyl)pyridine: Syntheses and metal Ion binding studies', Journal of Heterocyclic Chemistry, 46 243-250 (2009) [C1]
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Nova |
2009 |
Whitehead JA, Zhang J, McCluskey A, Lawrance GA, 'Comparative leaching of a sulfidic gold ore in ionic liquid and aqueous acid with thiourea and halides using Fe(III) or HSO5- oxidant', Hydrometallurgy, 98 276-280 (2009) [C1]
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Nova |
2008 |
Feng Y, Xiao X, Xue S-F, Zhang Y-Q, Zhu Q-J, Tao Z, et al., 'Host-guest complex of a water-soluble cucurbit[6]uril derivative with the hydrochloride salt of 3-amino-5-phenylpyrazole', Supramolecular Chemistry, 20 517-525 (2008) [C1]
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Nova |
2008 |
Zhang J, Lawrance GA, Chau N, Robinson PJ, McCluskey A, 'From Spanish fly to room-temperature ionic liquids (RTILs): Synthesis, thermal stability and inhibition of dynamin 1 GTPase by a novel class of RTILs', New Journal of Chemistry, 32 28-36 (2008) [C1]
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Nova |
2008 |
Xiao X, Tao Z, Xue SF, Zhu QJ, Zhang JX, Lawrance GA, et al., 'Interaction between cucurbit[8]uril and viologen derivatives', Journal of Inclusion Phenomena and Macrocyclic Chemistry, 61 131-138 (2008) [C1]
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Nova |
2008 |
Comba P, Kerscher M, Lawrance GA, Martin B, Wadepohl H, Wunderlich S, 'Stable five- and six-coordinate cobalt (III) complexes with a pentadentate bispidine ligand', Angewandte Chemie-International Edition, 47 4740-4743 (2008) [C1]
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Nova |
2008 |
Clegg JK, Bray DJ, Gloe K, Gloe K, Jolliffe KA, Lawrance GA, et al., 'Synthetic, structural, electrochemical and solvent extraction studies of neutral trinuclear Co(ii), Ni(ii), Cu(ii) and Zn(ii) metallocycles and tetrahedral tetranuclear Fe(iii) species incorporating 1,4-aryl-linked bis-b-diketonato ligands', Dalton Transactions, 1331-1340 (2008) [C1]
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Nova |
2008 |
Zuo S-H, Zhang L-F, Zhao Y-H, Yuan H-H, Lan M-B, Lawrance GA, Wei G, 'Electrochemical detection of short DNA sequences related to the Escherichia coli pathogen using a zirconia-modified screen-printed DNA biosensor', Australian Journal of Chemistry, 61 962-967 (2008) [C1]
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Nova |
2007 |
Farrah HE, Lawrance GA, Wanless EJ, 'Solubility of calcium sulfate salts in acidic manganese sulfate solutions from 30 to 105 degrees C', Hydrometallurgy, 86 13-21 (2007) [C1]
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2007 |
Whitehead JA, Zhang J, Pereira N, McCluskey A, Lawrance GA, 'Application of 1-alkyl-3-methyl-imidazolium ionic liquids in the oxidative leaching of sulphidic copper, gold and silver ores', Hydrometallurgy, 88 109-120 (2007) [C1]
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2007 |
Napitupulu M, Rossignoli M, Lawrance GA, Maeder M, Turner P, 'Cyclic polyamines via a molybdenum(0) templated Mannich-type reaction', Transition Metal Chemistry, 32 287-291 (2007) [C1]
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Nova |
2007 |
Cong H, Tao LL, Yu YH, Tao Z, Yang F, Zhao YJ, et al., 'Interaction between tetramethylcucurbit[6]uril and some pyridine derivates', Journal of Physical Chemistry A, 111 2715-2721 (2007) [C1]
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Nova |
2007 |
Clegg JK, Bray DJ, Gloe K, Gloe K, Hayter MJ, Jolliffe KA, et al., 'Neutral (bis-B-diketonato) iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) metallocycles: structural, electrochemical and solvent extraction studies', Dalton Transactions, 1719-1730 (2007) [C1]
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2007 |
Owen MP, Lawrance GA, Donne SW, 'An electrochemical quartz crystal microbalance study into the deposition of manganese dioxide', Electrochimica Acta, 52 4630-4639 (2007) [C1]
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Nova |
2007 |
McCann N, Lawrance GA, Neuhold Y-M, Maeder M, 'Complexation kinetics of copper(II) and nickel(II) with macrocycles: Identification of an outer-sphere chelate effect', Inorganic Chemistry, 46 4002-4009 (2007) [C1]
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Nova |
2007 |
Born K, Comba P, Ferrari R, Lawrance GA, Wadepohl H, 'Stability constants: A new twist in transition metal bispidine chemistry', Inorganic Chemistry, 46 458-464 (2007) [C1]
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Nova |
2007 |
Griggs BL, Lawrance GA, Maeder M, Robertson MJ, Turner P, 'Aminoalcohols incorporating piperazine ring: Synthesis, complexation of a hexadentate ligand and DNA cleavage capability of copper(II) complexes', Inorganica Chimica Acta, 360 2403-2410 (2007) [C1]
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Nova |
2007 |
Bernhardt PV, Lawrance GA, Skelton BW, White AH, 'Isolation and structural characterization of Di- And tetra-protonated forms of the macrocyclic hexaamine trans-6,13-Dimethyl-1,4,8-11-tetraazacyclodecane- 6,13-diamine', Zeitschrift fur Anorganische und Allgemeine Chemie, 633 1036-1039 (2007) [C1]
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Nova |
2006 |
Angus-Dunne SJ, Lee Chin LEP, Burns RC, Lawrance GA, 'Metallocene and organo-main group trifluoromethanesulfonates', Transition Metal Chemistry, 31 268-275 (2006) [C1]
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Nova |
2006 |
McCann N, De Iuliis GN, Lawrance GA, Maeder M, Schrader K, Moore P, 'Mono- and dinuclear copper(II) complexes of pendant-arm macrocyclic polyamines: Synthesis, characterization and investigation as hydrolytic cleavage agents for DNA', Inorganic Reaction Mechanisms, 6 91-112 (2006) [C1]
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Nova |
2006 |
Napitupulu M, Lawrance GA, Clarkson GJ, Moore P, 'Methyl 2-[N-(2'-Pyridylmethyl)carbamyl]pyridine-6-carboxylate: A precursor for unsymmetrical diamide ligands', Australian Journal of Chemistry, 59 796-804 (2006) [C1]
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Nova |
2005 |
Lawrance GA, Maeder M, Napitupulu M, Nolan AL, Rossignoli M, Tiwow VMA, Turner P, 'Palladium(II) as a versatile template for the formation of tetraaza macrocycles via Mannich-type reactions', Inorganica Chimica Acta, 358 3227-3235 (2005) [C1]
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Nova |
2005 |
Lin X, Burns RC, Lawrance GA, 'Heavy metals in wastewater: The effect of electrolyte composition on the precipitation of cadmium(II) using lime and magnesia', Water Air and Soil Pollution, 165 131-152 (2005) [C1]
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Nova |
2005 |
Walanda DK, Lawrance GA, Donne SW, 'Hydrothermal MnO2: synthesis, structure, morphology and discharge performance', Journal of Power Sources, 139 325-341 (2005) [C1]
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2005 |
Nolan AL, Irwin JA, Burns RC, Lawrance GA, 'Reaction kinetics and mechanism of formation of MnW6O24 (8-) by hypochlorous acid oxidation of Mn(II)(aq) in the presence of tungstate', Inorganic Reaction Mechanisms, 5 181-195 (2005) [C1]
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2005 |
Alcock NW, Clarkson G, Glover PB, Lawrance GA, Moore P, Napitupulu M, 'Complexes of 2,6-bis N-(2 '-pyridylmethyl)carbamy pyridine: formation of mononuclear complexes, and self-assembly of double helical dinuclear and tetranuclear copper(II) and trinuclear nickel(II) complexes', Dalton Transactions, 518-527 (2005) [C1]
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Nova |
2005 |
Nuber B, Pritzkow H, Bleiholder C, Borzel H, Comba P, Ferrari R, et al., 'Coordination chemistry of a new rigid, hexadentate bispidine-based bis(amine)tetrakis(pyridine) ligand', Inorganic Chemistry, 44 8145-8155 (2005) [C1]
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Nova |
2004 |
Alcock NW, Clarkson GJ, Lawrance GA, Moore P, 'Metal-Mediated Pseudo Coordination Isomerism in Complexes of Mixed Neutral Didentate and Dianionic Tridentate Pyridine-Containing Ligands', Australian Journal of Chemistry, 57 565-570 (2004) [C1]
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Nova |
2004 |
Robertson MJ, Lawrance GA, Maeder M, Turner P, 'Octahedral Complexes of a Mixed N,N,O-Donor Ligand N-trans-(2?-hydroxycyclohexyl)-2-aminomethylpyridine', Australian Journal of Chemistry, 57 483-490 (2004) [C1]
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Nova |
2004 |
Whitehead JA, Lawrance GA, McCluskey A, 'Analysis of Gold in Solutions Containing Ionic Liquids by Inductively Coupled Plasma Atomic Emission Spectometry', Australian Journal of Chemistry, 57 151-155 (2004) [C1]
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Nova |
2004 |
Robertson MJ, De Iuliis GN, Maeder M, Lawrance GA, 'Metal-directed synthesis of a chiral acyclic pentaamine and pendant-arm macrocyclic hexaamine derived from an amino acid', Inorganica Chimica Acta, 357 557-570 (2004) [C1]
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2004 |
Farrah HE, Lawrance GA, Wanless EJ, 'Gypsum-anhydrite transformation in hot acidic manganese sulfate solution. A comparative kinetic study employing several analytical methods', Hydrometallurgy, 75 91-98 (2004) [C1]
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2004 |
Lawrance GA, Maeder M, Robertson MJ, Sutrisno, 'Synthesis of a four-strand N202-donor ligand and its transition metal complexation probed by electrospray ionisation mass spectrometry', Transitional Metal Chemistry, 29 505-510 (2004) [C1]
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Nova |
2004 |
Dahal MP, Lawrance GA, 'Oxidation of Iodide and Other Inorganic Ions Employing Nonomolybdomanganate Ion ([MnMo9O32]6-) as Oxidant', Inorganic Reaction Mechanisms, 5 117-124 (2004) [C2]
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2004 |
Lavalette A, Lawrance GA, Alcock NW, Hannon MJ, 'Channel Structures in a Simple Inorganic Salt - An Open Framework Formed through Structural Integration of Distinct Sodium Acetate and Sodium Perchlorate Domains', European Journal of Inorganic Chemistry, 3981-3983 (2004) [C1]
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Nova |
2004 |
Whitehead JA, Lawrance GA, McCluskey A, ''Green' leaching: recyclable and selective leaching of gold-bearing ore in an ionic liquid', Green Chemistry, 6 313-315 (2004) [C1]
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Nova |
2003 |
Nolan AL, Baltpurvins K, Hamilton IC, Lawrance GA, 'Chemostat-controlled selective leaches of model soil phases - the hydrous manganese and iron oxides. Part 1', Geochemistry: Exploration, Environment, Analysis, 3 157-168 (2003) [C1]
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2003 |
Nolan AL, Baltpurvins K, Hamilton IC, Lawrance GA, 'Chemostat-controlled selective leaches of model soil phases - the hydrous manganese and iron oxides. Part 2: Re-adsorption studies', Geochemistry: Exploration, Environment, Analysis, 3 313-320 (2003) [C1]
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2003 |
Comba P, De Iuliis GN, Lawrance GA, Luther S, Maeder M, Nolan AL, et al., 'Geometrical isomerism in octahedral complexes arising from the presence of a fused ring on a triaza macrocycle', Dalton Transactions, 2188-2193 (2003) [C1]
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2003 |
Dong Y, Lawrance GA, Lindoy LF, Turner P, 'Macrocyclic ligand design: Interaction of a series of successively N-benzylated derivatives of 1,4,8,11-tetraazacyclotetradecane (cyclam) with copper(II) and nickel(II)', Dalton Transactions, - 1567-1576 (2003) [C1]
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2003 |
Bernhardt P, Hambley T, Lawrance GA, Maeder M, Wilkes EN, 'Isomers of 1,4,8, 11-tetraazacyclotetradecane-6, 13-dicarboxylate characterized as cobalt(lll) complexes', Australian Journal of Chemistry, 56 679-684 (2003) [C1]
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Nova |
2003 |
Lin X, Burns RC, Lawrance GA, 'Effect of Cadmium(II) and Anion Type on the Ageing of Ferrihydrite and its Subsequent Leaching under Neutral and Alkaline Conditions', Water, Air and Soil Pollution, 143 155-177 (2003) [C1]
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2003 |
De Iuliis GN, Lawrance GA, Bernhardt PV, 'DNA cleavage with dinuclear metal complexes of ligands with varying flexibility', Journal of Inorganic Biochemistry, 96 158 (2003) [C3]
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2003 |
Baran Y, Bayada A, Lawrance GA, Lye PG, Maeder M, Wilkes EN, 'Comparative stability constants for metal ions with tetraazamacrocycles of various ring sizes carrying a single amine or carboxylate pendant group', Transition Metal Chemistry, 460-463 (2003) [C1]
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2003 |
Lawrance GA, Maeder M, Robertson MJ, 'A macrocycle with two cyclohexane rings fused to a 1,4-diaza-7-oxa-cyclononane core', Heterocyclic Communication, 9 19-22 (2003) [C1]
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2002 |
Lawrance GA, Robertson MJ, Sutrisno, Von Nagy-Felsobuki EI, 'Complexation of a four-strand tetraalcohol with labile metal ions probed by electrospray mass spectrometry', Inorganica Chimica Acta, 328(1) 159-168 (2002) [C1]
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Nova |
2002 |
Baran Y, Lawrance GA, 'Base hydrolysis kinetics of cobalt(III) spiro-octaamine dimer', Turkish Journal of Chemistry, 26 771-776 (2002) [C1]
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2002 |
De Iuliis GN, Lawrance GA, Wilson N, 'Metal complex-promoted cleavage of RNA dimers and trimers; electrospray ionisation mass spectrometry evidence for cleavage', Inorganic Reaction Mechanisms, 4 169-186 (2002) [C1]
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Nova |
2002 |
Baran Y, Comba P, Lawrance GA, 'Trends in base hydrolysis rates of chlorocobalt(III) complexes of a series of related pentaamine ligands', Inorganic Reaction Mechanisms, 4 31-47 (2002) [C1]
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2002 |
Lawrance GA, Maeder M, Neuhold Y-M, Szacilowski K, Barbieri A, Stasicka Z, 'An electrospray ionization mass spectrometry study of the nitroprusside-cation-thiolate system', Dalton Transactions, -- 3649-3655 (2002) [C1]
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2002 |
Nolan AL, Burns RC, Lawrance GA, 'Kinetics and mechanism of the oxidation of Mn(II)aq by bromate and peroxomonosulfate in the presence of molybdate to form [MnIVMo9O32]6-', Journal of the Chemical Society - Dalton Transactions, 3065-3073 (2002) [C1]
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2002 |
Wei G, Hambley T, Lawrance GA, Maeder M, 'Synthesis and complexation of a chiral sexidentate pendant-arm macropolycyclic polyamino acid', Australian Journal of Chemistry, 55 667-673 (2002) [C1]
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Nova |
2001 |
Urfer A, Lawrance GA, Swinkels JA, 'The role of particle size in cathode optimization in alkaline primary batteries', Journal of Applied Electrochemistry, 31 341-347 (2001) [C1]
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2001 |
McCluskey A, Lawrance GA, Owen M, Hamilton IC, 'Ionic liquids: From green chemistry to ore refining.', ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 221 U584-U584 (2001)
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2001 |
Baran Y, Kau PMH, Lawrance GA, Sutrisno, Von Nagy-Felsobuki EI, 'Interactions of the Aminoglycoside Neamine and 2-Deoxystreptamine with Copper (II) and Zinc(II)', Inorganic Reaction Mechanisms, 3 31-38 (2001) [C1]
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2001 |
Sutrisno, Baran Y, Lawrance GA, Von Nagy-Felsobuki EI, 'Determination of acid dissociation constants of neamine by potentiometric and electrospray mass spectral techniques', Structural Chemistry, 12, No. 2 189-195 (2001) [C1]
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2001 |
Lye PG, Lawrance GA, Maeder M, 'Formation kinetics of pendant arm polyamine macrocycles with copper (II)', Journal of the Chemical Society-Dalton Transactions, 2001 2376-2382 (2001) [C1]
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2000 |
Wilkes LM, Hambley TW, Lawrance GA, Maeder M, 'Characterization of the minor cis isomer of a dipendant polyamino acid macrocycle as a dimeric nickel(II) complex', AUSTRALIAN JOURNAL OF CHEMISTRY, 53 517-521 (2000) [C1]
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2000 |
Nolan AL, Allen CC, Burns RC, Craig DC, Lawrance GA, 'X-ray structural studies of K6[CoIIW12040].~16H20 and K5[CoIIIW12O40].~16H2O and structural trends along the [XW12O40]n- series, where X=P(V), Si(IV), Co(III) and Co(II)', AUSTRALIAN JOURNAL OF CHEMISTRY, 53 59-66 (2000) [C1] |
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2000 |
Nolan AL, Allen CC, Burns RC, Craig DC, Lawrance GA, 'X-ray structural studies of K-6[(CoW12O40)-W-II]center dot similar to 16H(2)O and K-5[(CoW12O40)-W-III]center dot similar to 16H(2)O and structural trends along the [XW12O40](n-) series, where X = P-V, Si-IV, Co-III and Co-II', AUSTRALIAN JOURNAL OF CHEMISTRY, 53 59-66 (2000)
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2000 |
Nolan AL, Allen CC, Burns RC, Craig DC, Lawrance GA, 'X-ray structural studies of K
The X-ray crystal structures of K6[CoIIW12O40]·~16H 2O and K5[CoIIIW12O40]·~16H 2O are reported. The compounds are isostructural, hexagonal, space group P6222, and have Z 3 with a... [more]
The X-ray crystal structures of K6[CoIIW12O40]·~16H 2O and K5[CoIIIW12O40]·~16H 2O are reported. The compounds are isostructural, hexagonal, space group P6222, and have Z 3 with a 19.118(7), c 12.383(9) Å, V 3919.6(35) Å3, and a 19.111(2), c 12.509(2) Å, V 3956.6(9) Å3, respectively. Both anions exhibit the standard a-Keggin structure, which consists of a central tetrahedrally coordinated CoII or CoIII, surrounded by four groups of three edge-sharing octahedra (W3O13 subunits) which are linked in turn to each other and to the central CoO4 tetrahedron by shared oxygen atoms at the vertices. Although thermogravimetric analyses show that there are c. 16 water molecules per formula unit in both compounds, only six and three water molecules for the CoII and CoIII compounds, respectively, could be crystallographically located. The others are presumably zeolitic and highly disordered in nature. Structural differences between the anions on replacement of CoII by CoIII, as well as comparisons with the related [PW12O40]3- and [SiW12O40]4- ions, which contain (formally) PV and SiIV, respectively, are discussed. This comparison indicates that the W3O13 subunits become progressively more isolated with increasing size of the central heteroatom from PV to CoII, while the bonding within an individual W3O13 subunit becomes weaker. Extended-Hückel molecular orbital calculations are used to examine stability changes in the polyoxotungstate framework, using the actual polyoxotungstate geometries of the anions, on variation in size of the central heteroatom. These are compared to that in the [H3W12O40]5- ion, which has two centrally located H+ ions, but no steric effects. The studies show that no major changes occur in the overall stability of the framework, but that there is a redistribution in the contributions of the two types of bridging oxygen atoms to the stability of the framework, which parallels the progressive isolation and weaker bonding in the W3O13 subunits. © CSIRO 2000.
