No description available.

No description available.

Bimolecular rate constants for the quenching of up to 15 excited triplet aromatic hydrocarbons by eight S-diketonate complexes of Cr(III) and four of Co(III) have been obtained using nanosecond laser flash photolysis. The bimolecular rate constants have been plotted against donor energy and for those quenchers whose rate constants follow the available spectroscopic energy levels in the quencher, electronic energy transfer is established to be the mechanism of quenching. As the electrochemical reduction potential of the quencher is reduced by the introduction of trifluoromethyl groups into the S-diketonate complexes, an increase in quenching efficiency is observed which may be explained by modifying the mechanism of quenching to include electron transfer. Theoretical models have been developed in order to predict quenching constants for the different mechanistic pathways. For the quenching of excited triplet states by y-substituted chromium (III) complexes, rate constants greater than those predicted by the Debye Equation, once spin statistics have been introduced, were obtained. Diffusion theories were examined and a Spernol-Wirtz type treatment was employed,since this takes into account microfiction between solute and solvent molecules of differing molecular radii. Using this diffusion theory allowed all of the results presented to be interpreted within the framework of the theoretical models. The effect of geometrical isomerism on the quenching efficency of a chromium(III) complex was investigated and it was found that the aisisomers is a more efficient electronic energy transfer quencher than the trans form, especially when energy is being accepted by the quartet state. The general nature of the approach developed in the thesis was examined by measuring the quenching rate constants for four Co(III) a-diketonate complexes.

No description available.

Chapter One introduces the principle of alkoxide and phosphine oxide as ligands for lanthanides and electropositive metals, ligand self-recognition, stereoselective polymerisation of lactide, fixation of CO2 and finally copolymerisation of CO2 and epoxide. Chapter Two shows the synthesis of the proligands rac-HLR (a racemic phosphine oxide-alkoxide, A, where R = tBu, Ph or C6H3-Me-3,5) and explores the resolution into diastereomeric RRR- and SSS-M(LR)3 to afford C3–symmetric M(LR)3 complexes, B (where M = Sc, Lu, Y, In, Bi or La). It also demonstrates that the process is under thermodynamic control and driven by ligand self-recognition via the synthesis of bis(LR) adducts (LR)2MX, C, (where M = Y or In and X = N(SiMe3)2 or OC6H3-tBu2-2,6) and mono(LR) adducts (LR)MX2, D (where M = Al or In and X = N(SiMe3)2, CH2SiMe3 or Me). Finally, it outlines the fixation of CO2 into an indiumamide bond. Chapter Three contains a detailed investigation of the potential of the MIII complexes as initiators for the stereoselective polymerisation of lactide, - caprolactone, glycolide and copolymerisation of lactide and -caprolactone, lactide and glycolide and CO2 and epoxide. Chapter Four investigates the use of rac-HLtBu in the resolution into diastereomeric RR- and SS-M(LtBu)2 complexes, E (where M = Ca, Zn or Sn), and of rac-HLPh into [M(LR)2]2 complexes, F (where M = Mg, Co or Sn and R = Ph or C6H3-Me-3,5) and mono-(LtBu) adducts (LtBu)MgX, G (X = N(SiMe3)2 or OC6H3-tBu2-2,6). It also describes the synthesis of protonated MII complexes (HLR)MCl2, H (where M = Mg, Zn or Sn and R = tBu or Ph). Finally, it details the polymerisation of lactide and its copolymerisation with glycolide using MII complexes as initiators. Chapter Five gives full experimental details and analytical data for the herein described novel compounds.

M.Sc. / Since the discovery of Ni(CO)4 by Mond in 1890, many chemists became interested in organometallic chemistry. This field of research expanded after the synthesis of ferrocene in 1951. organometallic complexes are widely used in organic synthesis, especially as catalysts ...

by Chi-Shing Chan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 62-65). / Acknowledgements --- p.i / Contents --- p.ii / Abbreviations --- p.iii / Abstract --- p.1 / Introduction --- p.2-8 / Synthetic Strategy --- p.9-12 / Results and Discussion / Chapter A. --- Synthesis of the aryl triflate substituted and aryl bromide substituted porphyrins --- p.13-15 / Chapter B. --- Synthesis of the (alkynyl)phenyl substituted porphyrins --- p.16-19 / Chapter C --- Benzannulation of Fischer carbene complexes with (alkynyl)phenyl substituted porphyrins --- p.20-23 / Chapter D. --- "Palladium-catalysed cross coupling reaction of 2,5-dimethoxyphenyl boronic acid with aryl triflate or aryl bromide substituted porphyrins" --- p.24-28 / Chapter E. --- Synthesis of the meso-tetrakis(benzoquinonyl) porphyrin --- p.29 / Chapter F. --- Metalation of the quinone-linked porphyrins --- p.30 / Chapter G. --- Preliminary study on the electrocatalytic activity of the quinone-linked metalloporphyrin complexes of cobalt and palladium for the electrochemical reduction of carbon dioxide --- p.31 / Conclusion --- p.32 / Experimental --- p.33-61 / References --- p.62-65 / List of spectra / Porphyrin aryl triflate4 --- p.66 / (Alkynyl)phenyl porphyrin 9 d --- p.67 / Tetra(quinonyl)phenyl porphyrin 12a --- p.68 / (Naphthoquinonyl)phenyl porphyrin 13b --- p.69 / "2,5 -dimethoxyphenyl boronic acid 16" --- p.70 / (Benzoquinonyl)phenyl porphyrin19 --- p.71 / Tetra(quinonyl)phenyl porphyrin 23 --- p.72

