No description available.

Aptamers are synthetic nucleic acid molecules designed to bind with high specificity and affinity to a selected target. The aptamer selection method, called the systematic evolution of ligands by exponential enrichment (SELEX), was first described in 1990 and has been adapted for the selection of aptamers for a number of applications. One such application is the selective targeting of cells for therapeutic delivery. This thesis explores this application with the selection and characterisation of internalising aptamers specific to the T lymphocyte specific receptor, CD7. The CD7 receptor is expressed on thymus derived progenitor lymphocytes and remains after T cell activation and expression of the CD4 receptor. As such, the CD7 receptor is a noteworthy target for lymphocyte cancers, HIV-1 and other T lymphocyte tropic viruses. A heterogeneous pool of internalising CD7-aptamers was enriched through six rounds of positive selection in a stably transduced CD7-HeLa cell line. Aptamers were selected using a modified whole cell SELEX method that selected specifically for internalising aptamers. Aptamer specificity for CD7-HeLa cells over HeLa cells was screened by flow cytometry. CD7 specific aptamers were screened for binding after blocking CD7-HeLa cells with an anti-CD7 antibody. Eight CD7 specific aptamer clones were selected from CD7-HeLa screening for evaluation in Jurkat cells (T lymphocyte cell line endogenously expressing the CD7 receptor). Three aptamer clones showed high level binding to Jurkat cells by flow cytometry (CSIR 3.14, CSIR 3.37 and CSIR 3.42). Kinetic analysis of aptamer internalisation was analysed using flow cytometry and determined to be within the femtomolar range. Aptamer CSIR 3.14 had a dissociation constant of 2.1 fM and an association rate of 4.7 ± 2.4 × 105 Molar-1minute-1, aptamer CSIR 3.37 had a dissociation constant of 0.23 fM and an association rate of 4.3 ± 3.3 × 106 Molar-1minute-1 and aptamer CSIR 3.42 had a dissociation constant of 1.1 fM with an association rate of 7.9 ± 5.1 × 105 Molar-1minute-1. Aptamer CSIR 3.14 internalisation was tracked by confocal microscopy and the kinetics calculated with an association rate of 6.3 × 104 Molar-1minute-1 and Kd of 13 fM. Deletions within the CSIR 3.14 sequence that altered the predicted structures significantly reduced the aptamer binding. Combined, the data presented in this thesis identifies aptamer CSIR 3.14 as a lymphocyte specific internalising aptamer with potential for therapeutic delivery.

Both products, n-butyraldehyde and iso-butyraldehyde from propene hydroformylation are key building blocks for the synthesis of many chemical intermediates, and although high linear selectivity has been achieved, any form of branched selectivity remains very difficult to attain. This project aims to deliver a catalyst that can selectively produce branched iso-butyraldehyde as the major product from propene hydroformylation. One approach discussed is to study terphenyl phosphines as ligands. The synthesis of substituted terphenyls through Suzuki-Miyaura coupling reactions between aryl boronic acids and 2,6-dichloroanisole was studied. Novel phosphine-phosphanamine ligands with bulky terphenyl substituents were synthesised and tested in propene hydroformylation, and also asymmetric hydroformylation of other alkenes. The synthesis of several ferrocene-based phosphine-phosphoramidite ligands is also discussed. These ligands were then tested in rhodium-catalysed propene hydroformylation and their reactivities and selectivities are reported. These ligands/Rh catalysts showed a moderate reactivity for propene hydroformylation and up to 56% branched selectivity, which is close to the best selectivity known under industrially relevant conditions. The introduction of bulky substituents on the phosphoramidite part of the ligand did not deliver any huge increases in regioselectivity, but a large improvement in catalyst thermal stability was observed in experiments conducted using in situ high pressure infrared spectroscopy. The reaction conditions for rhodium-catalysed propene hydroformylation using the BOBPHOS ligand were investigated, with unprecedented branched selectivity of up to 82% achieved. A variety of aspects was examined, including the solvent, reaction temperature, reaction pressure with varying partial pressure of CO and H₂, and rhodium to ligand ratio. BOBPHOS derivatives which are more synthetically accessible and economically attractive were synthesised and tested in rhodium-catalysed propene hydroformylation. Comparable results with their parent ligand/Rh catalyst were obtained and improved thermal stabilities were observed in selected catalysts. Different directions for potential future works are suggested, which hopefully, along with the findings in this thesis, can be a major contribution to the development of an efficient, branched selective catalytic system for industrial propene hydroformylation.