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2000 |
Bernhardt PV, Lawrance GA, Luther S, Maeder M, Rossignoli M, 'Metal-directed synthesis routes to a 16-membered tetraazamacrocycle with two pendant primary amine groups', INORGANICA CHIMICA ACTA, 306 1-5 (2000) [C1]
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2000 |
Walanda DK, Burns RC, Lawrance GA, Von Nagy-Felsobuki EI, 'Unknown isopolyoxovanadate species detected by electrosspray mass spectrometry', INORGANICA CHIMICA ACTA, 305 118-126 (2000) [C1]
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2000 |
Bernhardt PV, Lawrance GA, Napitupulu M, Wei G, 'Synthesis and complexes of the sexidentate macrocycle 15-methyl-1,4,7,10,13-pentaazacyclohexadecan-15-amine', INORGANICA CHIMICA ACTA, 300-302 604-612 (2000) [C1]
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2000 |
Nolan AL, Burns RC, Lawrance GA, Craig DC, 'Octasodium hexatungstomanganate(IV) octadecahydrate', ACTA CRYSTALLOGRAPHICA C: CRYSTAL STRUCTURE COMMUNICATIONS, C56 729-730 (2000) [C1]
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2000 |
Baran Y, Lawrance GA, Martinez M, Wilkes LM, 'Comparative hydrolysis reactions of chlorocobalt(III) complexes of 13-14- and 15-membered tetrzzzamacrocycles with either an amine or carboxylate pendant group', INORGANIC REACTION MECHANISMS, 1 315-318 (2000) [C1] |
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2000 |
Walanda DK, Burns RC, Lawrance GA, Von Nagy-Felsobuki EI, 'Electrospray mass spectrometry of aqueous solutions of isopolyoxotungstates', JOURNAL OF CLUSTER SCIENCE, 11 5-28 (2000) [C1]
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2000 |
Bernhardt PV, Lawrance GA, Luther SM, Maeder M, Robertson MJ, Sutrisno, ''Tetol': a stereo-rigid four-strang motif for alkali and alkaline earth metal ion coordination', INORGANIC CHEMISTRY COMMUNICATIONS, 3 410-414 (2000) [C1]
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2000 |
De Iuliis GN, Lawrance GA, Fieuw-Makaroff S, 'Superior hydrolytic DNA cleavage by a dinuclear copper(II) N4S4-donor complex compared with a mononuclear N2S2-donor close analogue', INORGANIC CHEMISTRY COMMUNICATIONS, 3 307-309 (2000) [C1]
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Nova |
1999 |
Nolan AL, Allen CC, Burns RC, Lawrance GA, Wilkes EN, Hambley TW, 'Crystal Structure of Na9[H3W12042].24H20, a compound containing the protonated paratungstate B anion ('Acid paratungstate'), and cyclic voltammetry of acidified [H2W12042]10-solutions', Australian Journal of Chemistry, 52 955-963 (1999) [C1]
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1999 |
Dyson RM, Lawrance GA, Macke H, Maeder M, 'Stability investigations of medically relevant complexes by the simultaneous analysis of series of spectrophotometric titrations', Polyhedron, 18 3243-3251 (1999) [C1]
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1999 |
Golding SW, Hambley TW, Lawrance GA, Luther SM, Maeder M, Turner P, 'Synthesis and some octahedral complexes of a chiral triaza macrocycle', Journal of the Chemical Society-Dalton Transactions, -- 1975-1980 (1999) [C1]
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1999 |
Walanda DK, Burns RC, Lawrance GA, Von Nagy-Felsobuki EI, 'Electrospray mass spectral study of isopoloxomolybdates', Journal of the Chemical Society-Dalton Transactions, 311-321 (1999) [C1]
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1999 |
Lye PG, Lawrance GA, Maeder M, 'Complexation of pendant arm macrocycles with Cu(II) hydroxo complexes in strongly alkaline solutions. investigationof pH dependences', Inorganic Reaction Mechanisms, 1 153-159 (1999) [C1]
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1999 |
Sutrisno, Lawrance GA, Von Nagy-Felsobuki EI, 'Linear free energy relationships from collision-activated dissociation spectra: the electrospraymass spectra of transitionmetal macrocyclic complexes', European Mass Spectrometry, 5 243-252 (1999) [C1]
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1999 |
Sutrisno, Baran Y, Lawrance GA, Von Nagy-Felsobuki EI, Richens DT, Xiao H, 'Metal ion exchange in dinuclear macrocyclic complexes identified by electrospray mass spectrometry', Inorganic Chemistry Communications, 2 107-109 (1999) [C1]
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1999 |
Walanda DK, Burns RC, Lawrance GA, Von Nagy-Felsobuki EI, 'New isopolyoxovanadate ions identified by electrospray mass spectrometry', Inorganic Chemistry Communications, 2 487-489 (1999) [C1]
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1998 |
Nolan AL, Burns RC, Lawrance GA, 'Oxidation of [Co11W12O40]6- to [CoIIIW12O40]5- by peroxomonosulfate in strong and weak acid solutions, an example of zero-order kinetics', Journal of the Chemical Society - Dalton Transactions, 3041-3047 (1998) [C1]
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1998 |
Dahal MP, Lawrance GA, Maeder M, 'Kinetics of heavy metal ion adsorption onto and proton release from electrolytic manganese dioxide', Adsorption Science & Technology, 16 39-50 (1998) [C1]
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1998 |
Xiao H, Lawrance GA, Hambley TW, 'Platinum(II) template synthesis of a pendant-arm macrocycle', Australian Journal of Chemistry, 51 871-874 (1998) [C1]
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1998 |
Nolan AL, Allen CC, Burns RC, Craig D, Lawrance GA, 'Monomeric and Dimeric Cobalt(III) Polyoxomolybdates: Crystal Structures and Cyclic Voltammetry of Na3 [H6CoMo6O24].8H2O and K6 [H4Co2Mo10O38].7H2O', Australian Journal of Chemistry, 51 825-834 (1998) [C1]
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1998 |
Wei G, Lawrance GA, Richens DT, Hambley TW, Turner P, 'Copper(I) complexes of dinucleating macrobicyclic bis(dithiadiimine) ligands', Journal of the Chemical Society, Dalton Transactions, - 623-628 (1998) [C1]
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1998 |
Nu Hoai VN, Farrah HE, Lawrance GA, Orr GL, 'Efficiency of a small artificial wetland with an industrial urban catchment', The Science of the Total Environment, 214 221-237 (1998) [C1]
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1998 |
Lin X, Burns RC, Lawrance GA, 'Effect of Electrolyte Composition, and of added Iron(III) in the Presence of Selected Organic Complexing Agents, on Nickel(II) Precipitation by Lime', Water Research, 32 3637-3645 (1998) [C1]
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1997 |
Dyson RM, Kaderli S, Lawrance GA, Maeder M, Zunderbuhler AD, 'Second order global analysis: the evaluation of series of spectrophotometric titrations for improved determination of equilibrium constants', ANALYTICA CHIMICA ACTA, 353 381-393 (1997)
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1997 |
Rossignoli M, Hambley TW, Lawrance GA, Maeder M, 'A saturated heterocycle formed from ethane-1,2-diamine, formaldehyde and nitroethane: Crystal structure of 6-methyl-6-nitro-1,4-bis(2'-nitropropan-1'-yl)-1,4-diazacycloheptane', AUSTRALIAN JOURNAL OF CHEMISTRY, 50 241-245 (1997)
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1997 |
Rossignoli M, Bernhardt PV, Lawrance GA, Maeder M, 'Macrocycle formation through carbon acid-formaldehyde condensation reactions of bis(propane-1,2-diamine)- and bis (2-methylpropane-1,2-diamine)-copper(II) ions', AUSTRALIAN JOURNAL OF CHEMISTRY, 50 529-534 (1997)
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1997 |
Baran Y, Hambley TW, Lawrance GA, Wilkes EN, 'Syntheses and comparative base hydrolysis reactions of chlorocobalt(III) complexes of pendant-arm macrocyclic polyamines and polyamino acids', AUSTRALIAN JOURNAL OF CHEMISTRY, 50 883-888 (1997)
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1997 |
Donne SW, Lawrance GA, Swinkels DAJ, 'Redox processes at the manganese dioxide electrode .1. Constant-current intermittent discharge', JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 144 2949-2953 (1997)
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1997 |
Donne SW, Lawrance GA, Swinkels DAJ, 'Redox processes at the manganese dioxide electrode .2. Slow-scan cyclic voltammetry', JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 144 2954-2961 (1997)
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1997 |
Donne SW, Lawrance GA, Swinkels DAJ, 'Redox processes at the manganese dioxide electrode .3. Detection of soluble and solid intermediates during reduction', JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 144 2961-2967 (1997)
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1997 |
Baltpurvins KA, Burns RC, Lawrance GA, Stuart AD, 'Effect of Ca2+, Mg2+, and anion type on the aging of iron(III) hydroxide precipitates', ENVIRONMENTAL SCIENCE & TECHNOLOGY, 31 1024-1032 (1997)
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1997 |
Bayada A, Lawrance GA, Maeder M, 'Outer-sphere complex formation and catalysis of adenosine 5'-triphosphate hydrolysis with polyammonium cations: Kinetics employing an attenuated total reflectance infrared method', INORGANICA CHIMICA ACTA, 254 353-359 (1997)
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1997 |
Wei G, Allen CC, Hambley TW, Lawrance GA, Maeder M, 'Hydrogenolysis of a pendant alcohol dithiadiazamacrocycle. Crystal structure of the 6-amino-6-methyl-1,11-dithia-4,8-diazacyclotetradecane hydrogenolysis product as a chlorocobalt(III) complex', INORGANICA CHIMICA ACTA, 261 197-200 (1997)
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1997 |
Urfer A, Lawrance GA, Swinkels DAJ, 'Measuring variation in EMD reduction with location in primary alkaline batteries', JOURNAL OF APPLIED ELECTROCHEMISTRY, 27 667-672 (1997)
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1997 |
Baltpurvins KA, Burns RC, Lawrance GA, Stuart AD, 'Effect of electrolyte composition on zinc hydroxide precipitation by lime', WATER RESEARCH, 31 973-980 (1997)
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1997 |
Allen CC, Burns RC, Lawrance GA, Turner P, Hambley TW, 'Tetraammonium hexahydrogen-hexamolybdozincate(II) hexahydrate', ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, 53 7-9 (1997)
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1997 |
Dahal MP, Lawrance GA, Maeder M, 'Variation in the adsorption of lead(II) by a range of electrolytic manganese dioxides: Chemometric examination of correlation with physical properties', ADSORPTION SCIENCE & TECHNOLOGY, 15 583-592 (1997)
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1997 |
Baran Y, Lawrance GA, Wilkes EN, 'Comparative formation constants for metal ions with macrocycles based on 1,4,8,11-tetraazacyclotetradecane and carrying diamine, dicarboxylate or amine-carboxylate pendants', POLYHEDRON, 16 599-602 (1997)
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1997 |
Rossignoli M, Bernhardt PV, Lawrance GA, Maeder M, 'Gold(III) template synthesis of a pendant-arm macrocycle', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 323-327 (1997)
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1997 |
Rossignoli M, Bernhardt PV, Lawrance GA, 'Molybdenum carbonyl complexes of pendant-arm polyazamacrocycles', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 4247-4250 (1997)
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1996 |
Rossignoli M, Lawrance GA, Maeder M, Hockless DCR, Skelton BW, White AH, 'The influence of alkyl substituents on carbon acid formaldehyde condensation reactions of bis(alkane-1,2-diamine)copper(II) ions', AUSTRALIAN JOURNAL OF CHEMISTRY, 49 1307-1314 (1996)
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1996 |
Baltpurvins KA, Burns RC, Lawrance GA, Stuart AD, 'Effect of pH and anion type on the aging of freshly precipitated iron(III) hydroxide sludges', ENVIRONMENTAL SCIENCE & TECHNOLOGY, 30 939-944 (1996)
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1996 |
Baltpurvins KA, Burns RC, Lawrance GA, Stuart AD, 'Use of the solubility domain approach for the modeling of the hydroxide precipitation of heavy metals from wastewater', ENVIRONMENTAL SCIENCE & TECHNOLOGY, 30 1493-1499 (1996)
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1996 |
Rossignoli M, Allen CC, Hambley TW, Lawrance GA, Maeder M, '''Swollen'' macrocycles: Palladium(II)-directed template syntheses of pendant-arm 14-, 16-, and 18-membered macrocycles', INORGANIC CHEMISTRY, 35 4961-4966 (1996)
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1996 |
Hambley TW, Lawrance GA, Maeder M, Wilkes EN, 'Nickel(II) complexes of 15-membered tetraaza macrocycles with a primary amine or carboxylate pendant: Structural characterization of a one-dimensional chain compound', INORGANICA CHIMICA ACTA, 246 65-71 (1996)
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1996 |
Dahal MP, Lawrance GA, 'Adsorption of thallium(I), lead(II), copper(II), bismuth(III) and chromium(III) by electrolytic manganese dioxide', ADSORPTION SCIENCE & TECHNOLOGY, 13 231-240 (1996)
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1996 |
Wei G, Maeder M, Lawrance GA, 'Isolation of and metal ion selection by geometric isomers of a pendant-arm macrotricyclic hexaamine', POLYHEDRON, 15 3157-3162 (1996)
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1996 |
Nolan AL, Burns RC, Lawrance GA, 'Reaction kinetics and mechanism of formation of [H4Co2Mo10O38](6-) by peroxomonosulfate oxidation of Co-II in the presence of molybdate', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 2629-2636 (1996)
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1996 |
Baltpurvins KA, Burns RC, Lawrance GA, 'Heavy metals in wastewater: Modelling the hydroxide precipitation of copper(II) from wastewater using lime as the precipitant', WASTE MANAGEMENT, 16 717-725 (1996)
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1995 |
Nolan AL, Lawrence GA, Maeder M, 'Phosphorus speciation in the Williams River, New South Wales: Eutrophication and a chemometric analysis of relationships with other water quality parameters', MARINE AND FRESHWATER RESEARCH, 46 1055-1064 (1995)
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1995 |
Bayada A, Lawrance GA, Maeder M, Molloy KJ, 'ATR-IR spectroscopy for the investigation of solution reaction kinetics: Hydrolysis of trimethyl phosphate', APPLIED SPECTROSCOPY, 49 1789-1792 (1995)
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1995 |
WEI G, ALLEN CC, HAMBLEY TW, LAWRANCE GA, MAEDER M, 'METAL-DIRECTED SYNTHESIS OF DITHIA DIAZA MACROCYCLES CARRYING PENDANT ALCOHOL AND ALSO NITRO OR CARBOXYLATE GROUPS', AUSTRALIAN JOURNAL OF CHEMISTRY, 48 825-833 (1995)
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1995 |
DONNE SW, LAWRANCE GA, SWINKELS DAJ, 'THE CHEMOSTAT - A NOVEL-APPROACH TO THE SYNTHESIS OF MANGANESE-DIOXIDE', MATERIALS RESEARCH BULLETIN, 30 859-869 (1995)
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1995 |
WEI G, ALLEN CC, HAMBLEY TW, LAWRANCE GA, MAEDER M, 'METAL-DIRECTED SYNTHESES OF DITHIADIAZACYCLOTETRADECANE MACROCYCLES WITH PENDANT ALCOHOL AND NITRO OR CARBOXYLATE GROUPS INVOLVING MACROCYCLE RING EXPANSION', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 2541-2547 (1995)
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1994 |
Bottomley GA, Clark IJ, Creaser II, Engelhardt LM, Geue RJ, Hagen KS, et al., 'The synthesis and structure of encapsulating ligands: Properties of bicyclic hexamines', Australian Journal of Chemistry, 47 143-179 (1994)
Template syntheses based on tris (ethane-1, 2-diamine)cobalt(III) lead to cobalt(III) complexes of cage hexamines of the ' sarcophagine ' type ( sarcophagine = sar = 3, ... [more]
Template syntheses based on tris (ethane-1, 2-diamine)cobalt(III) lead to cobalt(III) complexes of cage hexamines of the ' sarcophagine ' type ( sarcophagine = sar = 3, 6, 10, 13, 16, 19- hexaazabicyclo [6.6.6] icosane ) rapidly and in high yield. Reduction of these species to their cobalt(II) forms enables the ligands to be removed in concentrated acids at elevated temperatures, and in hot aqueous solutions containing excess cyanide ion. The free sarcophagine and 1, 8-diaminosarcophagine [(NH2)2sar or diamsar] ligands are strong bases, accepting up to four and five protons, respectively, in aqueous solution. In chloride medium, I = 1.0, at 298 K, pK1= 11.95, pK2= 10.33, pK3= 7.17, pK4¿ 0 for sarcophagine, and pK1= 11.44, pK2= 9.64, pK3= 6.49, pK4= 5.48, pK5¿ 0 for diaminosarcophagine, with very similar values being found for triflate medium. Crystal structure determinations for both free bases, the chloride, sulfate, perchlorate and nitrate salts of diamsar, the complex of zinc chloride with sar, and the magnesium nitrate complex with diamsar show remarkably small variations in the cavity defined by the bicyclic ligands, though relatively subtle bond length and bond angle changes can be rationalized in terms of the effects of proton and metal ion binding. Exhaustive methylation of sarcophagine produces the highly lipophilic, hexatertiary base hexamethylsarcophagine, which, in the solid state, adopts quite different conformations and nitrogen-atom configurations to those of sar itself. All the ligands rapidly form metal ion complexes of generally exceptional kinetic and thermodynamic stability. © 1994 ASEG.
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1994 |
BAYADA A, LAWRANCE GA, MAEDER M, 'DIAMMONIUM SALTS DERIVED FROM 1,4-DIAZABICYCLO[2.2.2]OCTANE', AUSTRALIAN JOURNAL OF CHEMISTRY, 47 7-13 (1994)
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1994 |
BERNHARDT PV, HAMBLEY TW, LAWRANCE GA, MOLLOY KJ, 'QUINQUEDENTATE COORDINATION OF 3-[(2'-AMINO-ETHYL)AMINO]-2-[(2''-AMINOETHYL)AMINOMETHYL]PROPIONIC ACID (LH) - CRYSTAL-STRUCTURE OF TRANS-[CO(L)CL][CLO4].H2O AND MOLECULAR MECHANICS EXAMINATION OF ISOMERS', AUSTRALIAN JOURNAL OF CHEMISTRY, 47 817-827 (1994)
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1994 |
HAMBLEY TW, LAWRANCE GA, MAEDER M, MOLLOY KJ, ROSSIGNOLI M, 'COORDINATION OF 5-METHYL-3,7-DIAZANONANE-1,5,9-TRIAMINE (L) TO RHODIUM(III) - CRYSTAL-STRUCTURE OF FAC-[RH(H2L)CL3] CL(CLO4).3H2O', AUSTRALIAN JOURNAL OF CHEMISTRY, 47 829-836 (1994)
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1994 |
BERNHARDT PV, COMBA P, ELLIOTT BL, LAWRANCE GA, MAEDER M, OLEARY MA, et al., 'METAL-DIRECTED SYNTHESIS OF MACROCYCLIC TETRAAMINES WITH PENDANT NITRO OR AMINE GROUPS, BASED ON TRANS-CYCLOHEXANE-1,2-DIAMINE', AUSTRALIAN JOURNAL OF CHEMISTRY, 47 1171-1178 (1994)
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1994 |
BAYADA A, LAWRANCE GA, MAEDER M, MARTINEZ M, SKELTON BW, WHITE AH, 'OUTER-SPHERE COORDINATION OF POLYCYANOMETALLATE ANIONS WITH POLYAMMONIUM MACROCYCLES - A SPECTROPHOTOMETRIC STUDY', INORGANICA CHIMICA ACTA, 227 71-77 (1994)
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1994 |
ANGUSDUNNE SJ, BURNS RC, CRAIG DC, LAWRANCE GA, 'A NOVEL HETEROPOLYMETALATE CONTAINING PALLADIUM(II) - SYNTHESIS AND CRYSTAL-STRUCTURE OF K2NA6[PD2W10O36]CENTER-DOT-22H(2)O', JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, 523-524 (1994)
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1994 |
HAMBLEY TW, LAWRANCE GA, MAEDER M, WEI G, 'CHLOROMETAL(III) COMPLEXES OF A NEW CHIRAL QUINQUEDENTATE POLYAMINO ACID-BASED ON (SS)-TRANS-CYCLOHEXANE-1,2-DIAMINE', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 355-359 (1994)
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1994 |
LYE PG, LAWRANCE GA, MAEDER M, SKELTON BW, WEN H, WHITE AH, 'SELECTION OF METAL-IONS BY GEOMETRIC ISOMERS OF A POLYAMINE MACROCYCLE WITH PENDANT DONORS', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 793-798 (1994)
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1994 |
BAYADA A, LAWRANCE GA, MAEDER M, OLEARY MA, 'METAL-DIRECTED SYNTHESIS OF AMINOBENZYL POLYAZA MACROCYCLES - CANDIDATES FOR ATTACHMENT TO POLYMERS AND BIOMOLECULES', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 3107-3111 (1994)
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1994 |
Bayada A, Lawrance GA, Maeder M, 'A spectrophotometric method for the quantification of outer-sphere coordination: A bicyclic ammonium cation with the hexacyanocobaltate(III) anion', Supramolecular Chemistry, 3 261-266 (1994)
The outer-sphere interaction between the Co(CN)|¿anion with the two protonated forms of DABCO (l,4-diazabicydo[2.2.2]octane) was investigated by a spectrophotometric titration met... [more]
The outer-sphere interaction between the Co(CN)|¿anion with the two protonated forms of DABCO (l,4-diazabicydo[2.2.2]octane) was investigated by a spectrophotometric titration method. The resulting outer-sphere stability constant for the diprotonated DABCOH|+ cation was determined as log Kos = 2.53 ± 0.01, compared to the value of 2.77 ± 0.12 obtained using conventional potentiometric titration results. Absorption changes were very small; however, good reproducible results were obtained for the higher charged diprotonated cation interaction and the method may have general application.© 1994 Gordon and Breach Science Publishers SA
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1993 |
Lawrance GA, Maeder M, Wilkes EN, 'Metal-Directed Macrocyclization Reactions Involving Formaldehyde, Amines and Mono- Or Bi-Functional Methylene Compounds', Reviews in Inorganic Chemistry, 13 199-232 (1993)
Reactions of transition metal complexes of ligands with predominantly amine donors with formaldehyde alone, or with formaldehyde and additional reagents (ammonia, primary amines, ... [more]
Reactions of transition metal complexes of ligands with predominantly amine donors with formaldehyde alone, or with formaldehyde and additional reagents (ammonia, primary amines, and mono- or Afunctional methylene compounds) are of ten facile, and lead to new acyclic and macrocyclic molecules. Formaldehyde reacts with coordinated amines to form an imine (or aminol) which is susceptible to further nucleophilic attack by a suitably disposed group of the precursor complex or by an additional external reagent. Condensation involving two formaldehyde molecules, two cis-disposed coordinated primary amines and ammonia, an additional primary amine or a carbon acid with at least two acidic protons can generate a new six-membered chelate ring, of ten cariying additional pendant groups. These reactions are central to formation of the wide range of coordinated and largely saturated cyclic, macromonocyclic and macropolycyclic polyamine molecules reported herein. © 1993, Walter de Gruyter. All rights reserved.