Peng Yu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / Abstracts in English and Chinese. / Table of Contents --- p.i / Acknowledgements --- p.iv / Abstract --- p.v / Abbreviations --- p.ix / Chapter CHAPTER 1. --- METALLATION OF AMINOPYRIDINE AND AMINOQUINOLINE / Chapter 1.1 --- INTRODUCTION / Chapter 1.1.1 --- General Background --- p.1 / Chapter 1.1.2 --- Synthesis of Metal Amides --- p.2 / Chapter 1.1.3 --- General Review of Lithium Amido Complexes --- p.4 / Chapter 1.1.4 --- Structures of Some Potassium and Sodium Amido Complexes --- p.8 / Chapter 1.1.5 --- A Brief Review of TV-functionalized Amido Metal Complexes --- p.9 / Chapter 1.1.6 --- Objective of This Work --- p.13 / Chapter 1.2 --- RESULTS AND DISCUSSION / Chapter 1.2.1 --- Synthesis of N-functionalized Amido Ligands --- p.14 / Chapter 1.2.2 --- Lithiation of Aminopyridine --- p.15 / Chapter 1.2.3 --- Lithiation of Aminoquinoline --- p.17 / Chapter 1.2.4 --- Attempted Synthesis of Sodium Amido Complexes --- p.19 / Chapter 1.2.5 --- Attempted Synthesis of Potassium Amido Complexes --- p.19 / Chapter 1.2.6 --- Physical Characterizations of and Compounds 1-10 --- p.20 / Chapter 1.2.7 --- "Molecular Structures of Compounds 3，4, 7, 8, and10" --- p.24 / Chapter 1.3 --- EXPERIMENTALS FOR CHAPTER 1 --- p.37 / Chapter 1.4 --- REFERENCES FOR CHAPTER 1 --- p.44 / Chapter CHAPTER 2. --- SYNTHESIS AND STRUCTURES OF GROUP12 AMIDO COMPLEXES / Chapter 2.1 --- INTRODUCTION / Chapter 2.1.1 --- General Review of Zinc(II) Amido Complexes --- p.49 / Chapter 2.1.2 --- General Review of Cadmium(II) Amido Complexes --- p.53 / Chapter 2.1.3 --- General Review of Mercury(II) Amido Complexes --- p.56 / Chapter 2.2 --- RESULTS AND DISCUSSION / Chapter 2.2.1 --- Synthesis of Homoleptic Zinc(II) Amido Complexes --- p.58 / Chapter 2.2.2 --- Attempted Reaction of Compounds [Zn(L1)2] and [Zn(L3)2] (11) with ArSH and S --- p.59 / Chapter 2.2.3 --- Attempted Reaction of [Zn(L1)Cl] with ArSLi and ArMe OLi --- p.59 / Chapter 2.2.4 --- Synthesis of Cadmium(II) Amido Complexes --- p.61 / Chapter 2.2.5 --- "Attempted Reaction of [{Cd(L3)2}2(tmeda)] (16) with S， Se, and ArSH" --- p.63 / Chapter 2.2.6 --- "Attempted Reaction of [Cd(L3)2] (15) with 4,4'- bipyridine" --- p.64 / Chapter 2.2.7 --- Synthesis of Mercury(II) Amido Complexes --- p.65 / Chapter 2.2.8 --- "Reaction of [Hg(L3)2] (21) with S, Se, and ArSH " --- p.67 / Chapter 2.2.9 --- Physical Characterizations of Compounds 11-23 --- p.68 / Chapter 2.2.10 --- "Molecular Structures of Compounds 11, 13, 16, and 21" --- p.73 / Chapter 2.3 --- EXPERIMENTALS FOR CHAPTER 2 --- p.84 / Chapter 2.4 --- REFERENCES FOR CHAPTER 2 --- p.94 / Chapter CHAPTER 3. --- SYNTHESIS AND STRUCTURES OF COPPER AND SILVER(I) AMIDO COMPLEXES / Chapter 3.1 --- INTRODUCTION / Chapter 3.1.1 --- Overview of Transition Metal Amides --- p.99 / Chapter 3.1.2 --- General Review of Copper Amido Complexes --- p.101 / Chapter 3.1.3 --- General Review of Silver(I) Amido Complexes and their Derivatives --- p.105 / Chapter 3.2 --- RESULTS AND DISCUSSION / Chapter 3.2.1 --- Synthesis of Homoleptic Copper(I) Amido Complexes --- p.108 / Chapter 3.2.2 --- Reaction of [{Cu(L3)}2] (24) with ArSH and Dioxygen --- p.110 / Chapter 3.2.3 --- Synthesis of Homoleptic Copper(II) Amido Complexes --- p.111 / Chapter 3.2.4 --- Attempted Reaction of CuCl2 with [{Li(L4)}3] (8) --- p.112 / Chapter 3.2.5 --- Attempted Reaction of [Cu(L3)2] (24) with ArSH --- p.112 / Chapter 3.2.6 --- Synthesis of Silver(I) Amido Complexes --- p.113 / Chapter 3.2.7 --- Attempted Reaction of AgN03 with [{Li(L4)}3] (8) --- p.114 / Chapter 3.2.8 --- Physical Characterizations of Compounds 24-29 --- p.115 / Chapter 3.2.9 --- "Molecular Structures of Compounds 24, 25, 26, and28" --- p.119 / Chapter 3.3 --- EXPERIMENTALS FOR CHAPTER 3 --- p.131 / Chapter 3.4 --- REFERENCES FOR CHAPTER 3 --- p.138 / Chapter CHAPTER 4. --- SYNTHESIS AND STRUCTURES OF NICKEL(II) AMIDO COMPLEXES / Chapter 4.1 --- INTRODUCTION / Chapter 4.1.1 --- General Review of Nickel Derivatives --- p.139 / Chapter 4.2 --- RESULTS AND DISCUSSION / Chapter 4.2.1 --- Synthesis of Homoleptic Nickel(II) Amido Complexes --- p.144 / Chapter 4.2.2 --- Attempted Reaction of NiCl2 with [Li(L3)(tmeda)] (3) --- p.145 / Chapter 4.2.3 --- Physical Characterizations of Compounds 30-32 --- p.145 / Chapter 4.2.4 --- Molecular Structures of Compounds 31 and 32 --- p.147 / Chapter 4.3 --- EXPERIMENTALS FOR CHAPTER 4 --- p.153 / Chapter 4.4 --- REFERENCES FOR CHAPTER 4 --- p.155 / Chapter APPENDIX 1 --- General Procedures and Physical Measurements --- p.157 / Chapter APPENDIX 2 --- "Table A-1. Selected Crystallographic Data for Compounds 3, 4, 7, and 8" --- p.160 / "Table A-2. Selected Crystallographic Data for Compounds 10, 11, 13，and 16" --- p.161 / "Table A-3. Selected Crystallographic Data for Compounds 21, 24, 25, and 26" --- p.162 / "Table A-4. Selected Crystallographic Data for Compounds 28，31, and 32" --- p.163