Hui Cheng. / "September 1999." / Thesis (Ph.D.)--Chinese University of Hong Kong, 1999. / 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.

by Wing-Fong Law. / Year shown on spine: 1997. / The "2" in the title is subscript. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 103-110). / ACKNOWLEDGMENT --- p.i / CONTENTS --- p.ii / LIST OF FIGURES --- p.v / LIST OF TABLES --- p.vii / ABBREVIATIONS --- p.viii / ABSTRACT --- p.x / Chapter I. --- STUDIES OF OCTASUBSTITUTED OXO(PHTHALOCYANINATO) TITANIUM(IV) COMPLEXES / Chapter 1. --- INTRODUCTION --- p.2 / Chapter 2. --- RESULTS AND DISCUSSION / Chapter 2.1. --- Preparation of Substituted Dicyanobenzenes and Dicyanonaphthalene --- p.9 / Chapter 2.2. --- Synthesis of Octasubstituted Oxo(phthalocyaninato)titanium(IV) and (Naphthalocyaninato)oxotitanium(IV) Complexes --- p.12 / Chapter 2.3. --- "Solvent Effects on the UV-Vis Absorption Spectra of (2,3,9,10,16, 17,23,24-Octaheptylphthalocyaninato)oxotitanium(IV)" --- p.27 / Chapter 2.4. --- Aggregation of Octasubstituted Oxo(phthalocyaninato)titanium(IV) and (Naphthalocyaninato)oxotitanium(IV) Complexes --- p.29 / Chapter 2.5. --- Electrochemical Studies of Octasubstituted Oxo(phthalocyaninato)- titanium(IV) and (Naphthalocyaninato)oxotitanium(IV) Complexes --- p.34 / Chapter 2.6. --- Reactions of Disubstituted Dicyanobenzenes with Zirconium(IV) Butoxide and Urea --- p.39 / Chapter 2.7. --- Conclusion --- p.40 / Chapter 3. --- EXPERIMENTAL SECTION / Chapter 3.1. --- Materials --- p.42 / Chapter 3.2. --- Physical Measurements --- p.42 / Chapter 3.3. --- "Preparation of l,2-Dicyano-4,5-diheptylbenzene" --- p.43 / Chapter 3.4. --- "Preparation of l,2-Dicyano-4,5-bis(pentyloxy)benzene" --- p.45 / Chapter 3.5. --- "Preparation of l,2-Dicyano-4,5-bis(alkoxymethyl)benzene" --- p.47 / Chapter 3.6. --- "Preparation of 3,6-Bis(butyloxy)-l,2-dicyanobenzene" --- p.49 / Chapter 3.7. --- "Preparation of 2,3-Dicyano-5,8-dihexylnaphthalene" --- p.50 / Chapter 3.8. --- Preparation of Octasubstituted Oxo(phthalocyaninato)titanium(IV) Complexes --- p.52 / Chapter 3.9. --- Preparation of Octasubstituted (Naphthalocyaninato)oxotitanium(IV) Complex --- p.57 / Chapter 3.10. --- Miscellaneous Syntheses --- p.58 / Chapter II. --- dioxotungsten(vi) complexes with n202 and n2s2 tetradentate ligands / Chapter 1. --- INTRODUCTION --- p.62 / Chapter 2. --- RESULTS AND DISCUSSION / Chapter 2.1. --- Preparation of Tetradentate Ligands --- p.75 / Chapter 2.2. --- Preparation of Dioxotungsten(VI) Complexes --- p.78 / Chapter 2.3. --- Electrochemical Studies of Dioxotungsten(VI) Complexes --- p.86 / Chapter 2.4. --- Oxo-transfer Properties of Dioxotungsten(VI) Complexes --- p.91 / Chapter 2.5. --- Conclusion --- p.94 / Chapter 3. --- EXPERIMENTAL SECTION / Chapter 3.1. --- Materials --- p.95 / Chapter 3.2. --- Physical Measurements --- p.95 / Chapter 3.3. --- Preparation of Tetradentate Ligands --- p.96 / Chapter 3.4. --- Preparation of Dioxotungsten(VI) Complexes --- p.100 / REFERENCES --- p.103 / APPENDIX A lH NMR spectra of Pc'TiOs --- p.111 / APPENDIX B 13C{1H} NMR spectra of octasubstituted PcTi compounds --- p.113 / APPENDIX C Mass spectra of octasubstituted PcTi and PcZr compounds --- p.118 / "APPENDIX D IR spectra of octasubstituted PcTi, NcTi and PcZr compounds" --- p.124 / APPENDIX E Cyclic voltammograms of octasubstituted PcTiOs and NcTiO --- p.131 / APPENDIX F Determination of aggregation number (n) and aggregation constant (K) --- p.136 / APPENDIX G 1H NMR spectra of dioxotungsten(VI) complexes --- p.138 / APPENDIX H 13C{1H} NMR spectra of dioxotungsten(VI) complexes --- p.140 / APPENDIX I LSI mass spectra of dioxotungsten(VI) complexes --- p.143 / APPENDIX J IR spectra of dioxotungsten(VI) complexes --- p.147 / APPENDIX K Crystallographic data of W02(L2-N202) (64) --- p.150 / APPENDIX L Kinetic data for the oxo-transfer reactions --- p.160