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1993 |
DEARIE CM, DYSON RM, HAMBLEY TW, LAWRANCE GA, MAEDER M, TANNOCK GA, 'CRYSTAL-STRUCTURE OF A LUMINESCENT EUROPIUM(III) COMPLEX - PROBING THE ACTIVE SPECIES IN DISSOCIATION-ENHANCED LANTHANIDE FLUOROIMMUNOASSAY', AUSTRALIAN JOURNAL OF CHEMISTRY, 46 577-582 (1993)
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1993 |
ELLIOTT AJ, LAWRANCE GA, WEI G, 'METAL-DIRECTED SYNTHESIS OF A PENDENT-ARM N2S2-MACROCYCLE INCORPORATING AN ORTHO-XYLENE UNIT', POLYHEDRON, 12 851-853 (1993)
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1993 |
ELLIOTT BL, HAMBLEY TW, LAWRANCE GA, MAEDER M, WEI G, 'CHLOROCOBALT(III) AND CHLOROCHROMIUM(III) COMPLEXES OF A NEW CHIRAL QUINQUEDENTATE POLYAMINE BASED ON RR-TRANS-CYCLOHEXANE-1,2-DIAMINE', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1725-1730 (1993)
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1993 |
ANGUSDUNNE SJ, IRWIN JA, BURNS RC, LAWRANCE GA, CRAIG DC, 'REACTION-KINETICS AND MECHANISM OF FORMATION OF [MNMO9O32]6- BY HYPOCHLOROUS ACID OXIDATION OF MN2+ (AQ) IN THE PRESENCE OF MOLYBDATE', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 2717-2726 (1993)
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1992 |
LAWRANCE GA, MARTINEZ M, SKELTON BW, VANELDIK R, WHITE AH, 'QUINQUEDENTATE COORDINATION OF 10-METHYL-1,4,8,12-TETRAAZACYCLOPENTADECAN-10-AMINE (L) TO RHODIUM(III) - CRYSTAL-STRUCTURE OF CIS-[RH(L)CL][CLO4]2.H2O AND COMPARATIVE ACTIVATION VOLUMES FOR BASE HYDROLYSIS OF [M(L)CL]2+ (M=RH, CO, CR)', AUSTRALIAN JOURNAL OF CHEMISTRY, 45 351-359 (1992)
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1992 |
DUNNE SJ, BURNS RC, HAMBLEY TW, LAWRANCE GA, 'OXIDATION OF MANGANESE(II) BY PEROXOMONOSULFURIC ACID IN AQUEOUS-SOLUTION IN THE PRESENCE OF MOLYBDATE - CRYSTAL-STRUCTURE OF THE K6[MNMO9O32].6H2O PRODUCT', AUSTRALIAN JOURNAL OF CHEMISTRY, 45 685-693 (1992)
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1992 |
DUNNE SJ, BURNS RC, LAWRANCE GA, 'OXIDATION OF NICKEL(II) AND MANGANESE(II) BY PEROXODISULFATE IN AQUEOUS-SOLUTION IN THE PRESENCE OF MOLYBDATE - CRYSTAL-STRUCTURE OF THE (NH4)6[NIMO9O32].6H2O PRODUCT', AUSTRALIAN JOURNAL OF CHEMISTRY, 45 1943-1952 (1992)
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1992 |
BERNHARDT PV, LAWRANCE GA, HAMBLEY TW, 'PLATINUM(IV) COMPLEXES OF A TETRAAZA MACROCYCLE WITH PENDENT DICHLOROAMINE OR AMMONIUM GROUPS', INORGANIC CHEMISTRY, 31 631-634 (1992)
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1992 |
BERNHARDT PV, COMBA P, HAMBLEY TW, LAWRANCE GA, VARNAGY K, 'ISOLATION AND COMPLEXATION OF THE CIS ISOMER OF THE PENDANT ARM MACROCYCLE 6,13-DIMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECANE-6,13-DIAMINE', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 355-359 (1992)
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1992 |
LAWRANCE GA, MARTINEZ M, SKELTON BW, WHITE AH, 'QUINQUEDENTATE COORDINATION OF AMINO-SUBSTITUTED TETRAAZACYCLOALKANES TO CHROMIUM(III)', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 823-828 (1992)
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1992 |
HAMBLEY TW, LAWRANCE GA, MAEDER M, WILKES EN, 'SYNTHESIS OF A NEW POTENTIALLY SEXIDENTATE PENDANT-ARM MACROCYCLIC POLYAMINO ACID AND COORDINATION TO COBALT(III)', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1283-1289 (1992)
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1992 |
LAWRANCE GA, MANNING TM, MAEDER M, MARTINEZ M, OLEARY MA, PATALINGHUG WC, et al., 'QUINQUEDENTATE COORDINATION OF AMINO-SUBSTITUTED TETRAAZACYCLOALKANES TO COBALT(III) .1. COMPLEXES OF MACROCYCLES OF DIFFERING RING SIZE, AND CRYSTAL-STRUCTURES OF CIS ISOMERS', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1635-1641 (1992)
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1992 |
HAMBLEY TW, LAWRANCE GA, MARTINEZ M, SKELTON BW, WHITE AH, 'QUINQUEDENTATE COORDINATION OF AMINO-SUBSTITUTED TETRAAZACYCLOALKANES TO COBALT(III) .2. CRYSTAL-STRUCTURES OF TRANSISOMERS, MOLECULAR MECHANICS CALCULATIONS AND BASE-HYDROLYSIS KINETICS', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1643-1648 (1992)
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1992 |
LAWRANCE GA, MARTINEZ M, SKELTON BW, WHITE AH, 'QUINQUEDENTATE COORDINATION OF AMINO-SUBSTITUTED TETRAAZACYCLOALKANES TO COBALT(III) .3. SYNTHESIS OF AN UNSYMMETRIC LIGAND AND CRYSTAL-STRUCTURE OF ITS CIS-CHLOROCOBALT(III) COMPLEX', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1649-1652 (1992)
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1991 |
Lawrance GA, Martinez M, Skelton BW, White AH, 'Quinquedentate coordination of 6-Methyl-1,11-dithia-4,8-diazacyclotetradecan-6-amine to Cobalt(III). X-Ray Crystal Structure of the [Co(N
The pendant arm macrocycle 6-methyl-1,11-dithia-4,8-diazacyclotetradecan-6-amine (7) can coordinate to cobalt(III) as a quinquedentate N3S2 ligand. Spectroscopy indicated a geomet... [more]
The pendant arm macrocycle 6-methyl-1,11-dithia-4,8-diazacyclotetradecan-6-amine (7) can coordinate to cobalt(III) as a quinquedentate N3S2 ligand. Spectroscopy indicated a geometry with the macrocycle folded and the pendant amine and the unidentate donor in cis dispositions for the [Co(7) Cl ]2+ and [Co(7)(OOCCH3)]2+ products isolated. An X-ray crystal structure analysis of [Co(7)(OOCCH3)](ClO4)2.H2O characterized the cis stereochemistry. The complex crystallized in the Pbca space group, a 10.620(9), b 13.926(9), c 32.35(2)¿, and analysis defined a distorted octahedral geometry with the primary and two secondary nitrogen donors occupying an octahedral face with relatively short Co-N bonds [1.937(7)-1.950(7)¿], the acetate ion [Co-O 1.905(6)¿] trans to one of the secondary amine donors and thioether donors [Co-S 2.223(3), 2.227(3)¿] trans to the other nitrogen donors. Significant angle distortions occur around the metal ion. Base hydrolysis of the chloro complex is slow and stereoretentive, with a rate constant of 1.08¿103 dm3 mol-1 s-1 at 25YC, 15-fold faster than for the pentaaza analogue. © 1991 ASEG.
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1991 |
CReaser II, Harrowfield JM, Lawrance GA, 'Rapid reduction of [cu
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1991 |
LAWRANCE GA, MARTINEZ M, SKELTON BW, WHITE AH, 'QUINQUEDENTATE COORDINATION OF 6-METHYL-1,11-DITHIA-4,8-DIAZACYCLOTETRADECAN-6-AMINE TO COBALT(III) - X-RAY CRYSTAL-STRUCTURE OF THE [CO(N3S2)(OOCCH3)] (CLO4)2.H2O COMPLEX', AUSTRALIAN JOURNAL OF CHEMISTRY, 44 113-121 (1991)
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1991 |
LAWRANCE GA, MAEDER M, OLEARY MA, SKELTON BW, WHITE AH, 'MACROCYCLE FORMATION FROM COPPER(II)DIRECTED CONDENSATION OF LINEAR TETRAAMINES WITH FORMALDEHYDE ALONE AND WITH ADDED 2-AMINOETHANOL', AUSTRALIAN JOURNAL OF CHEMISTRY, 44 1227-1236 (1991)
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1991 |
LAWRANCE GA, SKELTON BW, WHITE AH, WILKES EN, 'TETRAAZACYCLOALKANES WITH PENDANT CARBOXYLATES - COPPER(II)-DIRECTED SYNTHESES AND CRYSTAL-STRUCTURE OF (ETHYL 1,5,9,13-TETRAAZABICYCLO[11.2.2]HEPTADECANE-7-CARBOXYLATE)COPPER(II) PERCHLORATE', AUSTRALIAN JOURNAL OF CHEMISTRY, 44 1511-1522 (1991)
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1991 |
BERNHARDT PV, COMBA P, HAMBLEY TW, LAWRANCE GA, 'COORDINATION OF THE SEXIDENTATE MACROCYCLE 6,13-DIMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECANE-6,13-DIAMINE TO IRON(III)', INORGANIC CHEMISTRY, 30 942-946 (1991)
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1991 |
HOLLINGSHED GK, LAWRANCE GA, MAEDER M, ROSSIGNOLI M, 'POLYAMINE COMPLEXATION .1. STABILITY-CONSTANTS FOR METAL-ION COMPLEXATION OF 5-(4'-AMINO-2'-AZABUTANE)-5-METHYL-3,7-DIAZANONANE-1,9-DIAMINE', POLYHEDRON, 10 409-413 (1991)
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1991 |
BERNHARDT PV, LAWRANCE GA, SANGSTER DF, 'PULSE-RADIOLYSIS OF MONONUCLEAR AND BINUCLEAR COPPER(II) MACROCYCLIC COMPLEXES', POLYHEDRON, 10 1373-1377 (1991)
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1991 |
COMBA P, HAMBLEY TW, LAWRANCE GA, MARTIN LL, RENOLD P, VARNAGY K, 'TEMPLATE SYNTHESES OF CHIRAL TETRADENTATE LIGANDS DERIVED FROM L-AMINO-ACIDS - STRUCTURAL AND SPECTROSCOPIC CHARACTERIZATION OF THE FREE LIGANDS AND OF THEIR COPPER(II) COMPLEXES', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 277-283 (1991)
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1991 |
BERNHARDT PV, LAWRANCE GA, MAEDER M, ROSSIGNOLI M, HAMBLEY TW, 'SEXIDENTATE COORDINATION OF THE PENDANT-ARM MACROCYCLE 6,13-DIMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECANE-6,13-DIAMINE (L1) TO ZINC(II) - CRYSTAL-STRUCTURE OF [ZNL1][CLO4]2.H2O', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1167-1182 (1991)
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1990 |
COMBA P, LAWRANCE GA, MANNING TM, MARKIEWICZ A, MURRAY KS, OLEARY MA, et al., 'SYNTHESIS, CRYSTAL-STRUCTURE AND MAGNETISM OF A MACROCYCLIC BINUCLEAR DICOPPER(II) AMINO ALCOHOL COMPLEX FROM A METAL-DIRECTED REACTION INVOLVING FORMALDEHYDE AND NITROETHANE', AUSTRALIAN JOURNAL OF CHEMISTRY, 43 69-78 (1990)
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1990 |
BERNHARDT PV, LAWRANCE GA, SKELTON BW, WHITE AH, 'FACILE METAL-DIRECTED SYNTHESIS AND CRYSTAL-STRUCTURE OF A NEW AMINO-ACID ESTER, METHYL 3-[(2-AMINOETHYL)AMINO]-2-[(2-AMINOETHYL)AMINOMETHYL]PROPIONATE, AS THE COPPER(II) COMPLEX', AUSTRALIAN JOURNAL OF CHEMISTRY, 43 399-404 (1990)
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1990 |
BERNHARDT PV, HAMBLEY TW, LAWRANCE GA, 'CRYSTAL-STRUCTURES OF [H4L] (CLO4)4.6H2O AND [ZN(H2L)(S2O6)2].4H2O (L = 6,13-DIMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECANE-6,13-DIAMINE)', AUSTRALIAN JOURNAL OF CHEMISTRY, 43 699-706 (1990)
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1990 |
BERNHARDT PV, COMBA P, GAHAN LR, LAWRANCE GA, 'DICOPPER(II) COMPLEXES OF SPIRO MACROBICYCLES WITH AZA AND THIA AZA DONOR SETS', AUSTRALIAN JOURNAL OF CHEMISTRY, 43 2035-2044 (1990)
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1990 |
BERNHARDT PV, LAWRANCE GA, 'COMPLEXES OF POLYAZA MACROCYCLES BEARING PENDENT COORDINATING GROUPS', COORDINATION CHEMISTRY REVIEWS, 104 297-343 (1990)
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1990 |
BERNHARDT PV, COMBA P, CURTIS NF, HAMBLEY TW, LAWRANCE GA, MAEDER M, SIRIWARDENA A, 'COORDINATION OF THE PENDANT-ARM MACROCYCLE 6,13-DIAMINO-6,13-DIMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECANE TO CHROMIUM(III) - CRYSTAL-STRUCTURE AND PHYSICAL-PROPERTIES OF THE HEXACOORDINATED COMPLEX ION', INORGANIC CHEMISTRY, 29 3208-3213 (1990)
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1990 |
Guo LH, Hill HAO, Hopper DJ, Lawrance GA, Sangher GS, 'Direct voltammetry of the Chromatium vinosum enzyme, sulfide:Cytochrome c oxidoreductase (flavocytochrome c
The electrochemistry of the enzyme, sulfide:cytochrome c oxidoreductase, also known as flavocytochrome c552 from the purple sulfur bacterium, Chromatium vinosum, has been studied ... [more]
The electrochemistry of the enzyme, sulfide:cytochrome c oxidoreductase, also known as flavocytochrome c552 from the purple sulfur bacterium, Chromatium vinosum, has been studied using several modified electrodes. Direct electron transfer between the heme of the flavocytochrome and an electrode is observed in the presence of a redox-inactive cationic species which promotes the voltammetry of the enzyme. Quasi-reversible electron transfer was achieved using the aminoglycoside, neomycin, as a promoter at either a modified gold or polished edge-plane graphite electrode. Further evidence for direct electron transfer is provided by the catalytic response of the enzyme at the electrode in the presence of substrate. Also reported is the direct spectroelectrochemistry of flavocytochrome c552 at an optically transparent thin layer gold electrode modified with Cys-Glu-Cys in the presence of neomycin.
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1990 |
DIXON NE, LAWRANCE GA, LAY PA, SARGESON AM, TAUBE H, 'TRIFLUOROMETHANESULFONATES AND TRIFLUOROMETHANESULFONATO-0 COMPLEXES', INORGANIC SYNTHESES, 28 70-76 (1990)
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1990 |
LAWRANCE GA, MAEDER M, OLEARY MA, WOON FH, 'MACROMONOCYCLE FORMATION FROM COPPER(II)-DIRECTED OR NICKEL(II)-DIRECTED CONDENSATION OF LINEAR TETRAAMINES AND FORMALDEHYDE WITH VARIOUS NITRO-CARBON ACIDS', POLYHEDRON, 9 2227-2231 (1990)
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1990 |
BERNHARDT PV, LAWRANCE GA, HAMBLEY TW, 'COBALT(III) COMPLEXES OF 1,5,9-TRIAMINO-5-METHYL-3,7-DIAZANONANE,L1, A NEW QUINQUEDENTATE POLYAMINE LIGAND - CRYSTAL-STRUCTURES OF THE CHLOROCOBALT(III) AND MU-SUPEROXO-DICOBALT(III) COMPLEXES OF L1', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 235-241 (1990)
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1990 |
LAWRANCE GA, MAEDER M, MANNING TM, OLEARY MA, SKELTON BW, WHITE AH, 'SYNTHESIS AND CHARACTERIZATION OF DINICKEL(II) AND DIPALLADIUM(II) COMPLEXES OF THE MACROCYCLIC BINUCLEATING LIGAND 3,13-DIMETHYL-3,13-DINITRO-1,5,11,15-TETRA-AZACYCLOEICOSANE-8,18-DITHIOL (L5) - CRYSTAL-STRUCTURE OF THE COMPLEX [NI2(L5-2H)][NO2]2.3.5H2O', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 2491-2495 (1990)
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1990 |
BERNHARDT PV, LAWRANCE GA, PATALINGHUG WC, SKELTON BW, WHITE AH, CURTIS NF, SIRIWARDENA A, 'COORDINATION OF 6,13-DIMETHYL-1,4,8,11-TETRA-AZACYCLOTETRADECANE-6,13-DIAMINE TO PLATINUM(II) AND PALLADIUM(II) - SYNTHESES, CHARACTERIZATION, AND X-RAY CRYSTAL-STRUCTURES OF THE PERCHLORATE SALTS OF BOTH COMPLEXES', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 2853-2858 (1990)
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1990 |
BERNHARDT PV, LAWRANCE GA, COMBA P, MARTIN LL, HAMBLEY TW, 'SYNTHESIS, PHYSICAL-PROPERTIES AND X-RAY CRYSTAL-STRUCTURE OF AN OXOVANADIUM(IV) COMPLEX OF THE PENDANT-ARM MACROCYCLE 6,13-DIMETHYL-1,4,8,11-TETRA-AZACYCLOTETRADECANE-6,13-DIAMINE', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 2859-2862 (1990)
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1990 |
BERNHARDT PV, LAWRANCE GA, HAMBLEY TW, 'RHODIUM(III) COMPLEXES OF THE AMBIDENTATE MACROCYCLE 6,13-DIAMINO-6,13-DIMETHYL-1,4,8,11-TETRA-AZACYCLOTETRADECANE - CRYSTAL-STRUCTURE OF THE SEXIDENTATE COMPLEX', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 983-987 (1990)
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1990 |
Lawrance GA, Sargeson AM, Lay PA, 'Organic substituent effects in macrobicyclic (hexaamine)cobalt(III/II) complexes: A new method of obtaining polar substituent constants', Inorganic Chemistry, 29 4808-4816 (1990)
The redox potentials, E1/2, for the reversible cobalt(III/II) redox couples of complexes of substituted macrobicyclic ligands derived from 3,6,10,13,16,19-hexaazabicyclo[6.6.6]ico... [more]
The redox potentials, E1/2, for the reversible cobalt(III/II) redox couples of complexes of substituted macrobicyclic ligands derived from 3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane show a substantial variation with the type of substituent. The variation was subjected to a Hammett type treatment yielding a series of inductive or polar substituent constants sE that correlate with the organic substituent constants (s1)obtained by a variety of other methods. Changes in E1/2 with substituent are not reflected in changes in the ligand field spectra of either oxidation states. We deduce, therefore, that the effects are not transmitted via through-space overlap of orbitals or through-bond induction. The effects can be attributed to either a through-space Coulombic mechanism or interactions through the s framework. In the case of the NHR2+ and NR3+ substituents, there is a steric substituent effect that forces the Co(III) cage complexes from a lel3 to ob3 conformation and results in quite different spectroscopic and electrochemical properties. The correlations of sE values with the 1H, 13C, and 59Co NMR chemical shifts are also examined. The sE constants are readily obtained, and this may prove to be a more versatile method of obtaining polar substituent constants than those currently used in physical organic chemistry. © 1990, American Chemical Society. All rights reserved.