Investigations into the Physical Properties and Reactivity of Thorium(III) Complexes: A thesis submitted to The University of Manchester for the degree of Doctor of Philosophy in the Faculty of Science and Engineering. Since the first full structural characterisation of a thorium(III) complex 30 years ago, the chemistry of the highly reactive oxidation state has been largely neglected with respect to related uranium(III) chemistry. Despite the employment of nuclear technologies across the globe since the 1950's, the relatively poor understanding of the actinides is somewhat surprising, in particular the models used to describe their bonding. Herein, this work presents an investigation into the reactivity of a thorium(III) complex, [Th(Cp'')3] (Cp'' = {C5H3(SiMe3)2-1,3}-); the synthesis and full characterisation of a new thorium(III) complex, [Th(Cptt)3] (Cptt = {C5H3(tBu)2-1,3}-); and the synthesis of two new hexadentate trisanilido ligands which are shown to stabilise uranium(III) and offer highly flexible coordination modes. All of the compounds presented were characterised via a range of analytical and spectroscopic techniques. [Th(Cptt)3] is shown to react with a series of small molecules, displaying elevated reactivity in the majority of cases to the similar uranium(III) complexes. In this work, [Th(Cptt)3] is shown to activate: P4, pyridine, 4,4'-bipyridine, Ph2CO, MeCN, CS2 and CO2, to form dimeric thorium(IV) complexes. The reactivity studies presented provide the first real measure of the reductive capability of the thorium(III) oxidation state. The first pulsed EPR spectroscopy experiments on actinide containing complexes are reported for a pair of new complexes, [M(Cptt)3] (M = U, Th), with the results allowing the direct calculation, via measurement of hyperfine coupling constants, of bonding between the actinide elements and the supporting ligand framework. The results indicate that comparative covalent character is found for the studied actinide complexes with the only other f-element complex characterised by this technique, [Yb(Cp)3], challenging conventional bonding models.

Cheuk Wai So. / "June 2003." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.