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1989 |
BERNHARDT PV, CURTIS LS, CURTIS NF, LAWRANCE GA, SKELTON BW, WHITE AH, 'CONDENSATIONS OF ETHANE-1,2-DIAMINE, FORMALDEHYDE AND AMMONIA (OR NITROETHANE) DIRECTED BY NICKEL(II) OR COPPER(II) - CRYSTAL-STRUCTURE OF (8-METHYL-8-NITRO-1,3,6,10,13,15-HEXAAZATRICYCLO[13.1.1.1 13,15]OCTADECANE)NICKEL(II) PERCHLORATE', AUSTRALIAN JOURNAL OF CHEMISTRY, 42 797-811 (1989)
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1989 |
BERNHARDT PV, LAWRANCE GA, SKELTON BW, WHITE AH, 'COORDINATION OF THE HEXACYANOFERRATE(III) ANION TO A POLYAMMONIUM MACROCYCLE - CRYSTAL-STRUCTURE OF [H4L]1.5[FE(CN)6]2 (L=6,13-DIMETHYL-1,4,8,11-TETRAAZA-CYCLOTETRADECANE-6,13-DIAMINE)', AUSTRALIAN JOURNAL OF CHEMISTRY, 42 1035-1043 (1989)
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1989 |
ENGELHARDT LM, KEEGAN EA, LAWRANCE GA, WHITE AH, 'SYNTHESIS, CHARACTERIZATION AND ENHANCED CLEAVAGE OF DIPHOSPHATE AND TRIPHOSPHATE BOUND TO TETRAAMINECOBALT(III) CENTERS - CRYSTAL-STRUCTURE OF [N,N-BIS(2-AMINOETHYL)ETHANE-1,2-DIAMINE](DIPHOSPHATO)COBALT(III) PERCHLORATE MONOHYDRATE', AUSTRALIAN JOURNAL OF CHEMISTRY, 42 1045-1055 (1989)
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1989 |
ENGELHARDT LM, LAWRANCE GA, MANNING TM, WHITE AH, 'COPPER(II) AND COBALT(III) COMPLEXES OF A MIXED SECONDARY AND TERTIARY NITROGEN DONOR TETRAAZA MACROCYCLE - CRYSTAL-STRUCTURE OF AQUA(7-METHYL-7-NITRO-1,5,9,13-TETRAAZA-BICYCLO[11.2.2]HEPTADECANE)COPPER(II) PERCHLORATE HYDRATE', AUSTRALIAN JOURNAL OF CHEMISTRY, 42 1859-1867 (1989)
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1989 |
CURTIS NJ, LAWRANCE GA, VANELDIK R, 'ACTIVATION VOLUMES FOR AQUATION OF CHROMIUM(III) PENTAAMMINE COMPLEXES WITH NEUTRAL LEAVING GROUPS - COMPARISON WITH AND MECHANISTIC DIFFERENTIATION FROM COBALT(III) ANALOGS', INORGANIC CHEMISTRY, 28 329-333 (1989)
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1989 |
Guardado P, Lawrance GA, van Eldik R, 'Mechanistic Information on Base Hydrolysis and Base-Promoted Linkage Isomerization Reactions of Chromium(III) Amine Complexes from Volumes of Activation', Inorganic Chemistry, 28 976-978 (1989)
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1989 |
BERNHARDT PV, HAMBLEY T, LAWRANCE GA, 'COORDINATION OF 6,13-DIAMINO-6,13-DIMETHYL-1,4,8,11-TETRA-AZACYCLOTETRADECANE TO IRON(III) - THE 1ST FULLY CHARACTERIZED HEXA-AMINEIRON(III) COMPLEX', JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, 553-554 (1989)
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1989 |
BERNHARDT PV, LAWRANCE GA, HAMBLEY TW, '6,13-DIAMINO-6,13-DIMETHYL-1,4,8,11-TETRA-AZACYCLOTETRADECANE, L7, A NEW, POTENTIALLY SEXIDENTATE POLYAMINE LIGAND - VARIABLE COORDINATION TO COBALT(III) AND CRYSTAL-STRUCTURE OF THE COMPLEX [CO(L7)]CL2[CLO4]', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1059-1065 (1989)
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1989 |
LAWRANCE GA, 'LEAVING GROUPS ON INERT METAL-COMPLEXES WITH INHERENT OR INDUCED LABILITY', ADVANCES IN INORGANIC CHEMISTRY, 34 145-194 (1989)
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1989 |
Kitamura Y, Lawrance GA, van Eldik R, 'Volumes of Activation and volume Profiles as Mechanistic Criteria for Base Hydrolysis Reactions of Cobalt(III) Amine Complexes', Inorganic Chemistry, 28 333-338 (1989)
Volumes of activation (¿V*exptl) and reaction volumes (¿VBH) for the base hydrolysis of 16 different cobalt(III) amine complexes of the type CoL5X3+, CoL5X2+, CoL4X2+, and CoL4XY+... [more]
Volumes of activation (¿V*exptl) and reaction volumes (¿VBH) for the base hydrolysis of 16 different cobalt(III) amine complexes of the type CoL5X3+, CoL5X2+, CoL4X2+, and CoL4XY+were determined from high-pressure kinetic and dilatometric measurements, respectively. The values of ¿V*Mptlrange from 43 to 19 cm3mol-1, and those for ¿VBHrange from 24 to 9 cm3mol-1, depending on the charge on the complex as determined by that on the leaving group X. The data are very consistent with earlier reported data for closely related systems and demonstrate clearly both the minor role played by the nonparticipating ligands L, and the influence of complex charge. The reported results are all in line with a SN1CB mechanism. However, evidence for apparent cases involving rate-limiting deprotonation rather than the usual rate-determining ligand dissociation process was not forthcoming, since no differentiation on the basis of ¿V#exptwas observed. © 1989, American Chemical Society. All rights reserved.
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1989 |
Guo LH, Hill HAO, Lawrance GA, Sanghera GS, Hopper DJ, 'Direct un-mediated electrochemistry of the enzyme P-cresolmethylhydroxylase', Journal of Electroanalytical Chemistry, 266 379-396 (1989)
The enzyme p-cresolmethylhydroxylase, from Pseudomonas putida, is involved in the degradative pathway of p-cresol. The direct, un-mediated reversible electron transfer between the... [more]
The enzyme p-cresolmethylhydroxylase, from Pseudomonas putida, is involved in the degradative pathway of p-cresol. The direct, un-mediated reversible electron transfer between the heme of the flavocytochrome enzyme and an edge-plane graphite electrode in the presence of redox-inactive cationic species as promoters of the enzyme electrochemistry is reported. Diffusion controlled heterogeneous electron transfer is modulated by the levels and type of promoter used, which range from simple and complex cations to polyamines and aminoglycosides. The promoter-enzyme assembly affords a degree of macromolecular recognition at the electrode as both the cationic charge and the flexible nature of the promoter are important to achieve direct electron transfer. A quasi-reversible cyclic voltammetric response was observed in the absence of substrate from which the heterogeneous rate of electron transfer between the enzyme and the electrode was determined as ks ~ ~ 1.8 × 10-4 cm2 s-1. An enzyme titration with optimal concentrations of promoter and substrate p-cresol yielded a linear relationship between catalytic current and enzyme concentration up to 1.2 µM. Similarly, relationships were obtained to p-cresol and p-hydroxybenzylalcohol concentrations with fixed amounts of enzyme and promoter, both yielding a linear current vs. substrate response up to 0.5 m M. Furthermore, the magnitude of the catalytic current of p-cresol is greater than that obtained for mediation with the enzyme's natural redox partner, azurin, but comparable to those obtained with a ferrocene mediator. Catalytic response was also obtained at a peptide-modified gold electrode in the presence of a promoter, spermine. © 1989.
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1989 |
Hill HAO, Lawrance GA, 'Some consequences of mixed and dilute surface modification of gold electrodes for protein electrochemistry', Journal of Electroanalytical Chemistry, 270 309-318 (1989)
Modification of a gold working electrode with apparently equivalent amounts of -S-(CH2)2-COO- and -S-(CH2)-NH+3 produces an electrode which permits direct unmediated electrochemis... [more]
Modification of a gold working electrode with apparently equivalent amounts of -S-(CH2)2-COO- and -S-(CH2)-NH+3 produces an electrode which permits direct unmediated electrochemistry of both positively-charged horse heart cytochrome c and negatively-charged (at pH 7) membrane-cleaved cytochrome b5, proteins. By varying the ratio of carboxylate : amine modifiers, the relationship between " active " groups on the surface and current could be probed: for cytochrome c, 1 : 9 carboxylate: amine is sufficient to obtain a maximum current; for cytochrome b5, approximately 3:1 carboxylate : amine is necessary for a maximum current, after which the current is unaffected by the ratio of carboxylate : amine. The overall behaviour is consistent with the demand by the particular protein for a certain density of appropriate groups on the surface to accommodate hydrogen-bonding interactions which facilitate the formation of an electrode/protein complex prior to electron transfer. With surfaces modified with a very dilute amount of the required group, initially sigmoidal voltammograms are observed, most consistent with a radial diffusion model based on an array of isolated sites on the surface. However, this changes slowly with time to display " normal " cyclic voltammetry, consistent with rearrangement of modifier groups on the surface to configurations more appropriate for regular electron transfer. This protein-directed surface rearrangement is also observed using cytochrome c and a dilute coverage of the modifier 1-thio-ß-D-glucose tetraacetate. Normally, modification with this molecule produces an efficient and, presumably, dense monolayer coverage of the surface which shows stable voltammetry with cytochrome c, but no response with cytochrome b5. Hydrogen bonding between acetate groups on the modifier and lysine residues on the protein are considered important, since hydrolysis of the acetates removes electrochemical response. © 1989.
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1988 |
COMBA P, LAWRANCE GA, ROSSIGNOLI M, SKELTON BW, WHITE AH, 'SYNTHESIS OF A CIS-N2S2 DONOR MACROCYCLE BY METAL-DIRECTED CONDENSATION OF FORMALDEHYDE, NITROETHANE AND A DIAMINODITHIAALKANE - CRYSTAL-STRUCTURE OF THE (6-METHYL-6-NITRO-1,11-DITHIA-4,8-DIAZACYCLOTETRADECANE)-COPPER(II) PERCHLORATE PRODUCT', AUSTRALIAN JOURNAL OF CHEMISTRY, 41 773-781 (1988)
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1988 |
FOWLESS AD, LAWRANCE GA, STRANKS DR, SULLIVAN TR, VANDERHOEK N, 'THE EFFECT OF PRESSURE ON THE ANATION OF DIAQUABIS(ETHANE-1,2-DIAMINE)COBALT(III) BY SELENATE AND SULFATE, AND ON THE ISOMERIZATION OF THE TRANS-AQUABIS(ETHANE-1,2-DIAMINE)(HYDROGENSELENITO)COBALT(III) ION', AUSTRALIAN JOURNAL OF CHEMISTRY, 41 1263-1273 (1988)
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1988 |
LAWRANCE GA, OLEARY MA, SKELTON BW, WOON FH, WHITE AH, 'REACTIONS OF (10-METHYL-10-NITRO-1,4,8,12-TETRAAZA-CYCLOPENTADECANE)COPPER(II) ION IN AQUEOUS HYDROCHLORIC-ACID, INCLUDING ZINC REDUCTION - CRYSTAL-STRUCTURE OF (2-METHYL-1,4,8,11-TETRAAZA-CYCLOTETRADEC-1-ENE)COPPER(II) PERCHLORATE', AUSTRALIAN JOURNAL OF CHEMISTRY, 41 1533-1544 (1988)
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1988 |
BERNHARDT PV, LAWRANCE GA, SANGSTER DF, 'NICKEL(I) AND NICKEL(III) COMPLEXES OF SUBSTITUTED TETRAAZA MACROCYCLES FORMED BY PULSE-RADIOLYSIS AND ELECTROCHEMISTRY OF NICKEL(II) PRECURSORS', INORGANIC CHEMISTRY, 27 4055-4059 (1988)
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1988 |
LAWRANCE GA, MANNING TM, SKELTON BW, WHITE AH, 'COORDINATED ETHER FORMATION IN THE METAL-DIRECTED CONDENSATION AND MACROCYCLIZATION OF FORMALDEHYDE, ETHANOLAMINE, AND A POLYAMINE', JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, 1344-1345 (1988)
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1988 |
LAWRANCE GA, MANNING TM, OLEARY MA, 'METAL-DIRECTED SYNTHESIS OF THE NEW POTENTIALLY PENTADENTATE AMINOALCOHOL LIGAND 5-AMINO-5-METHYL-3,7-DIAZANONAN-1,9-DIOL BASED ON ETHANOLAMINE', POLYHEDRON, 7 1263-1266 (1988)
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1988 |
CURTIS NJ, HENDRY P, LAWRANCE GA, 'THE PH AND TEMPERATURE-DEPENDENT HYDROLYSES OF [N,N-BIS(2-AMINOETHYL)-1,2-ETHANEDIAMINE]BIS(SOLVENT)COBALT(III) AND BIS(DIMETHYLFORMAMIDE) (1,4,7,10-TETRA-AZACYCLODODECANE)COBALT(III) COMPLEXES', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 47-51 (1988)
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1988 |
COMBA P, CURTIS NF, LAWRANCE GA, OLEARY MA, SKELTON BW, WHITE AH, 'SYNTHESIS OF A 13-MEMBERED TETRA-AZAMACROCYCLE EMPLOYING FORMALDEHYDE AND NITROALKANES DIRECTED BY METAL-IONS - CRYSTAL-STRUCTURES OF (12-METHYL-12-NITRO-1,4,7,10-TETRA-AZACYCLOTRIDECANE)COPPER(II) PERCHLORATE AND MU-CHLORO-1,1,1-TRICHLORO-2-(12-METHYL-12-NITRO-1,4,7,10-TETRA-AZACYCLOTRIDECANE)DICOPPER(II)2', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 497-502 (1988)
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1988 |
DIVER C, LAWRANCE GA, 'TRIFLUOROMETHANESULPHONATO-O COMPLEXES OF PLATINUM(II) AND PALLADIUM(II)', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 931-934 (1988)
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1988 |
COMBA P, CURTIS NF, LAWRANCE GA, OLEARY MA, SKELTON BW, WHITE AH, 'COMPARISONS OF 13-MEMBERED TO 16-MEMBERED TETRA-AZACYCLOALKANE COPPER(II) COMPLEXES DERIVED FROM TEMPLATE SYNTHESES INVOLVING NITROETHANE AND FORMALDEHYDE - CRYSTAL-STRUCTURES OF (10-METHYL-10-NITRO-1,4,8,12-TETRA-AZACYCLOPENTADECANE)COPPER(II) AND (3-METHYL-3-NITRO-1,5,9,13-TETRA-AZACYCLOHEXADECANE)COPPER(II) PERCHLORATESE', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 2145-2152 (1988)
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1988 |
Creaser II, Lancaster MJ, Lawrance GA, Sargeson AM, Sullivan JC, 'Oxidation of formatopentaamminecobalt(iii) perchlorate by silver(II)', Australian Journal of Chemistry, 41 1275-1287 (1988)
Formatopentaamminecobalt(III) perchlorate is oxidized relatively rapidly by AgO in acid conditions (1 m H2SO4, HNO3 or HO3SCF3), with approximately 97% of the total cobalt retaine... [more]
Formatopentaamminecobalt(III) perchlorate is oxidized relatively rapidly by AgO in acid conditions (1 m H2SO4, HNO3 or HO3SCF3), with approximately 97% of the total cobalt retained in the cobalt(III) state as [Co(NH3)5(OH2)]3+ and [Co(NH3)5X]n+ (X = S042- or NO3-). A combination of product distribution, silver(I) and silver(II) concentration dependence and 18O-labelling experiments indicate that the major pathway (97%) is oxidation of [Co(NH3)5(OCHO)]2+ directly to [(NH3)5Co(OCO)]3+ and [(NH3)5Co(O2COH)]2+ by AgIII (through the disproportionation 2AgII ¿AgIII + AgI) in a relatively rapid hydride extraction. A minor path (3%) appears to involve a one-electron oxidation by AgII to the complexed radical anion [(NH3)5Co(OC¿O)]2+ which then decays intramolecularly to yield CoII and CO2. In 1 M H2SO4 the cobalt(III) intermediate, [(NH3)5Co(OCO)]3+, has been shown by 18O-labelling and competition experiments to decay by dissociation into [Co(NH3)5]3+ and CO2. The pentacoordinate intermediate [Co(NH3)5]3+ immediately captures OH2 and HSO4-. © 1988 ASEG.
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1987 |
HAMBLEY TW, LAWRANCE GA, SANGSTER DF, WARD CB, 'CHARACTERIZATION, REDOX PROPERTIES AND PULSE-RADIOLYSIS STUDY OF DICHLORO-(TETRAAZACYCLOTETRADECANE)MANGANESE(III) COMPLEXES, AND X-RAY CRYSTAL-STRUCTURE OF THE MESO-5,7,7,12,14,14-HEXAMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECANE COMPLEX', AUSTRALIAN JOURNAL OF CHEMISTRY, 40 883-893 (1987)
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1987 |
LAWRANCE GA, ROSSIGNOLI M, SKELTON BW, WHITE AH, 'METAL-DIRECTED SYNTHESIS INVOLVING FORMALDEHYDE AND NITROETHANE, AND CRYSTAL-STRUCTURE OF THE COPPER(II) COMPLEX OF THE 14-MEMBERED MACROCYCLE 6-METHYL-6-NITRO-1,4,8,11-TETRAAZACYCLOTETRADECANE', AUSTRALIAN JOURNAL OF CHEMISTRY, 40 1441-1449 (1987)
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1987 |
CURTIS NF, GAINSFORD GJ, HAMBLEY TW, LAWRANCE GA, MORGAN KR, SIRIWARDENA A, 'HEXACO-ORDINATION OF A DIAMINO-SUBSTITUTED TETRA-AZAMACROCYCLE TO COBALT(III) AND NICKEL(II) - COMPRESSED CO-N BONDS', JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, 295-297 (1987)
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1987 |
LAWRANCE GA, VANELDIK R, 'AQUATION OF NEUTRAL LIGANDS FROM PENTA-AMMINE-COBALT(III) AND PENTA-AMMINE-CHROMIUM(III) IONS - MECHANISTIC DIFFERENTIATION', JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, 1105-1106 (1987)
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1987 |
LAWRANCE GA, OLEARY MA, 'MACROCYCLIC TETRAAMINES FROM REACTION OF THE (1,10-DIAMINO-4,7-DIAZADECANE)COPPER(II) CATION WITH FORMALDEHYDE AND THE CARBON ACIDS NITROETHANE AND DIETHYLMALONATE - VARIABILITY IN REACTIVITY', POLYHEDRON, 6 1291-1294 (1987)
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1987 |
BERNHARDT PV, LAWRANCE GA, 'SYNTHESES OF (IMIDAZOLE)PENTAAMMINEMETAL(III) AND MU-IMIDAZOLATODECAAMMINEDIMETAL(III) COMPLEXES FROM TRIFLUOROMETHANESULFONATO PRECURSORS', POLYHEDRON, 6 1347-1350 (1987)
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1987 |
BERNHARDT PV, LAWRANCE GA, 'TRIFLUOROMETHANESULFONATO COMPLEXES OF (1,4,8,11-TETRAAZACYCLOTETRADECANE)COBALT(III) AND RUTHENIUM(III) WITH TRANS GEOMETRY', POLYHEDRON, 6 1875-1878 (1987)
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1987 |
LAWRANCE GA, SANGSTER DF, 'REACTIONS OF CHROMIUM(III) COMPLEXES OF 1,10-PHENANTHROLINE,2,2'-BIPYRIDYL, AND OXALATE WITH THE PULSE RADIOLYTICALLY GENERATED AQUATED ELECTRON, ZINC(I), AND CADMIUM(I)', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1425-1429 (1987)
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1986 |
LAWRANCE GA, SKELTON BW, WHITE AH, COMBA P, 'AN UNUSUAL CLEAVAGE AND MACROCYCLIZATION IN THE ZINC-AQUEOUS ACID REDUCTION OF [2-METHYL-2-NITRO-N,N'-BIS(PYRIDIN-2-YLMETHYL)-PROPANE-1,3-DIAMINE]COPPER(II) CATION - CRYSTAL-STRUCTURE OF THE (6,13-DIMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECANE-6,13-DIAMINE)COPPER(II) PERCHLORATE PRODUCT', AUSTRALIAN JOURNAL OF CHEMISTRY, 39 1101-1108 (1986)
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1986 |
HAMMERSHOI A, LAWRANCE GA, SARGESON AM, 'REDOX PROPERTIES OF MACROTRICYCLIC HEXAAMINE COBALT(III) COMPLEXES', AUSTRALIAN JOURNAL OF CHEMISTRY, 39 2183-2186 (1986)
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1986 |
LAWRANCE GA, 'COORDINATED TRIFLUOROMETHANESULFONATE AND FLUOROSULFATE', CHEMICAL REVIEWS, 86 17-33 (1986)
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1986 |
CURTIS NJ, LAWRANCE GA, LAY PA, SARGESON AM, 'HYDROLYSIS OF COORDINATED TRIFLUOROMETHANESULFONATE FROM COBALT(III), RHODIUM(III), IRIDIUM(III), AND CHROMIUM(III) PENTAAMINES', INORGANIC CHEMISTRY, 25 484-488 (1986)
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1986 |
COMBA P, CURTIS NF, LAWRANCE GA, SARGESON AM, SKELTON BW, WHITE AH, 'TEMPLATE SYNTHESES INVOLVING CARBON ACIDS - SYNTHESIS AND CHARACTERIZATION OF (3,10-DIMETHYL-3,10-DINITRO-1,4,8,11-TETRAAZACYCLOTETRADECANE)COPPER(II) AND (1,9-DIAMINO-5-METHYL-5-NITRO-3,7-DIAZANONANE)COPPER(II) CATIONS AND NITRO-GROUP REDUCTION PRODUCTS', INORGANIC CHEMISTRY, 25 4260-4267 (1986)
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1986 |
Comba P, Creaser II, Martin LL, Sargeson AM, Gahan LR, Lawrance GA, et al., 'Macrobicyclic Chromium(III) Hexaamine Complexes', Inorganic Chemistry, 25 384-389 (1986)
The syntheses and characterization of the macrobicyclic hexaamine chromium(III) complexes of diamsar (1,8-diamino-3,6,10,13,16,19-hexaazabicyclo[6.6.6]eicosane) and sar (3,6,10,13... [more]
The syntheses and characterization of the macrobicyclic hexaamine chromium(III) complexes of diamsar (1,8-diamino-3,6,10,13,16,19-hexaazabicyclo[6.6.6]eicosane) and sar (3,6,10,13,16,19-hexaazabicyclo[6.6.6]eicosane) ligands (1¿3) are reported. The complexes were isolated as stable, paramagnetic, and monomeric salts. crystallized in the space group P21/c, (Z = 4, a = 9.474 (2) A, b = 13.331 (3) A, c = 18.221 (5) A, ß = 92.756 (0)°) with the octahedral cation in the C3-lel conformation and an average Cr-N distance of 2.070 (3) A. The complexes are high-spin d3 with room-temperature magnetic moments near the spin-only value of 3.87 µB¿ The aqueous electrochemistry exhibits a quasi-reversible Cr(III/II) couple below -1 V for each complex and a further irreversible Cr(II/0) reduction near -1.6 V; the chromium(II) complexes are not stable in the coulometric time scales (minutes). The Cr(III) electronic spectra show the expected spin-allowed absorption bands of 4T2g4A2gand 4T1g4A2g origin as well as weak spin-forbidden bands of 2Eg, 2Tlg4Agorigin in the visible region. The first of these (4T2gtransition) is split by -400 cm-1and is relatively high in intensity, and the splitting is probably due to the lowered symmetry (D3). Cr(sar)3+ and Cr(diamsar)3+ emit rather strongly at 77 K 0.02), but give no detectable emission above 273 K. Photodecomposition of Cr(diamsar)3+ is ~ 104-fold smaller than that of the Cr(en)33+ ion, and possible reasons for this are discussed. © 1986, American Chemical Society. All rights reserved.
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1986 |
LAWRANCE GA, SANGSTER DF, 'PULSE-RADIOLYSIS AND VOLTAMMETRY OF BIS(DIAMINE)DIOXORHENIUM(V) COMPLEXES', POLYHEDRON, 5 1553-1558 (1986)
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1986 |
LAWRANCE GA, 'VARIATION OF ACTIVATION VOLUMES FOR AQUATION OF CHLOROAMINECOBALT(III) COMPLEXES', POLYHEDRON, 5 2113-2115 (1986)
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1986 |
LAWRANCE GA, 'REACTION OF PENTAAMMINE(UREA-O)COBALT(III) CATION WITH CHLORINE AND HYPOCHLOROUS ACID IN AQUEOUS-SOLUTION', TRANSITION METAL CHEMISTRY, 11 396-399 (1986)
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1986 |
CURTIS NJ, LAWRANCE GA, 'SYNTHESES AND ACID AQUATION REACTIONS OF PENTAKIS(METHYLAMINE)COBALT(III) COMPLEXES OF THE NEUTRAL LIGANDS UREA, DIMETHYLSULFOXIDE, DIMETHYLFORMAMIDE, TRIMETHYL PHOSPHATE, AND ACETONITRILE', INORGANIC CHEMISTRY, 25 1033-1037 (1986)
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1985 |
LAWRANCE GA, 'ACTIVATION VOLUMES FOR ACID AQUATION OF IRON(II) COMPLEXES OF ALKYL-SUBSTITUTED BIPYRIDINE AND METHANOL SOLVOLYSIS OF TRIS(PHENANTHROLINE)IRON(II)', AUSTRALIAN JOURNAL OF CHEMISTRY, 38 1117-1122 (1985)
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1985 |
COMBA P, HAMBLEY TW, LAWRANCE GA, 'TEMPLATE SYNTHESIS, CRYSTAL-STRUCTURE, AND SPECTROSCOPIC CHARACTERIZATION OF [N,N'-BIS(2-PYRIDYLMETHYLENE)-1,3-DIAMINO-2-METHYL-2-NITROPROPANE]COPPER(II) PERCHLORATE', HELVETICA CHIMICA ACTA, 68 2332-2341 (1985)
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1985 |
LAWRANCE GA, 'SOLVOLYSIS KINETICS OF PENTAAMMINE(TRIFLUOROMETHANESULFONATO-O) COMPLEXES OF COBALT(III), RHODIUM(III), AND IRIDIUM(III)', INORGANIC CHEMISTRY, 24 323-326 (1985)
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1985 |
CURTIS NJ, LAWRANCE GA, 'FACILE SYNTHESES AND CHARACTERIZATION OF PENTAAMMINECHROMIUM(III) COMPLEXES WITH NEUTRAL O-BOUND AND N-BOUND LIGANDS', INORGANICA CHIMICA ACTA-ARTICLES AND LETTERS, 100 275-279 (1985)
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1985 |
HAMBLEY TW, LAWRANCE GA, WARD CB, SANGSTER DF, 'OBSERVATION OF A MANGANESE(IV) TRANSIENT FOLLOWING OXIDATION OF THE TRANS-DICHLORO(MESO-5,7,7,12,14,14-HEXAMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECANE) MANGANESE(III) ION WITH HYDROXYL RADICAL', INORGANICA CHIMICA ACTA-ARTICLES AND LETTERS, 105 L1-L2 (1985)
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1985 |
HARROWFIELD JM, LAWRANCE GA, SARGESON AM, 'FACILE SYNTHESIS OF A MACROBICYCLIC HEXAAMINE COBALT(III) COMPLEX BASED ON TRIS(ETHYLENEDIAMINE)COBALT(III) - AN ADVANCED UNDERGRADUATE INORGANIC LABORATORY EXPERIMENT', JOURNAL OF CHEMICAL EDUCATION, 62 804-806 (1985)
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1985 |
HAIGHT GP, HAMBLEY TW, HENDRY P, LAWRANCE GA, SARGESON AM, 'RAPID CLEAVAGE OF TRIDENTATE COBALT(III)-CO-ORDINATED TRIPHOSPHATE', JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, 488-491 (1985)
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1985 |
LAWRANCE GA, 'SYNTHESIS AND BASE HYDROLYSIS OF CHLORO(N-(2-PYRIDINYLMETHYLENE)-N'-[3-[(2-PYRIDINYLMETHYLENE)AMINO]-PROPYL]-1,3-PROPANEDIAMINE)COBALT(III) PERCHLORATE', POLYHEDRON, 4 599-601 (1985)
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1985 |
LAWRANCE GA, 'REDOX PROPERTIES OF BIS(1,10-PHENANTHROLINE)-(PYRIDINE)RUTHENIUM(II) COMPLEXES', POLYHEDRON, 4 817-820 (1985)
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1985 |
LAWRANCE GA, SANGSTER DF, 'PULSED RADIOLYSIS OF PERRHENATE IN NEUTRAL AQUEOUS-SOLUTION - COMPARISON WITH PERTECHNETATE', POLYHEDRON, 4 1095-1096 (1985)
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1985 |
CURTIS NJ, LAWRANCE GA, 'SYNTHESIS, CHARACTERIZATION AND ACID-HYDROLYSIS OF [N,N-BIS(2-AMINOETHYL)-1,2-ETHANEDIAMINE]BIS(SOLVENT)COBALT(III) COMPLEXES', JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1923-1927 (1985)
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1985 |
LAWRANCE GA, WARD CB, 'KINETICS OF OXIDATION OF MANGANESE(II) BY PEROXOMONOSULFURIC ACID IN AQUEOUS ACIDIC SOLUTION', TRANSITION METAL CHEMISTRY, 10 258-261 (1985)
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1985 |
ATTALLA MI, LAWRANCE GA, SUMMERS LA, 'A RUTHENIUM-BOUND DIQUATERNARY VIOLOGEN ANALOG - THE [1,1'-(1,3-PROPANEDIYL)-BIS(4,4'-BIPYRIDINIUM]-PENTAAMMINERUTHENIUM(II) CATION', TRANSITION METAL CHEMISTRY, 10 354-356 (1985)
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1985 |
Comba P, Engelhardt LM, Harrowfield JMB, Lawrance GA, Martin LL, Sargeson AM, White AH, 'Synthesis and characterization of a stable hexa-amine vanadium(IV) cage complex', Journal of the Chemical Society, Chemical Communications, 174-176 (1985)
The synthesis, structure, and preliminary aspects of electrochemical, magnetic, e.s.r., and electronic spectroscopic properties of a stable, near-trigonal-prismatic hexa-aminevana... [more]
The synthesis, structure, and preliminary aspects of electrochemical, magnetic, e.s.r., and electronic spectroscopic properties of a stable, near-trigonal-prismatic hexa-aminevanadium(IV) complex are reported.
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1984 |
Hambley TW, Lawrance GA, 'Cis-Aquachlorobis(ethane-1, 2-diamime)ruthenium(III) Trifluoromethanesulfonate: Crystal structure and hydrolysis kinetics', Australian Journal of Chemistry, 37 435-441 (1984)
The pale yellow ruthenium(iii) complex cis-[Ru(H2NCH2CH2NH2)2(OH2)Cl] (CF3SO3)2.H2O crystallized in the space group P1, a 11·661(2), b 9·961(2), c 9·130(2) Å, a 78·83(3), ß 70·42(... [more]
The pale yellow ruthenium(iii) complex cis-[Ru(H2NCH2CH2NH2)2(OH2)Cl] (CF3SO3)2.H2O crystallized in the space group P1, a 11·661(2), b 9·961(2), c 9·130(2) Å, a 78·83(3), ß 70·42(2), ¿ 85·29(2)°, Z 2. The Ru-N, Ru-Cl and Ru-O bond distances in the essentially octahedral ion are 2·10 (average), 2·323(1) and 2·093(2) Å respectively. The complex hydrolyses with retention of configuration in aqueous acid (0·01 m HOSO2CF3, kaq 2·70 × s-1 at 25°C, ¿H¿ 90·6(±1·5) kJ mol-1, ¿S ¿ -28 (± 5) 5K-1 mol-1) and base (0·01 m NaOH, kOH 0·44 mol-1 1. s-1 at 25°C, ¿H ¿ 73·5(± 2·0) kJ mol-1, ¿S ¿ -43(± 7) J K-1 mol-1). © 1987, CSIRO. All rights reserved.
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1984 |
Howlader NC, Haight GP, Hambley TW, Snow MR, Lawrance GA, 'Synthesis, Structure, Electrochemistry, and Ligand Activity of the Dioxobis(µ-sulfido)Bis(Dithiocarbamato)Dimolybdenum(V) Complex', Inorganic Chemistry, 23 1811-1815 (1984)
The synthesis and characterization of the sulfido-bridged oxomolybdenum(V) dimer of dithiocarbamate (NH2CS2-), [Mo2O2S2(dtc)2].2CH3CN, is reported. The complex crystallized in the... [more]
The synthesis and characterization of the sulfido-bridged oxomolybdenum(V) dimer of dithiocarbamate (NH2CS2-), [Mo2O2S2(dtc)2].2CH3CN, is reported. The complex crystallized in the orthorhombic space group Pnma, a = 9.407 (2) Å,b = 20.877 (4) Å, c = 9.010 (2) Å, Z = 4, with the neutral complex molecules hydrogen bonded to the nitrogen of the acetonitrile via the amine group of the dithiocarbamate ligand. Each molybdenum atom is centered above the base of a square-based pyramid, with the oxygen atoms coordinated on the same side of the bent MoS2Mo bridge and a Mo-Mo distance of 2.820 (1) Å. Electrochemistry of the compound in dimethyl sulfoxide and acetonitrile was investigated by dc and ac polarography, cyclic voltammetry at Hg, Pt, and Au working electrodes, and controlled-potential electrolysis. The complex is reduced irreversibly in a two-electron process on both voltammetric and coulometric time scales, apparently with dissociation of the dithiocarbamate ligands occurring. The complex dissolves in aqueous base to produce an ESR-inactive solution that is stable at pH 12 in the absence of oxygen and whose absorption spectrum is consistent with retention of the Mo2O2S22+ core; in air, this solution bleaches by a base-catalyzed path to a colorless solution in which the molybdenum is predominantly present as MoO42-. © 1984, American Chemical Society. All rights reserved.
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1984 |
Dixon NE, Lawrance GA, Lay PA, Sargeson AM, 'Synthetically Versatile (Trifluoromethanesulfonato) metal Amine Complexes', Inorganic Chemistry, 23 2940-2947 (1984)
Facile synthetic routes to complexes of the labile unidentate coordinated trifluoromethanesulfonate (-OSO2CF3) ion are reported for M(NH3)5(OSO2CF3)n+(M = Rh(III), Ir(III), Cr(III... [more]
Facile synthetic routes to complexes of the labile unidentate coordinated trifluoromethanesulfonate (-OSO2CF3) ion are reported for M(NH3)5(OSO2CF3)n+(M = Rh(III), Ir(III), Cr(III), Ru(III) where n = 2; M = Pt(IV) where n = 3), M(NH2CH3)5(OSO2CF3)2+(M = Co(III), Rh(III), Cr(III)), cis-M(en)2(OSO2CF3)2+(M = Rh(III), Ir(III), Cr(III)), and trans-M(en)2Cl(OSO2CF3)+ (M = Rh(III), Ir(III)). The utility of these synthetically versatile intermediates in the preparation of a variety of complexes containing neutral ligands is illustrated. Rate constants for the aquation of the triflato complexes in 0.1 M CF3SO3H at 25 °C span 3 orders of magnitude and for the pentaammine complexes show a reactivity order of Ru(III) > Co(III) ~ Cr(III) ~ Rh(III) » Ir(III) » Pt(IV). For the pentakis(methylamine) complexes, the aquation rate is greater for Co(III), slightly greater for Rh(III), and smaller for Cr(III) in comparison to the corresponding pentaammine complexes. The aquations of M(en)2X(OSO2CF3)+proceed largely without isomerization (<5%), and the triflato complexes are prepared stereospecifically by this route. For the m-M(en)2(0S02CF3)2+ ions, consecutive first-order aquation processes are observed with rate constants k1~ 2k2. © 1984, American Chemical Society. All rights reserved.
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1984 |
Gahan LR, Lawrance GA, Sargeson AM, 'Electrochemistry of macrobicyclic mixed nitrogen-sulfur donor complexes of cobalt(III)', Inorganic Chemistry, 23 4369-4376 (1984)
The redox chemistry of the mixed nitrogen-sulfur donor cobalt(III) complexes with the macrobicyclic ligands 8-methyl-6, 10, 19-trithia-l, 3, 14, 16-tetraazabicyclo[6.6.6]icosane (... [more]
The redox chemistry of the mixed nitrogen-sulfur donor cobalt(III) complexes with the macrobicyclic ligands 8-methyl-6, 10, 19-trithia-l, 3, 14, 16-tetraazabicyclo[6.6.6]icosane (azacapten), l-methyl-8-nitro-3, 13, 16-trithia-6, 10, 19-triazabicyclo[6.6.6]icosane ((NO2)capten), and 8-ammonio-1-methyl-3, 13, 16-trithia-6, 10, 19-triazabicyclo[6.6.6]icosane ((NH3+)capten) qnd of the hexadentate precursor ligand 5-(4-amino-2-thiabutyl)-5-methyl-3,7-dithia-l,9-nonanediamine (ten) has been investigated in aqueous and aprotic solutions. The macrobicyclic complexes exhibit a chemically and electrochemically reversible Co(III)/Co(II) couple near 0 V in aqueous (NHE) and aprotic solutions (Ag/AgCl) and a chemically irreversible but elctrochemically reversible 1-e couple near-1 V, nominally Co(II)/Co(I). In addition, a further multielectron couple is observed for the azacapten complex at more negative potentials. No evidence for oxidation processes was forthcoming. The low-spin d7 cobalt(II) complex of (NH3+)capten has been characterized by ESR spectroscopy at 4.2 K, and the nominally d8 cobalt(I) complex, at 100 K. The former compound exhibits g values at 1.94, 2.21, and 4.22, while the latter compound shows an eight-line pattern at g = 2.17 (A = 67 G) consistent with its formulation as d8 Co(I) and not as a d7 Co(II)-S radical state. © 1984, American Chemical Society. All rights reserved.
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1984 |
LAWRANCE GA, SANGSTER DF, 'DETECTION OF A TRANSIENT RHENIUM(IV)-AMINE COMPLEX FROM PULSE-RADIOLYSIS STUDIES', JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, 1706-1707 (1984)
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1984 |
LAWRANCE GA, SCHNEIDER K, VANELDIK R, 'AQUATION OF CHLOROPENTAAMMINE AND CHLOROPENTAKIS(METHYLAMINE) COMPLEXES OF COBALT(III) AND CHROMIUM(III) - COMPARATIVE ACTIVATION VOLUMES AND MECHANISTIC IMPLICATIONS', INORGANIC CHEMISTRY, 23 3922-3925 (1984)
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1983 |
Curtis NJ, Lawrance GA, Sargeson AM, 'Reduction potentials of pentaammine complexes of cobalt(III), rhodium(III) and iridium(III): Physical correlations', Australian Journal of Chemistry, 36 1327-1339 (1983)
The reduction potentials of a large range of [M(NH3)5L]n+ complexes (M = CoIII, RhIII, IrIII) have been determined in aqueous solution (µ 0.1 m, NaClO4). Irreversible reductions s... [more]
The reduction potentials of a large range of [M(NH3)5L]n+ complexes (M = CoIII, RhIII, IrIII) have been determined in aqueous solution (µ 0.1 m, NaClO4). Irreversible reductions span the range from +0.22 to -0.47 V for cobalt(iii) complexes and from -0.86 to -1.45 V for rhodium(iii), and occur near -1.7 V for iridium(iii), determined against the standard (KCl) calomel electrode. Despite several reports to the contrary in the literature, no correlations exist of E1/2 with absorption spectra (Co and Rh), nuclear magnetic resonance spectra [d(1HN), Co, Rh, Ir, and d(59Co)], vibrational spectra [v(Co-N)], or rates of aquation and base hydrolysis (Co, Rh, Ir). Complexes which undergo outer-sphere [e.g., with Ru(NH3)62+] and predominantly inner-sphere (e.g., with V2+aq) homogeneous electron transfer can be distinguished by the presence or absence of a correlation of ln kex with E1/2 respectively, consistent with the expectations of the Marcus-Hush theory of outersphere electron transfer. © 1983 ASEG.
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1983 |
Boucher HA, Lawrance1a GA, Lay PA, Sargeson AM, Bond AM, Sangster DF, Sullivan JC, 'Macrobicyclic (Hexaamine)platinum(IV) Complexes: Synthesis, Characterization, and Electrochemistry', Journal of the American Chemical Society, 105 4652-4661 (1983)
Syntheses based on the reaction of Pt(en)34+ with formaldehyde, and ammonia or nitromethane, yielded the macrobicyclic complexes (1,3,6,8,10,13,16,19-octaazabicyclo[6.6.6]icosane)... [more]
Syntheses based on the reaction of Pt(en)34+ with formaldehyde, and ammonia or nitromethane, yielded the macrobicyclic complexes (1,3,6,8,10,13,16,19-octaazabicyclo[6.6.6]icosane)platinum(IV), Pt(sep)4+, and (1,8-dinitro-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane)platinum(IV), Pt(dinosar)4+, respectively. Reduction of the latter complex with SnCl2 in acid yielded (1,8-diamino-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane)platinum(IV), Pt(diamsar)4+. These complexes are substitution-inert, diamagnetic octahedral ions and were characterized by X-ray crystallographic analysis of the Pt(sep)4+ by absorption and NMR spectroscopy. Addition of an electron to the Pt(IV) complexes, radiolytically or electrochemically, yielded transient monomeric macrobicyclic Pt(III) ions. ¿-Radiolysis of crystalline samples yielded a Pt(III) complex stabilized in the crystalline lattice, detected by ESR spectroscopy. Polarography of Pt(diamsar)4+ in aprotic solvents showed essentially irreversible one-electron reductions at +0.17 and -1.00 V and a two-electron irreversible reduction at -2.20 V (in acetone, vs. Ag/AgCl). The Pt(III) transient of the first reduction decayed (t1/2 < 10-3 s) to yield the monodeprotonated Pt(IV) complex and 0.5 mol of hydrogen/mol of complex. The lifetime of the related Pt(sep)3+ transient was longer, though still in the millisecond range. This intramolecular redox process in aprotic solvents was not observed in water, however. In aqueous solution, the Pt(diamsar)3+ transient decayed with a first-order rate constant of 6 × 10-3 s-1 (pH 6.8 or 10.0) in pulse radiolysis experiments. A rate-determining C-N ring opening of the platinum(III) chelate, followed by rapid disproportionation, appears to be the major route for decay of Pt(lll) in aqueous solution. This is supported by voltammetric studies and the detection of both Pt(II) and Pt(IV) macromonocyclic products. © 1983, American Chemical Society. All rights reserved.
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1983 |
Curtis NJ, Lawrance GA, Sargeson AM, 'Base-catalysed linkage isomerization of pentaamminechromium(III) complexes of urea and formamide', Australian Journal of Chemistry, 36 1495-1501 (1983)
The complexes Cr(NH3)5L3+ [L = OCHNH2, OC(NH2)2 and OC(NHMe)2] have been synthesized as the O-bound isomers. At 25°C in aqueous base (pH c. 10-14) they isomerize to the deprotonat... [more]
The complexes Cr(NH3)5L3+ [L = OCHNH2, OC(NH2)2 and OC(NHMe)2] have been synthesized as the O-bound isomers. At 25°C in aqueous base (pH c. 10-14) they isomerize to the deprotonated N-bound isomers without competitive hydrolysis. Reacidification regenerates the O-bound isomer rapidly and completely. The second-order rate constants and pKa values of the amide complexes (I 1.0 m, 25°C) are respectively: 37.01 ± 1.5 dm3 mol-1 s-1 and 11.72 ± 0,06 for formamide; 0.324 ± 0.004 dm3 mol-1 s-1 and 13.50 ± 0.05 for urea; 0.0375 ± 0.0020 dm3 mol-1 s-1 and 14.0 ± 0.2 for N, N¿-dimethylurea. The observations for chromium(III) parallel isimilar behaviour in cobalt(III) and rhodium(III) analogues, but are unusual for chromium(III) chemstry. © 1983 ASEG.
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1983 |
Howlader NC, Haight GP, Hambley TW, Lawrance GA, Rahmoeller KM, Snow MR, 'Structure and Redox Properties of the Molybdenum(IV) Metal Cluster K
The anionic molybdenum(IV) cluster [Mo3S4(CN)9]5- has been subjected to X-ray crystal structure analysis. The potassium salt crystallized in the triclinic space group P1, a 10.634... [more]
The anionic molybdenum(IV) cluster [Mo3S4(CN)9]5- has been subjected to X-ray crystal structure analysis. The potassium salt crystallized in the triclinic space group P1, a 10.634(1), b 11.888(3), c 24.892(2) Å, a 89.56(2), ß 79.86(1), y 76.53(2)°, Z 4. The three MoIV atoms in each unit of approximately C3V symmetry are situated at the corners of an equilateral triangle with Mo-Mo distance 2.765(7) Å. There are three S2- ligands bridging between pairs of Mo atoms, and a unique S2- ligand located uniformly above the plane of the equilateral triangle. Distorted octahedral coordination of each MoIV is completed by three CN- ligands to each of the three metal centres. The ion is structurally similar to the [Mo3S(S2)6]2- precursor, and to [Mo304X9]n- analogues. In dimethyl sulfoxide, the cluster is irreversibly reduced in a single step near -2V(v. saturated calomel electrode), but exhibits a quasi-reversible oxidation at +0.51 V. On the coulometric time scale, the complex is irreversibly oxidized to Mov monomer. © 1983 ASEG.
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1983 |
Bond AM, Lawrance GA, Lay PA, Sargeson AM, 'Electrochemistry of Macrobicyclic (Hexaamine)coball(III) Complexes. Metal-Centered and Substituent Reductions', Inorganic Chemistry, 22 2010-2021 (1983)
The electrochemistry of a wide range of macrobicyclic hexaamine (¿cage¿) and polyamine complexes of coball(III) is reported. All of the substituted [Co(sar)]3+ and [Co(absar)]3+ c... [more]
The electrochemistry of a wide range of macrobicyclic hexaamine (¿cage¿) and polyamine complexes of coball(III) is reported. All of the substituted [Co(sar)]3+ and [Co(absar)]3+ cage complexes exhibit chemically reversible Co(III)/Co(II) couples (sar = sarcophagene = 3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane, absar = 3,6,10,13,15,18-hexaazabicyclo[6.6.5]nonadecane). The Co(II) oxidation state for these complexes is substitutionally inert and undergoes irreversible reduction at very negative potentials in nonaqueous solvents (<-2 V). Quasi-reversible behavior is apparent with all the complexes under study m both aqueous (ClO4- and CF3SO3- media) and nonaqueous (acetone and acetonitnle, CF3SO3- media) solvents. However, in aqueous perchlorate media, at a mercury interface, these reductions are complicated by adsorption processes. The potential of the Co(III)/Co(II) couple is markedly dependent on the nature of substituents on the cage ligand and varies by ~0.6 V for the apically substituted [Co(sar)3+/2+ series. Other factors that influence the potential are preferred cavity size of the cage ligand and outer-sphere medium effects. For each series of structurally similar ligands with constant medium and electrode, the heterogeneous rate constants are the same within experimental erro. In addition to the metal-centered electrochemistry, many of the complexes exhibit redox processes of electroactive organic substituents. These processes are utilized in selected electroorganic syntheses of new cage complexes. The pH dependence of the Co(III)/Co(II) couple is a useful probe to the acidity of various functional groups, and some applications in determining pKa values are described. © 1983, American Chemical Society. All rights reserved.
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1983 |
Dixon NE, Lawrance GA, Lay PA, Sargeson AM, '(TrifluoromethanesuIfonato-O)pentaammine Complexes: Versatile Synthetic Intermediates', Inorganic Chemistry, 22 846-847 (1983)
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1983 |
Boucher HA, Lawrance GA, Sargeson AM, Sangster DF, 'A Pulse Radiolysis Study of (Imidazole)pentaamminecobalt(III) Perchlorate in Water: Ligand to Metal Electron Transfer', Inorganic Chemistry, 22 3482-3484 (1983)
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1983 |
Schwarzenbach G, BÜRgi HB, Lawrance GA, M nsted L, Sargeson AM, Jensen WP, 'Acid Cleavage of Nickel(II) Complexes Containing cis,cis -1,3,5-Cyclohexanetriamine (tach), Crystal Structure of [Ni(tach)(H
The cleavage of [formula-omitted] (tach = cis,cis-1,3,5-cyclohexanetriamine) to give Ni(tach) [formula-omitted] is strictly first order in complex, and no intermediate species has... [more]
The cleavage of [formula-omitted] (tach = cis,cis-1,3,5-cyclohexanetriamine) to give Ni(tach) [formula-omitted] is strictly first order in complex, and no intermediate species has been detected. The observed rate constant is strongly acid dependent, and for HCl and HBF4 the rate law is kobsd = k1/{l + (b + c[H+])-1 + (e + f[H+])-1) with a limiting rate constant k1 = 0.78 ± 0.02 s-1, [formula-omitted] = 72 ± 2 kJ mol-1, and [formula-omitted] = -6 ± 6 J K-1 mol-1 (25 °C, n = 1.0 M). The limiting rate is ascribed to the first Ni-N bond rupture, apparently not involving the chair-boat (skew boat) conformational change of the ligand in the rate-determining step; the acid dependence is traced to a competition between protonation and rechelation of partly dissociated amine ligand. Cleavage in acetate/acetic acid buffers shows that the reaction is catalyzed by acetate and/or acetic acid and that the acid dependence has to be more complex than that indicated above. Cleavage of the Ni-N bonds in acid for Ni(tach)[formula-omitted] is markedly slower than for [formula-omitted] at the same acid concentrations and has a rate law of the form kobsd = k0 + KHX[HX] (25 °C, µ = 3.0 M, k0¿10-5 s-1, HX = HClO4, HCOOH, Cl2CHCOOH, CH3COOH, and [formula-omitted]). The behavior is accommodated by a mechanism similar to that proposed for the bis complex. An X-ray crystallographic analysis of [Ni(tach)(H2O)3](NO3)2 (space group Pnma, Z = 4, a = 14.142 (2) Å, b = 12.637 (2) Å, and c = 8.000 (1) Å) showed the amine coordinated tridentate to the Ni2+ ion with Ni-N distances (2.07 Å) ~0.06 Å shorter than those in [Ni(tach)2](NO3)2; conversely Ni-O distances (2.10 Å) are ~0.05 Å longer than in [formula-omitted]. An analogous trend is observed for the Ni-N and Ni-O distances of [formula-omitted] (n = 1-3); Ni-N and Ni-O bond distances decrease with increasing number of water oxygen atoms in the first coordination sphere. Within each family of complexes the rates of Ni-N or Ni-O bond rupture correlate with bond lengths: short bonds are cleaved more slowly than long bonds. © 1983, American Chemical Society. All rights reserved.
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1983 |
Ali MA, Hay RW, Lawrance GA, 'The preparation and characterisation of Cis-Cobalt(III) complexes of the macrocyclic ligands Me
A large number of cis-complexes of the type cis-[CoL(bidentate)]n+ (L = Me2[14] dieneN4, Me4[14] dieneN4, Me5[14] dieneN4 and Me6[14] dieneN4; bidentate = acac, L-a-ala, gly, bpy,... [more]
A large number of cis-complexes of the type cis-[CoL(bidentate)]n+ (L = Me2[14] dieneN4, Me4[14] dieneN4, Me5[14] dieneN4 and Me6[14] dieneN4; bidentate = acac, L-a-ala, gly, bpy, phen, ox and en) have been prepared and characterised. Rapid inversion of sec-NH centres of the macrocycle in the trans-[CoX2(L)]n+ complexes (X = Cl, Br) occurs in the presence of diethylamine, to give the N-racemic stereochemistry required in the cis-complexes. Infrared, electronic and 1H nmr spectra are reported. © 1983.
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1983 |
Howlader NC, Haight GP, Hambley TW, Lawrance GA, 'Redox properties of potassium µ-thio-bis(hexacyanomolybdate(IV)', Inorganica Chimica Acta, 76 (1983)
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1982 |
Gregory Jackson W, Lawrance GA, Lay PA, Sargeson AM, 'Solvent Dependence, Metal Ion Catalysis and Base Catalysis of Nitrito to Nitro Linkage Isomerization of Pentaamminenitritocobalt(III)', Australian Journal of Chemistry, 35 1561-1580 (1982)
The spontaneous rate of nitrito to nitro isomerization of [(NH3)5CO(ONO)]2+ spans two orders of magnitude for 16 solvents studied. The volume of activation is small and negative (... [more]
The spontaneous rate of nitrito to nitro isomerization of [(NH3)5CO(ONO)]2+ spans two orders of magnitude for 16 solvents studied. The volume of activation is small and negative (from -3·5 to - 7 cm3 mol-1) for water, dimethyl sulfoxide, N-methylformamide and sulfolane. Combined with the observation of negligible competitive solvolysis, and of an isokinetic plot of ¿H¿ against AS¿, this indicates that isomerization is intramolecular in all solvents. The solvent dependence is interpreted in terms of a dual-parameter equation involving terms for the Lewis basicities (DN) and Lewis acidities and polarity (ET). By use of this approach both DN and ET of the solvents are shown to be major contributing factors to reactivity. Further studies on base-catalysed nitrito to nitro isomerizations reveal mild catalysis by F-, AcO- and Et3N in Me2SO. The metal ions Hg2+ Ag+ and Cd2+ also catalyse the isomerization in water [km 1 · 16 × 10-2 dm3 mol-1 s-1, kAg 2·85 × 10-4 dm3 mol-1 s-1, kcd 4·4 × 10-5 dm3 mol-1 s-1; µ 1¿0 M (CIO4-), 25°C]. The lack of competition by AcO-, NO3- and H2O in the Hg2+ -catalysed isomerization reaction also implicates an intramolecular process for this path. In acetone, the ions Hg2+, Ag+, Cd2+ and Zn2+ catalyse the isomerization reaction with a rate law of the form, except for Ag+, where the rate law takes the form, with kAg = kK = 2·11 × 10-3 dm3 mol-1 s-1, k = 1.74 × 10-4 s-1 and K = 12± 1 dm3 mol-1. The limiting rate is ascribed to a high stability constant for the silver adduct intermediate. The analogous RhIII and IrIII complexes also exhibit catalysis by Ag+ and Hg2+ in aqueous solution. © 1982, CSIRO. All rights reserved.
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1982 |
Gahan LR, Lawrance GA, Sargeson AM, 'Branched Cyclononane Macrocycles with Pentaamine and Tetraamine-Thioether Donors. Preparation and Base Hydrolysis of Chlorocobalt(III) Complexes', Australian Journal of Chemistry, 35 1119-1131 (1982)
Synthetic routes to the resolved unsymmetrical (u) isomers of [Co(dats)Cl] (C104)2 [dats = 4,7-bis- (2-aminoethyl)-l-thia-4,7-diazacyclononane] and [Co(datn)Cl] (C104)2 [datn = l,... [more]
Synthetic routes to the resolved unsymmetrical (u) isomers of [Co(dats)Cl] (C104)2 [dats = 4,7-bis- (2-aminoethyl)-l-thia-4,7-diazacyclononane] and [Co(datn)Cl] (C104)2 [datn = l,4-bis(2-aminoethyl)- 1,4,7-triazacyclononane] are reported. The new macrocyclic ligand l-thia-4,7-diazacyclononane (tasn) was synthesized during the former preparation, and the cis-[Co(tasn)2] (C104)3 complex prepared. Base hydrolysis of each chlorocobalt(III) complex proceeds with two consecutive steps. The first reaction in each case is chloride hydrolysis, with kOH(dats) 3¿6 × 104dm3 mol-1 s-1 and k/1(datn) 2¿85 × 103 dm3 mol-1 s-1 at 25°C and 10¿1 M. The second reaction for the dats complex is a base-catalysed dissociation of the thioether to the cis-[Co(dats)(OH)2]+ complex, characterized by 13C n.m.r. experiments, and occurring approximately 20 times slower than chloride hydrolysis. However, the datn complex undergoes a base-catalysed terminal ring opening to the cis-[Co(datn)- (OH)2]+ complex at a rate approximately 30 times slower than chloride hydrolysis. © 1982 ASEG.
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1982 |
Lawrance GA, 'Activation Volumes for Aquation of Cobalt(III) Pentaammine Complexes with Neutral Leaving Groups', Inorganic Chemistry, 21 3687-3691 (1982)
The pressure dependence of the spontaneous aquation of a series of Co(NH3)5L3+ complexes with L = methanol, ethanol, 2-propanol, formamide, N-methylformamide, N,N-dimethylformamid... [more]
The pressure dependence of the spontaneous aquation of a series of Co(NH3)5L3+ complexes with L = methanol, ethanol, 2-propanol, formamide, N-methylformamide, N,N-dimethylformamide, urea, N-methylurea, N,N'-dimethylurea, and dimethyl sulfoxide has been determined. The activation volume (¿V*) lies in the limited range +0.3-+3.8 cm3 mol-1 across the series and is essentially independent of the size of the leaving group. The average ¿V* of ~2 cm3 mol-1 is an estimate of the solvent-independent intrinsic component of ¿V* and is interpreted as being indicative of a dissociative interchange (Id) mechanism. Apparent molar volumes of the series of complexes are reported. The ¿volume profile¿ approach for a dissociative mechanism has been applied to these and earlier data for both neutral and anionic leaving groups; variation in the estimated molar volume of the putative pentacoordinate intermediate with the type of leaving group is discussed in terms of the limited validity of the volume profile approach when an mechanism operates. © 1982, American Chemical Society. All rights reserved.
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1981 |
Dixon NE, Jackson WG, Lancaster MJ, Lawrance GA, Sargeson AM, 'Labile (Trifluoromethanesulfonato)cobalt(III) Amine Complexes', Inorganic Chemistry, 20 470-476 (1981)
Facile synthetic routes to cobalt(III) amine complexes of the labile unidentate trifluoromethanesulfonate anion (CF3SO3-), namely, Co(NH3)5(OSO2CF3)2+, cis-Co(en)2(OSO2CF3)2+, and... [more]
Facile synthetic routes to cobalt(III) amine complexes of the labile unidentate trifluoromethanesulfonate anion (CF3SO3-), namely, Co(NH3)5(OSO2CF3)2+, cis-Co(en)2(OSO2CF3)2+, and fac-Co(dien)(OSO2CF3)3, are reported. The use of these complexes as synthetic precursors for a range of complexes involving direct solvolysis or reactions in poorly coordinating solvents such as sulfolane or acetone is described. For example, in the pentaamminecobalt(III) system, syntheses of Co(NH3)5Ln+ (L = OH2, NH3, OHCH3, OHCH2CH3, OHCH(CH3)2, NCCH3, OP(OCH3)3, OCH.N(CH3)2, OS(CH3)2, OC(NH2)2, NCNH2, -OOCCH3, -OOCCHCl2) in high yield are reported. The kinetics and the stereochemical course of aquation of the labile trifluoromethanesulfonato complexes and derivatives are reported. © 1981, American Chemical Society. All rights reserved.
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1981 |
Lawrance GA, 'Activation volumes for aquation of alcoholpentaamminecobalt(III) ions', Inorganica Chimica Acta, 54 (1981)
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1981 |
Jackson WG, Lawrance GA, Lay PA, Sargeson AM, 'Base-catalyzed linkage isomerization: An undergraduate inorganic kinetics Experiment', Journal of Chemical Education, 58 734-738 (1981)
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1980 |
Lawrance GA, Suvachittanont S, 'The preparation, aquation kinetics and activation volumes of trans-chloro- and trans-bromo- azido(meso-5, 12-dimethyl-1, 4, 8, 11-tetraazacyclo- tetradeca-4, 11-diene)cobalt(iii) perchlorate', Australian Journal of Chemistry, 33 273-278 (1980)
The macrocyclic compexes trans-[Co(dtcd)(N3)X] ClO4 (dtcd = meso-5, 12-dimethyl-1, 4, 8, 11-tetra- azacyclotetradeca-4, 11 -diene; X = Cl- or Br-) have been prepared and character... [more]
The macrocyclic compexes trans-[Co(dtcd)(N3)X] ClO4 (dtcd = meso-5, 12-dimethyl-1, 4, 8, 11-tetra- azacyclotetradeca-4, 11 -diene; X = Cl- or Br-) have been prepared and characterized. Halide aquation in O·1 mHNO3 at 25°C proceeds at rates of 4·6 × 10-4 s-1, ¿H¿ 77(±2) kJ mol-1, ¿S¿ - 51 (±6) J K-1 mol-1 (X = Cl-) and 10·2 × 10-4 s-1, ¿H¿ 80(±3)kJ mol-1, ¿S¿ -34(± 10) J K-1 mol-1 (X = Br-). The pressure dependence of the aquation rate at eevated pressures yields ¿V¿ +8·3(±0·5) cm3 mol-1 (X = Cl-) and ¿V¿ +5·3(±10·7) cm3 mol-1 (X = Br-). While the observed positive ¿V¿ values are consistent with a dissociative mechanism they differ markedly from reported negative ¿V¿ values for acid hydrolysis of [Co(NH3)5X]2+ions. © 1980 Australian Journal of Chemistry.
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1980 |
Lawrance GA, Suvachittanont S, 'Pressure- and temperature-dependent isomerization reactions of aquabis(ethylenediamine)cobalt(III) complexes: Deuterium solvent isotope effects', Australian Journal of Chemistry, 33 1649-1658 (1980)
The pressure and temperature dependence of the trans ¿ cis isomerization reaction of trans- Co(en)2(X)(OH2)n+ (X = OH2, 0Se02H- or AcO-; en = ethane-1, 2-diamine) has been determi... [more]
The pressure and temperature dependence of the trans ¿ cis isomerization reaction of trans- Co(en)2(X)(OH2)n+ (X = OH2, 0Se02H- or AcO-; en = ethane-1, 2-diamine) has been determined in D20, and compared with results previously determined in H2O under analogous conditions of acidity and ionic strength. Generally positive activation volumes (¿V¿) and activation entropies (¿S¿) in both solvents are consistent with a dissociative mechanism with aqua ligand release in the activated state. Isomerization in D20 is characterized by slightly higher ¿H¿ and ¿S¿ values and a less positive ¿V¿ value in each case. The clear change in ¿V¿ from H2O to D2O supports the existence of an appreciable contribution from solvent rearrangement in forming the activated state to the activation volume. Variations in solvent structure and ionic solvation apparently account for the deuterium solvent isotope effect. © 1980, CSIRO. All rights reserved.
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1980 |
Jackson WG, Lawrance GA, Lay PA, Sargeson AM, 'Base-Catalyzed Nitrito to Nitro Linkage Isomerization of Cobalt(III), Rhodium(III), and Iridium(III) Pentaammine Complexes', Inorganic Chemistry, 19 904-910 (1980)
The nitrito ions [M(NH3)5(ONO)]2+ (M = Co(III), Rh(III), or Ir(III)) rearrange to their nitro forms [M(NH3)5(N02)]2+ in aqueous base according to the rate law kobsi = ks + £0h[OH¿... [more]
The nitrito ions [M(NH3)5(ONO)]2+ (M = Co(III), Rh(III), or Ir(III)) rearrange to their nitro forms [M(NH3)5(N02)]2+ in aqueous base according to the rate law kobsi = ks + £0h[OH¿] where at u = 1.0 M, 25.0 °C: ks = 6.9 (±0.2) X 10¿5 s-1, ¿H¿ = 95 ± 4 kJ mol-1, ASs¿ = -4 ± 12 J K-1 mol-1, k0H = 5.9 (±0.2) X 10-6 dm3 mol-1 s-7, ¿H0H¿ = 110 ± 1 kJ moL1, ASoh¿ = +82 ± 4 J K-1 mol-1, M = Co; ks = 9.6 (±0.2) X 10-8 s¿1, ¿H¿ = 85 ± 2.5 kJ moL1, ¿S¿ = -18 ± 9 J K-1 moL1, k0H = 7.6 (±0.2) X 10-3 dm3 mol-1 s-1, ¿Hoh¿ = 96 ± 2 kJ mol-1, ASOH¿ = +38 ± 6 J K-1 mol-1, M = Rh; ks = 3.0 (±0.1) X 10-5 s-1, AHs¿ = 94 ± 2 kJ mol-1, ¿S¿ = 16 ± 5 J K-1 mol-1, k0H = 2.7 (±0.1) X 10-5 dm3 mol-1 s-1, AHoh¿ = 109 ± 2 kJ mol-1, ASoh¿ = 34 ± 6 J K-1 mol-1, M = Ir. For the cobalt complex the pressure dependence of k0h (¿V¿ = +27 (±1.4) cm3 mol-1, ¿d¿ = 5 (±2) cm3- kbar-1 mol-1) points to a conjugate base preequilibrium for the base-catalyzed path. The metal ion dependence of koli/ks (95:9:1 for Co:Rh:Ir) is also consistent with a conjugate base process. [Co(NFl3)5(ONO)]2+ rearranges to [Co(NH3)5(NO2)]2+ without exchange of oxygen with H2180, 18OH]-, or free N18O2- (1 M); both the ks and k0H paths are intramolecular. Up to 1 M OH there is <1% competitive hydrolysis to [M(NH3)5(OH)]2+. Both rate constants ks and k0H for M = Co decrease with increasing ionic strength (25 °C, 105fcs = 6.9, 7.4, 103oh = 5-9, 14.5; u = 1.0, 0.1, respectively), cis- and tram-[Co(en)2(ONO)2]+ and [Co(en)2(ONO)(N02)] + rearrange by both pathways to the dinitro complexes without change in configuration, and (+)cw-[Co(en)2(ONO)(N02)] + rearranges without loss of chirality. For the /c0h reaction these results also differ from the normal substitution chemistry where there is some steric change. In addition to the O to N rearrangement, a much faster O to O scrambling process has been identified for the cobalt complex using lsO tracers. © 1980, American Chemical Society. All rights reserved.
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1980 |
Lawrance GA, O'Connor MJ, Suvachittanont S, Stranks DR, Tregloan PA, 'Pressure-Dependent Racemization Reactions of Tris(Dithiocarbamato)Cobalt(III) Complexes in Nonaqueous Solvents', Inorganic Chemistry, 19 3443-3448 (1980)
The pressure-dependent racemization of Co(pyrdtc)3 (pyrdtc = pyrrolidinecarbodithioate) determined over the pressure range 1-1380 bar yielded activation volumes (¿v*) of +9.8 (±0.... [more]
The pressure-dependent racemization of Co(pyrdtc)3 (pyrdtc = pyrrolidinecarbodithioate) determined over the pressure range 1-1380 bar yielded activation volumes (¿v*) of +9.8 (±0.5) cm3 mol-1 (in ethanol), +5.2 (±0.7) cm3 mol-1 (dimethylformamide), +5.4 (±0.5) cm3 mol-1 (acetonitrile), and +7.8 (±0.6) cm3 mol-1 (toluene). The activation volume in each solvent is pressure dependent; hence nonzero compressibility coefficients of activation (¿ß*) are observed in each solvent. The compressibility of activation (¿k*) is independent of solvent at 0.43 (±0.03) kbar-1. A twist mechanism involving a low-spin ¿ high-spin preequilibrium is proposed on the basis of the experimental data. The Co(Ph2-dtc)3 complex (Ph2-dtc = diphenyldithiocarbamate), by contrast, exhibits negative ¿V* values of between -2 and -9.3 cm3 mol-1 in five different nonaqueous solvents. The alternative one-ended dissociative mechanism is favored for this complex. © 1980, American Chemical Society. All rights reserved.
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1980 |
Jackson WG, Lawrance GA, Sargeson AM, 'Mechanism of Hydrolysis of Substituted Cobalt(III)-Amine Complexes: Pentacoordinate Intermediates?', Inorganic Chemistry, 19 1001-1005 (1980)
The nitrate ion competition and rates of nitrosation of Co(NH3)5N32+ have been measured in NaC104/NaN03 solution over the range of nitrate ion concentration 0-1.0 M (25.0 °C, u = ... [more]
The nitrate ion competition and rates of nitrosation of Co(NH3)5N32+ have been measured in NaC104/NaN03 solution over the range of nitrate ion concentration 0-1.0 M (25.0 °C, u = 1.0 M), yielding a rate law -d[CoN32+]/d; = (fc, + fc2[N03¿])[H+][HN02][CoN32+], One mechanistic model which assumes anion-dependent competition by both the ktand k2 pathways leads to the same competition ratio R for each path (R = [CoN32+]/[CoOH23+][N03~] = 0.405 M-1)-However it is shown that other models lead to an equally good fit of the data. A similar two-term rate law has been reported for the Hg2-induced aquation of Co(NH3)5C12+ in N03- media, 3 and it is demonstrated that an earlier analysis of this rate and competition data is also not unique. One solution requires a five-coordinate intermediate for the path independent of N03- and direct insertion of N03- by Hg2+ ion for the path dependent on N03-. Acceptance of this solution gives the same competition ratio as the nitrosation reaction. Some data are also given which support the direct insertion of anions by the Hg2+-catalyzed path and the problems of interpreting the competition results, and some methods for resolving the ambiguities are discussed. © 1980, American Chemical Society. All rights reserved.
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1980 |
Lawrance GA, 'Activation volumes for aquation of cis-dichlorotetraaminecobalt(III) ions: A view on the molar volume difference between the transition intermediate and precursor complex', Inorganica Chimica Acta, 45 (1980)
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1979 |
Lawrance GA, Stranks DR, 'Role of Activation Volume in the Elucidation of Reaction Mechanisms in Octahedral Coordination Complexes', Accounts of Chemical Research, 12 403-409 (1979)
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1979 |
Lawrance GA, Stranks DR, Suvachittanont S, 'Volumes of Activation for Substitution Reactions of Tris(1,10-phenanthroline)- and Tris(2,2'-bipyridyl)iron(II) Complexes with Hydroxide and Cyanide Ions from High-Pressure Solution Kinetics', Inorganic Chemistry, 18 82-85 (1979)
The effect of high pressure on the rates of substitution of Fe(phen)32+ and Fe(bpy)32+ (phen = 1,10-phenanthroline; bpy = 2,2'-bipyridyl) with hydroxide and cyanide ion has b... [more]
The effect of high pressure on the rates of substitution of Fe(phen)32+ and Fe(bpy)32+ (phen = 1,10-phenanthroline; bpy = 2,2'-bipyridyl) with hydroxide and cyanide ion has been evaluated. All reaction rates are significantly retarded upon the application of pressure. The hydroxide-dependent component of the rate expression exhibits volumes of activation (A¿V¿) of + 19.7 ± 0.3 and +21.5 ± 0.4 cm3 mol-1 for substitution of Fe(phen)32+ and Fe(bpy)32+, respectively. The cyanide-dependent term exhibits ¿V¿ of + 19.8 ± 1.0 and +20.9 ± 1.6 cm3 mol-1 for substitution of Fe(phen)32+ and Fe(bpy)32+, respectively. A rate-determining dissociative interchange mechanism is most consistent with the observation that ¿V¿ for substitution of each complex is positive, pressure-independent, and independent of nucleophile. © 1979, American Chemical Society. All rights reserved.
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1979 |
Lawrance GA, Suvachittanont S, 'Correlation of volumes and entropies of activation for racemization and isomerization reactions of octahedral metal complexes: evidence for a twist mechanism', Inorganica Chimica Acta, 32 (1979)
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1979 |
Lawrance GA, Rix CJ, 'Identification of geometrical isomers of the cobalt(III)-iminodiacetate system - An inorganic laboratory experiment', Journal of Chemical Education, 56 211-212 (1979)
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1979 |
Lawrance GA, Lay PA, 'Some cobalt(III) complexes with coordinated dioxygen and multidentate and cyclic amine ligands', Journal of Inorganic and Nuclear Chemistry, 41 301-304 (1979)
Syntheses of ten binuclear µ-peroxo cobalt(III) complexes with coordinated cyclic tetraamines 5,7-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene and 5,7,7,12,12,14-hexamethyl... [more]
Syntheses of ten binuclear µ-peroxo cobalt(III) complexes with coordinated cyclic tetraamines 5,7-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene and 5,7,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene or chelated diamines and triamines are reported. Absorption maxima of the µ-peroxo and of three µ-superoxo binuclear complexes generated in solution are tabulated. ESR solution spectra of the µ-superoxo binuclear complexes and of a new mononuclear superoxo complex of the cyclic tetraamine rac-5,7,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane are presented. © 1979.
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1979 |
Lawrance GA, Suvachittanont S, Stranks DR, Tregloan PA, Gahan LR, O'Connor MJ, 'Pressure dependence of the racemization of tris(pyrrolidyldithiocarbamato)- cobalt(III) in non-aqueous solvents', Journal of the Chemical Society, Chemical Communications, 757-758 (1979)
From activation volume evidence a twist mechanism incorporating a low-spin ¿ high-spin pre-equilibrium in the transition state is indicated for racemization of Co(pyrdtc)3 (pyrdtc... [more]
From activation volume evidence a twist mechanism incorporating a low-spin ¿ high-spin pre-equilibrium in the transition state is indicated for racemization of Co(pyrdtc)3 (pyrdtc = pyrrolidyldithio-carbamato) in non-aqueous solvents.
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1979 |
Lawrance GA, Suvachittanont S, 'The effect of pressure on the rate of isomerization of acetatoaquobis(ethylenediamine)cobalt(III) perchlorate', Journal of Coordination Chemistry, 9 13-18 (1979)
The isomerization of trans-Co(en)2(acet)(OH2)2+ (en = 1,2-diaminoethane; acet- = acetate anion) in aqueous acid is retarded upon the application of pressure. In 0.05 M HClO4, a pr... [more]
The isomerization of trans-Co(en)2(acet)(OH2)2+ (en = 1,2-diaminoethane; acet- = acetate anion) in aqueous acid is retarded upon the application of pressure. In 0.05 M HClO4, a pressure-independent volume of activation (¿V¿) of +7.9 ± 0.3 cm3 mol-1 is obtained, together with ¿H¿=117.1 ± 3.0 kJ mol-1 and ¿S¿= +61 ± 9 J K-1 mol-1. In 0.05 M HCIO4 with added NaClO4 (I = 1.0 M), ¿V¿= +6.5 ± 0.4 cm3mol-1, ¿H¿ = 112.6 ± 2.4 kJ mol-1 and ¿S¿=+46 ± 7 J K-1 mol-1. In 1.0 M HC1O4, ¿V¿ = +5.6 ±0.6 cm3 mol-1, ¿H¿= 112.9 ± 2.8 kJ mol-1 and ¿S¿= +47 ± 8 J K-1 mol-1. This data is most consistent with isomerization proceeding via dissociative aquo ligand release in a dissociative interchange (Id) mechanism. Analogous Idor D dissociative) mechanisms have been assigned previously to isomerizations of several trans-Co(en)2 (X)(OH2)n+ complexes (X = OH2, SeO3 H- or SeO32-) on the basis of ¿V¿data, and the results for the X = acet¿ complex presented here support a general dissociative mechanism for complexes of this type. © 1979, Taylor & Francis Group, LLC. All rights reserved.
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1978 |
Hawkins CJ, Lawrance GA, Palmer JA, 'Circular Dichroism Spectra of Tetraamminecobalt(III) Complexes of Amino Alcohols', Australian Journal of Chemistry, 31 2399-2408 (1978)
The circular dichroism spectra are reported for tetraamminecobalt(III) complexes with the chiral amino alcohols 2-aminopropan-1-ol, 2-aminobutan-1-ol, l-aminopropan-2-ol, 2-amino-... [more]
The circular dichroism spectra are reported for tetraamminecobalt(III) complexes with the chiral amino alcohols 2-aminopropan-1-ol, 2-aminobutan-1-ol, l-aminopropan-2-ol, 2-amino-1-phenyl- ethanol, ¿-ephedrine and ephedrine with the alcohol groups protonated (OH) and deprotonated (O-). The solvent dependence of the chemical shifts of the NH protons was investigated to determine the effects of stereoselective solvation on the circular dichroism, but, in contrast to some other related systems, the chemical shift difference between the two NH2protons was relatively insensitive to solvent. Consistent with this, the circular dichroism spectra of the tetraphenylborate salts of the deprotonated complexes were found not to be markedly dependent on solvent. Tetraammine- ((-)-¿-ephedrine)cobalt(III) and tetraammine((-)-ephedrine)cobalt(iii) were found to have the same signs of Cotton effects for the various d-d transitions, whereas bis((-)-¿-ephedrine)copper(ii) and bis((-)-ephedrine)copper(ii) had opposite signs. This has been explained in terms of different conformer populations in the cobalt(iii) and copper(ii) systems. © 1978, CSIRO. All rights reserved.
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1978 |
Lawrance GA, Stranks DR, 'Volumes of Activation for Racemization and Aquation of Tris(l, 10-enanthroline) Complexes of Nickel(II) and Iron(II) in Solution', Inorganic Chemistry, 17 1804-1807 (1978)
The effect of high pressure on The rate of racemization and aquation of Ni(phen)32+ and Fe(phen)32+ (en = 1, 10-enanthroline) in solution has been evaluated. Reactions of Fe(phen)... [more]
The effect of high pressure on The rate of racemization and aquation of Ni(phen)32+ and Fe(phen)32+ (en = 1, 10-enanthroline) in solution has been evaluated. Reactions of Fe(phen)32+ exhibit a significant retardation upon the application of pressure, with volumes of activation (¿V¿) of +14.2 and +15.6 cm3 mol-1 for racemization in 0.01 and 1.0 M aqueous HC1, respectively, while aquation in 1.0 M aqueous HC1 exhibits a ¿V¿4 cm3 mo1-1. Possible mechanisms are considered, and a positive contribution to ¿¿xcitation to a high-spin transition state, associated with a general Fe-N bond expansion, is proposed as a component of the mechanism for aquation and racemization. Reactions of Ni(en)32+ show only a minor acceleration of rates upon the application of pressure with ¿V¿ = -0.4 cm3 mol-1 and ¿V¿ = -1.5 cm3 mol-1 for racemization in 0.01 and 1.0 M aqueous HC1, respectively, while aquation in 1.0 M aqueous HC1 exhibits a ¿V¿ of-1.2 cm3 mol-1. A common mechanistic pathway is favored since determined rates and enthalpies and entropies of activation as well as volumes of activation for aquation and racemization are very similar. A dissociative mechanism for release of a en ligand with possible formation in the transition state of a high-spin four-coordinate species of reduced volume compared with the low-spin octahedral precursor is favored from analysis with ¿V¿ data. © 1978, American Chemical Society. All rights reserved. © 1978, American Chemical Society. All rights reserved.
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1978 |
Barraclough CG, Lawrance GA, Lay PA, 'Characterization of Binuclear µ-Peroxo and µ-Superoxo Cobalt(III) Amine Complexes from Raman Spectroscopy', Inorganic Chemistry, 17 3317-3322 (1978)
The Raman spectra of a range of binuclear µ-peroxo and µ-superoxo cobalt (III) complexes with principally amine donor ligands in other coordination sites have been measured in the... [more]
The Raman spectra of a range of binuclear µ-peroxo and µ-superoxo cobalt (III) complexes with principally amine donor ligands in other coordination sites have been measured in the characteristic O-O stretching regions. Monobridged µ-peroxo complexes exhibit a strong resonance Raman band in solution or as solid-state pressed disks at 800±10 cm-1 and monobridged µ-superoxo complexes a band at 1120µ10 cm-1 in solution. These vO2 are generally far stronger than other vibrations of the complexes. Binuclear dicobalt complexes with a second µ-hydroxo or µ-amido bridge in addition to the µ-peroxo or µ-superoxo bridge exhibit relatively weak and generally broad vO2 bands. Dibridged µ-peroxo complexes exhibit the O22- stretch at 812±5 cm-1 in solution and 820 ± 10 cm-1 in the solid state, while dibridged µ-superoxo complexes exhibit the O2- stretch at 1075 ± 10 cm-1. The observation of strong Raman bands near 795 cm-1 for complexes of the macrocyclic tetraamines 5,7,7,12,14,14-hexamethyl-l,4,8,11-tetraazacyclotetradeca-4,ll-diene (Me6[14]diene) and 5,12-dimethyl-1,4,8,1 l-tetraazacyclotetradeca-4,11-diene (Me2[14]diene) supports their characterization as monobridged µ-peroxo-dicobalt (III) complexes and indicates that Raman spectroscopy is useful in the characterization of new binuclear dioxygen complexes. © 1978, American Chemical Society. All rights reserved.
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1978 |
Kendall PL, Lawrance GA, Stranks DR, 'Volumes of Activation for Isomerization and Acid-Catalyzed Aquation Reactions of Diaquobis(oxalato)-and Diaquobis(malonato)chromium(III) Complexes from High-Pressure Studies in Solution', Inorganic Chemistry, 17 1166-1172 (1978)
The effect of high pressure on the rates of isomerization in aqueous perchlorate solutions of trans-[Cr(ox)2(OH2)2]- and trans-[Cr(mal)2(OH2)2]- (ox2- = oxalate; mal2- = malonate)... [more]
The effect of high pressure on the rates of isomerization in aqueous perchlorate solutions of trans-[Cr(ox)2(OH2)2]- and trans-[Cr(mal)2(OH2)2]- (ox2- = oxalate; mal2- = malonate) has been evaluated. The isomerization of trans-[Cr(ox)2(OH2)2]-at pH 3.15 exhibits a volume of activation (¿V¿) of -16.6 cm3mol-1 with a compressibility coefficient of activation (¿ß¿) of -1.8 cm3 mol-2 kbar-1 which is shown to be consistent with isomerization through one-ended dissociation of an oxalato ligand. For the isomerization of trans-[Cr(mal)2(OH2)2]- at pH 3.0, ¿V¿ is +8.9 cm3mol-1 with no measurable ¿ß¿, consistent with a mechanism via dissociative interchange of an aquo ligand. Enthalpies and entropies of activation evaluated for these systems are consistent with these separate mechanisms. The effect of high pressure on the acid-catalyzed aquation of cis-[Cr(ox)2(OH2)2]- and cis-[Cr(mal)2(OH2)2]- in perchloric acid solutions has also been determined. Volumes of activation are ¿V¿ = +1.7 cm3mol-1 for cis-[Cr(ox)2(OH2)2]- and ¿V¿ = +2.4 cm3mol-1 for cis-[Cr(mal)2(OH2)2]- and are consistent with one mechanism operating for both aquation reactions. A mechanism involving direct proton attack at a coordinated carboxylate and subsequent dissociative release of the protonated acid is most consistent with the determined volumes of activation. Enthalpies and entropies of activation were evaluated for each system; the negative ¿S¿ observed for both reactions is also consistent with a common mechanistic pathway. © 1978, American Chemical Society. All rights reserved.
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1978 |
Lawrance GA, Stranks DR, Suvachittanont S, 'Volumes of Activation for Racemization of Mixed 1,10-Phenanthroline and 2,2'-Bipyridyl Complexes of Nickel(II) from High-Pressure Solution Kinetics', Inorganic Chemistry, 17 3322-3325 (1978)
The effect of pressure on the rates of racemization of Ni (phen)2(bpy)2+ and Ni (phen) (bpy)22+ in solution has been evaluated. Reactions of Ni (phen)2(bpy)2+ exhibit only a minor... [more]
The effect of pressure on the rates of racemization of Ni (phen)2(bpy)2+ and Ni (phen) (bpy)22+ in solution has been evaluated. Reactions of Ni (phen)2(bpy)2+ exhibit only a minor pressure dependence of the rate, with a volume of activation (¿V¿) of+0.6 cm3 mol-1 and-0.1 cm3 mol-1 for racemization in 0.01 and 1.0 M aqueous HC1, respectively. Aquation of Ni (phen)2(bpy)2+ in 1.0 M aqueous HC1 exhibits no measurable pressure dependence, with ¿V¿ = 0.0 cm3 mol-1. Racemization of Ni (phen)(bpy)22+ proceeds with a minor acceleration upon the application of pressure, with ¿V¿=-1.9 cm3 mol-1 and ¿V¿=-5.2 cm3 mol-1 in 0.01 and 1.0 M aqueous HC1, respectively. Variation of ¿V¿ with acidity observed suggests an acid-dependent pathway is the dominant mechanism at high acidity but is not important at low acidity. A common mechanistic pathway for racemization and aquation of these complexes is favored since reported rates, enthalpies, entropies and volumes of activation are very similar. A one-ended dissociative mechanism via a half-bonded bpy ligand is consistent with experimental ¿V¿ data. © 1978, American Chemical Society. All rights reserved.
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1977 |
Hawkins CJ, Lawrance GA, Peachey RM, 'Solvent-dependent circular dichroism of trans-disubstituted Bis(R-propane-1,2-diamine)cobalt(III) complexes', Australian Journal of Chemistry, 30 2115-2132 (1977)
The circular dichroism spectra of trans-disubstituted bis(R-propane-1,2-diamine)cobalt(III) complexes are reported for an extended series of solvents. The observed variations in t... [more]
The circular dichroism spectra of trans-disubstituted bis(R-propane-1,2-diamine)cobalt(III) complexes are reported for an extended series of solvents. The observed variations in the spectra of the dichloro and dibromo complexes are analysed in terms of stereoselective solvation at the diamine N-H protons, and also the ion association between the complexes and their counter-ions. The solvation of these dihalo complexes, which was studied by p.m.r., showed a preference for hydrogen-bond formation with the equatorial N-H protons, rendering the donor nitrogens asymmetric and thus introducing a new source of dissymmetry close to the metal ion chromophore. This affected a decrease in the positive rotational strength of the 1A1g {equivalent to} 1Eg (D4h) transition, and a positive contribution to the rotational strength of the 1A1g {equivalent to} 1A2g (D4h) component. Ion association of the dihalo complexes was evaluated by a comparison of the circular dichroism of the tetraphenylborate and halide salts. The tendency for ion association was much greater for the tripositive diammine complex. However, stereospecific solvation was of little importance and the circular dichroism spectra did not show any marked solvent dependence for the tetraphenylborate salt. © 1977, CSIRO. All rights reserved.
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1977 |
Lawrance GA, Stranks DR, 'Volumes of Activation for intramolecular Racemization Mechanisms. High-Pressure Racemization of Bipyridyl, Phenanthroline, and Oxalato Complexes of Chromium(III) in Solution', Inorganic Chemistry, 16 929-935 (1977)
The effect of high pressure on the rates of racemization of metal complexes in solution has been evaluated for the first time. The racemization of Cr(phen)33+ exhibits a volume of... [more]
The effect of high pressure on the rates of racemization of metal complexes in solution has been evaluated for the first time. The racemization of Cr(phen)33+ exhibits a volume of activation, ¿V¿ = +3.3 ± 0.2 cm3 mol-1, which is shown to be consistent with an intramolecular twist mechanism. The racemization of Cr(C2O4)33- exhibits ¿V¿ = -16.3 ± 0.4 cm3mol-1, consistent with racemization through one-ended dissociation of an oxalato ligand. Cr(phen)(C2O4)2- arid Cr(bpy)(C2O4)2- exhibit ¿V¿ = -12.3 ± 0.3 and ¿V¿ = -12.0 ± 0.3 cm3 mol-1, respectively, and these racemizations are assigned a one-ended dissociation mechanism. Cr(phen)2(C2O4)+, Cr(bpy)2(C2O4)+, and Cr(bpy)33+ exhibit ¿V¿ = -1.5 ± 0.2, -1.0 0.1, and +3.4 ± 0.3 cm3 mol-1, respectively, and these are all assigned intramolecular twist mechanism. Enthalpies and entropies of activation were evaluated for all of these systems; ¿H¿ values are least for Cr(C2O4)33- and greatest for Cr(phen)33+ and Cr(bpy)33+ while ¿S¿ values, all large and negative, show the reverse trend. © 1977, American Chemical Society. All rights reserved.
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1977 |
Kendall PL, Lawrance GA, 'The kinetics of the base hydrolysis of trans-Dichloro- and trans-Dibromo-(meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene)cobalt(III) perchlorate', Australian Journal of Chemistry, 30 1841-1845 (1977)
The kinetics of the successive base hydrolysis of both halogen ligands in trans-[Co(hctd)Cl2]+ and trans-[Co(hctd)Br2]+ (hctd = meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyc... [more]
The kinetics of the successive base hydrolysis of both halogen ligands in trans-[Co(hctd)Cl2]+ and trans-[Co(hctd)Br2]+ (hctd = meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) have been investigated at 25°C in formic acid-NaOH buffers (pH range 3.0-3.7) and 2,6-lutidine-perchloric acid buffers (pH range 6.4-7.4). Hydrolysis reactions in each buffer system, consistent with release of first and second coordinated halogen respectively, follow rate expressions of the type kobs = kaq+ kOH]OH-], with base hydrolysis rates kOH' = 7.8(±0.8) x 108 dm3 mol-1 s-1 and 1.9(±0.3)x109 dm3 mol-1 s-1 respectively for first chloride and bromide hydrolysis, and kOH' = 7.3(±0.4)x104 dm3 mol-1 s-1 and 2.4(±0.2)x105 dm3 mol-1 s-1 for second chloride and bromide hydrolysis respectively. Comparison with the analogous complex trans-[Co(dtcd)Cl2]+ (dtcd = meso-5,12-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) shows a ninefold acceleration for base hydrolysis of the first chloride in the hctd complex over the dtcd complex, but an 80-fold rate retardation for base hydrolysis of the second chloride in the hctd complex compared with the dtcd complex, interpreted in terms of steric effects arising from gem-dimethyl substitution in the hctd ligand. © 1977, CSIRO. All rights reserved.
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1976 |
Lawrance GA, Hay RW, 'Kinetics of aquation and base hydrolysis of the macrocyclic complex trans-Bromo(N-meso-5, 12-dimethyl-1, 4, 8, 11-tetraazacyclotetradeca-4, 11-diene)nitro-cobalt(III) perchlorate', Australian Journal of Chemistry, 29 2319-2324 (1976)
The macrocyclic complex trans-[Co(dtcd)(NO2)Br] [ClO4] (dtcd = 5, 12-dimethyl-l, 4, 8, 1l-tetraaza-cyclotetradeca-4, 11-diene) has been prepared and its hydrolysis kinetics invest... [more]
The macrocyclic complex trans-[Co(dtcd)(NO2)Br] [ClO4] (dtcd = 5, 12-dimethyl-l, 4, 8, 1l-tetraaza-cyclotetradeca-4, 11-diene) has been prepared and its hydrolysis kinetics investigated. At 25oC and 0.1 M HN03 the aquation occurs with kaq = 6.2 × 10-3 s-1 to give the trans-Co(dtcd)(NO2)- (OH2)]2+ cation. The activation parameters at 298 K are ¿H = 75.0 kJ mol-1 and ¿S = -35.6 J K-1 mol-1. Hydrolysis of the bromide in the pH range 7.5-8.8 follows the rate expression kobs = kaq + kOH[OH-]. At 25oC (I = 0.1 M, NaClO4) kOH = 1.21 x 103 1. mol-1 s-1 with the activation parameters for base hydrolysis being ¿H = 74.2 kJ mol-1 and ¿S = +63.2 J K-1 mol-1 at 298 K. Aquation and base hydrolysis of the bromo complex at 25oC occur at rates 14 and 5 times faster respectively than those previously reported for the analogous trans-[Co(dtcd)(NO2)Cl]+ complex, the acceleration being due to a more favourable entropy of activation in each case. © 1976 CSIRO.
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1976 |
Barraclough CG, Lawrance GA, 'Evidence for a new µ-peroxo binuclear cobalt(III) complex of a macrocyclic tetramine from Raman spectroscopy', Inorganic and Nuclear Chemistry Letters, 12 133-136 (1976)
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1976 |
Hay RW, Lawrance GA, Shone UR, 'The chemistry of sulphur-nitrogen ligands. Part II. Nickel(II) complexes of the cis-N
The reaction of acetone with the nickel(II) complex of 1,5-bis(2-aminophenylthio)pentane in methanol solution gives the nickel complex of the newmacracyclic title ligand. L1. The ... [more]
The reaction of acetone with the nickel(II) complex of 1,5-bis(2-aminophenylthio)pentane in methanol solution gives the nickel complex of the newmacracyclic title ligand. L1. The complexes [Nil2(L1)]. [Ni(L1)(NCS)2], and [NiBr(ClO4)(L1)] have been prepared by metathesis reactions of [NiBr2(L1)] with an appropriate salt in methanol solution. In the solid state, the electronic spectra and magnetic-susceptibility measurements are consistent with distorted octahedral structuresforthe various complexes. Axial co-ordination is relatively weak; thus [NiBr2(L1)] behaves as a 2: 1 electrolyte in methanol solution.
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1976 |
Hay RW, Galyer AL, Lawrance GA, 'The chemistry of sulphur-nitrogen ligands. Part I. Complex-formation and dealkylation reactions of 1,9-bis(tritylthio)- and 1,9-bis(benzyl-thio)-3,7-diazanonane in the presence of metal(II) salts, and the synthesis of dibromo{3,13-dithia-6,10-diazabicyclo[13.4.0]nonadeca-1(15),16,18-triene} nickel(II)', Journal of the Chemical Society, Dalton Transactions, 939-942 (1976)
The quadridentate N<inf>2</inf>S<inf>2</inf> donor ligands 1,9-bis(tritylthio)-3,7-diazanonane (L<sup>1</sup>) and 1,9-bis(benzylthio)-3,7-diaz... [more]
The quadridentate N<inf>2</inf>S<inf>2</inf> donor ligands 1,9-bis(tritylthio)-3,7-diazanonane (L<sup>1</sup>) and 1,9-bis(benzylthio)-3,7-diazanonane (L<sup>2</sup>) have been prepared as their dihydrobromide salts and allowed to react with metal(II) acetates (M = Ni<sup>II</sup>, Co<sup>II</sup>, and Hg<sup>II</sup>) in methanol solution. Both ligands react with Hg<sup>II</sup> with concomitant dealkylation at the sulphur donor atoms to give a trinuclear complex [Hg(HgL)<inf>2</inf>]Br<inf>2</inf>·3H<inf>2</inf>O (L = 3,7-diazanonane-1,9-dithiolato). Treatment of this complex (dissolved in aqueous HCl) with H<inf>2</inf>S gives the dihydrochloride of 3,7-diazanonane-1,9-dithiol. Dealkylation does not occur in the presence of Co<sup>II</sup>, the isolated complexes in this case being blue tatrahedral [CoL<sup>1</sup>]Br<inf>2</inf> and purple octahedral [CoBr<inf>2</inf>(L<sup>2</sup>)]. Nickel(II) gives the blue octahedral [NiBr<inf>2</inf>(L<sup>2</sup>)], but catalyses rapid detritvlation of L<sup>1</sup> to give the black. <inf>1</inf>diamagnetic, trinuclear complex [Ni(NiL)<inf>2</inf>]Br<inf>2</inf>. Reaction of [Ni(NiL)<inf>2</inf>]Br<inf>2</inf>, with a,a'-dibromo-o-xylene in methanol solution gives blue dibromo{3,13-dithia-6,10-diazabicyclo[ 13.4.0]nonadeca-1(15),16,18-triene}nickel(II).
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1976 |
Hay RW, Lawrance GA, 'Kinetics of hydrolysis of trans-dichloro- and trans-dibromo-(n-meso-5,12-dimethyl-1,4,8,11-tetra-azacyclotetradeca-4,11-diene) cobalt(III) cations', Journal of the Chemical Society, Dalton Transactions, 1086-1089 (1976)
The kinetics of hydrolysis of the title cations trans-[CoX2(N-meso-L4)]+ (X = Cl or Br; L4 = 5,12-dimethyl-1,4,8,11-tetra-azacyclotetradeca-4,11-diene) have been studied at I = 0.... [more]
The kinetics of hydrolysis of the title cations trans-[CoX2(N-meso-L4)]+ (X = Cl or Br; L4 = 5,12-dimethyl-1,4,8,11-tetra-azacyclotetradeca-4,11-diene) have been studied at I = 0.1 mol dm-3 over the range pH 3.0-4.5. Hydrolysis of the first halogen ligand obeys a rate expression of the form kobs. = kOH2 + k1OH[OH-], where kobs. is the observed first-order rate constant at constant pH. The values of k1OH are 8.5 × 107 (X = Cl)and ca. 1 × 109 dm3 mol-1 s-1 (X = Br) at 25 °C. The base-hydrolysis rates are the highest yet reported for halogenocobalt(III) complexes of the [CoX2(N4)]2+ type. Ths pH-independent process is represented by kOH2 = 5.4 × 10-3 s-1 for the chloro-complex. Hydrolysis of the second halogen ligand proceeds more slowly and in this case kobs. = k2OH[OH-] with k2OH = 5.9 × 106 (X = Cl) and 1.2 × 107 dm3 mol-1 s-1 (X = Br) at 25 °C. The thermodynamic activation parameters for the hydrolysis of the second halogen ligand are ¿H¿ = 57 kJ mol-1 and ¿S298¿ = 75 J K-1 mol-1 (X = Cl) and ¿H¿ = 56 kJ mol-1 and ¿S298¿ = 80 J K-1 mol-1 (X = Br). These values may indicate rate-determining deprotonation of the substrate in the base-hydrolysis reactions.
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1975 |
Hay RW, Lawrance GA, 'Kinetics of aquation and base hydrolysis of the macrocyclic complex trans-chloro(5,12-dimethyl-1,4,8,11-tetra-azacyclotetradeca-4,11-diene) nitrocobalt(III) perchlorate', Journal of the Chemical Society, Dalton Transactions, 1556-1559 (1975)
The macrocyclic complex trans-[Co(dtcd)(NO<inf>2</inf>) Cl][ClO<inf>4</inf>] (dtcd = 5,12-dimethyl- 1,4,8,11 -tetra-azacyclotetradeca-4,11 -diene) has been... [more]
The macrocyclic complex trans-[Co(dtcd)(NO<inf>2</inf>) Cl][ClO<inf>4</inf>] (dtcd = 5,12-dimethyl- 1,4,8,11 -tetra-azacyclotetradeca-4,11 -diene) has been prepared and its hydrolysis kinetics investigated. At 25 °C and 0.1 M-HNO<inf>3</inf> the aquation occurs with k<inf>aq</inf> = 4.4 × 10<sup>-4</sup> s<sup>-1</sup> to give the trans-[Co(dtcd)(NO<inf>2</inf>)(OH<inf>2</inf>)]<sup>2+</sup> cation. The activation parameters are ¿H<sup>¿</sup> = 77.4 kJ mol<sup>-1</sup> and ¿S<sup>¿</sup> = -49.8 J K<sup>-1</sup> mol<sup>-1</sup> at 298 K. Hydrolysis of the chloride in the pH range 7.7-8.9 follows the rate expression k<inf>obs.</inf> = k<inf>aq</inf> + k<inf>2</inf>[OH<sup>-</sup>]. At 25 °C (I = 0.1 M Na[ClO<inf>4</inf>]) k<inf>2</inf> = 2.5 × 10<sup>2</sup> l mol<sup>-1</sup> s<sup>-1</sup> and the activation parameters for base hydrolysis are ¿H<sup>¿</sup> = 69 kJ mol<sup>-1</sup> and ¿S<sup>¿</sup> = +24.5 J K<sup>-1</sup> mol<sup>-1</sup>. Base hydrolysis of the nitro-group has been studied at 25 °C and 0.1 M-NaOH and k = 2.1 l mol<sup>-1</sup> s<sup>-1</sup>. Slow decomposition of the complex occurs, possibly as a result of hydrolysis of the imine linkages; however, this decomposition (k<inf>oba.</inf> = 2.2 × 10<sup>-3</sup> s<sup>-1</sup>) is much slower than nitro-hydrolysis. The analogous complex trans-[Co(htcd)(NO<inf>2</inf>)Cl] [ClO<inf>4</inf>] (htcd = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetra-azacyclotetradeca-4,11-diene) exhibits similar kinetic behaviour for base hydrolysis of the chloride. At 25 °C (I = 0.1M), k<inf>2</inf> = 2.2 × 10<sup>2</sup> l mol<sup>-1</sup> s<sup>-1</sup> and k<inf>aq</inf> = 5.5 × 10<sup>-4</sup> s<sup>-1</sup>. The additional methyl substituents in the macrocyclic ligand have little or no effect on the hydrolysis rates.
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1975 |
Hay RW, Gidney PM, Lawrance GA, 'Cobalt(III) complexes of 3,7-dithianonane-1,9-diamine', Journal of the Chemical Society, Dalton Transactions, 779-783 (1975)
A convenient synthetic route to the ligand 3,7-dithianonane-1,9-diamine (dtnd) has been developed. A series of cobalt(III) complexes, [Co(dtnd)Cl2]+, [Co(dtnd)O3C]+, [Co(dtnd) (NO... [more]
A convenient synthetic route to the ligand 3,7-dithianonane-1,9-diamine (dtnd) has been developed. A series of cobalt(III) complexes, [Co(dtnd)Cl2]+, [Co(dtnd)O3C]+, [Co(dtnd) (NO2)2]+, [Co(dtnd)(NO2)Cl]+, [Co(dtnd)-(NO2)Br]+, [Co(dtnd)(ox)]+ (ox = oxalate), with a variety of anions have been prepared and characterised. The cis-complexes have the cis-ß-configuration in contrast to the complexes of 3,6-dithiaoctane-1,8-diamine (dtod) which give only the cis-a-isomers. In the case of [Co(dtnd)Cl2]+, both the cis-ß- and the trans-isomers can be prepared. In the complex [Co(dtnd) (NO2)2]+, one nitro-group is readily replaced by Cl- or Br- on treatment with the appropriate mineral acid. A recent crystal-structure determination on the complex [Co(dtnd)(NO2)Cl]Cl has shown that the nitro-group trans to the sulphur atom is displaced. The complex has the cis-ß-configuration with the six-membered chelate ring in the chair conformation. The sulphur centres have the same chirality. N.m.r., i.r., and electronic spectra of the complexes are discussed.
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1973 |
Hawkins CJ, Lawrance GA, 'Circular dichroism spectra of N, N-dimethyl-L-amino acids', Australian Journal of Chemistry, 26 1801-1803 (1973)
The circular dichroism spectra in the region 190-300 nm have been measured at pH 1 and pH 13 in aqueous solution for a series of N, N-dimethyl-L-amino acids. A dominant positive C... [more]
The circular dichroism spectra in the region 190-300 nm have been measured at pH 1 and pH 13 in aqueous solution for a series of N, N-dimethyl-L-amino acids. A dominant positive Cotton effect is generally observed between 205 and 225 nm as has been found previously for the parent L-amino acids. These results are consistent with the same conformer being dominant for both series of compounds. © 1973, CSIRO. All rights reserved.
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1973 |
Hawkins CJ, Lawrance GA, 'Circular dichroism spectra of asymmetric unidentate amine complexes of cobalt(III)', Australian Journal of Chemistry, 26 2401-2407 (1973)
The preparations of pentaamminecobalt(III) complexes of a series of asymmetric unidentate amines are reported. The circular dichroism spectra for the (S)-amines show negative Cott... [more]
The preparations of pentaamminecobalt(III) complexes of a series of asymmetric unidentate amines are reported. The circular dichroism spectra for the (S)-amines show negative Cotton effects under the 1A1g ¿ 1T1g absorption band, which are somewhat solvent dependent but independent of temperature down to -190°C. The vicinal effect from 1-cyclohexylethylamine was comparable to that from analogous aromatic compounds, but the simpler alkyl derivatives were found to impose smaller rotational strengths on the d-d transitions. The lack of measurable c.d. in the visible region for tetraammine((S)-butane-1, 3-diamine)cobalt(III) is reported and discussed in the light of the other studies. © 1973, CSIRO. All rights reserved.
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1973 |
Hawkins CJ, Lawrance GA, 'Circular dichroism of pentaamminecobalt(III) complexes of asymmetric a-substituted ethylamines', Inorganic and Nuclear Chemistry Letters, 9 483-485 (1973)
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1973 |
Hawkins CJ, Lawrance GA, 'Circular dichroism of tetraaminecobalt(III) complexes of asymmetric bidentate chelates', Inorganic and Nuclear Chemistry Letters, 9 1183-1187 (1973)
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1971 |
Hawkins CJ, Lawrance GA, 'Circular dichroism spectra of 2-substituted propionatopentaaminocobalt(II) complexes', Australian Journal of Chemistry, 24 2275-2280 (1971)
The preparations of a series of optically active complexes with the general formula Co(NH2)5(OCOCH(X)CH3)2+ are reported for X = NH3+, OH, F, Cl, Br, C2H5, and C6H5. The circular ... [more]
The preparations of a series of optically active complexes with the general formula Co(NH2)5(OCOCH(X)CH3)2+ are reported for X = NH3+, OH, F, Cl, Br, C2H5, and C6H5. The circular dichroism spectra of the complexes have been measured in aqueous solution, in the presence of salts of polarizable anions, and in KBr disks. The spectra have been analysed in terms of three Cotton effects under the 1A1g ¿ 1T1g cubic absorption band and found to be consistent with a +, -, - sign pattern for the L-isomer, corresponding to the two components of the 1A1g ¿ 1Eg (D4h) and to the 1A1g ¿ A2g(D4h) transition, respectively. © 1971 CSIRO. All rights reserved.
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