Lam Tai Wing. / Thesis submitted in: December 2001. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaf 75). / Abstracts in English and Chinese. / Abstract --- p.i / 中文摘要 --- p.iii / Acknowledgements --- p.v / Contents --- p.vi / List of Compounds Synthesized --- p.ix / List of Abbreviations --- p.x / Chapter CHAPTER 1 --- Development of Bis(l-azaallyl) Ligands in Organometall Chemistry of Group 4 Transition Metals --- p.ic / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.1.1 --- General aspects of group 4 transition metal complexes containing azallyl Ligands --- p.1 / Chapter 1.1.2 --- Objective --- p.7 / Chapter 1.2 --- Results and Discussion --- p.12 / Chapter 1.2.1 --- Preparation and characterization of pyrazyl-linked bis(l-azaallyl) dilithium complexes --- p.12 / Chapter 1.2.2 --- Attempted preparation of pyrazyl-linked bis(l-azaallyl) dipotassium complex --- p.14 / Chapter 1.2.3 --- "Molecular structures of pyrazyl-linked bis(l-azaallyl) dilithium complexes [{{C(H)(SiMe3)}2C4H2Nr2，3} {Li2(TMEDA)2}]2 (25) and [{{N(SiMe3)C(But)C(H)}2C4H2N2-2,3} {Li2(THF)2}]2 (27)……" --- p.15 / Chapter 1.3 --- Experimental Section --- p.20 / References / Chapter CHAPTER 2 --- "Synthesis, Reactivity and Characterization of Transition Metal Complexes Containing 1-Azaallyl Ligands" / Chapter 2.1 --- Introduction --- p.32 / Chapter 2.2 --- Results and Discussion --- p.36 / Chapter 2.2.1 --- Preparation and Characterization of [Zr{C(SiMe3)2C5H4N-2}2(CH3)Cl (36) and [Hf{C(SiMe3)2C5H4N-2}2(CH3)2] (37) --- p.36 / Chapter 2.2.2 --- Molecular Structure of [Zr{C(SiMe3)2C5H4N-2}2(CH3)Cl (36) and [Hf{C(SiMe3)2C5H4N-2}2(CH3)2] (37) --- p.38 / Chapter 2.2.3 --- Preparation and Characterization of [Zr{N(SiMe3)C(But)C(H)(C5H4N-2)}2(CH3)2] (41) and [Hf{N(SiMe3)C(But)C(H)(C5H4N-2)}2(CH3)2] (42) --- p.40 / Chapter 2.2.4 --- Molecular Structure of [Zr{N(SiMe3)C(But)C(H)(C5H4N-2)}2(CH3)2] (41) and [Hf{N(SiMe3)C(But)C(H)(C5H4N-2)}2(CH3)2] (42) --- p.42 / Chapter 2.2.5 --- "Preparation and Characterization of [Zr{{N(SiMe3)C(But)C(H)}2C6H4-l,2}](CH3)Cl] (44) and [Hf{{N(SiMe3)C(But)C(H)}2C6H4-l,2}]Cl2] (45) and [Hf{{N(SiMe3) C(But)C(H)}2C6H4-l,2}](CH3)Cl](46)" --- p.45 / Chapter 2.2.6 --- "Molecular Structures of [Zr{{N(SiMe3)C(But)C(H)}2C6H4-l ,2}] (CH3)C1] (44), [Hf{{N(SiMe3)C(But)C(H)}2C6H4-l,2}]Cl2] (45) and [Hf{{N(SiMe3)C(But)C(H)}2C6H4-l,2}](CH3)Cl] (46)" --- p.47 / Chapter 2.2.7 --- "Attempted reaction of [Hf{ {N(SiMe3)C(But)C(H)}2C6H4-l,2}]Cl2] with 2 equivalents of KMe" --- p.52 / Chapter 2.2.8 --- Preparation and Characterization of [Ni {N(SiMe3)C(But)C(H) (C5H4N-2)}2] (47) --- p.52 / Chapter 2.2.9 --- Molecular Structures of [Ni {N(SiMe2CH2)C(But)C(H)(C5H4N-2)}2] (47) --- p.53 / Chapter 2.3 --- Experimental Section --- p.57 / References --- p.67 / Chapter CHAPTER 3 --- Catalytic Activity Studies of 1-Azaallyl Group 4 Metal Dimethyl Complexes in Ethylene Polymerization / Chapter 3.1 --- Introduction --- p.69 / Chapter 3.2 --- Results and Discussion --- p.71 / Chapter 3.3 --- Experimental Section --- p.73 / Chapter 3.4 --- Attempted isolation of zwitterionic complexes of 1-azaallyl group4 complexes --- p.74 / References --- p.75 / APPENDIX I / Chapter A --- General Experimental Procedures and Physical Measurement --- p.76 / Chapter B --- X-ray Crystallography --- p.76 / APPENDIX II / Crystallographic Data and Refinement Parameters --- p.78

Chapter 1 focuses on the computational study of Zr(CH2Ph)4 and chapter 2 discusses synthesis, characterization and density functional study of 2-imidazolethione. Chapters 3 - 6 describe the synthesis, structural characterization several multidentate tripodal ligands, namely tris(mercaptoimidazolyl)-hydroborato ligand, [TmR], tris(2-pyridylseleno)methyl ligand, [Tpsem], bis(2-pyridonyl)(pyridine-2-yloxy)methyl ligand, [O-poBpom] and allyl-tris(3-t-butylpyrazolyl)borato ligand, [allylTpBut], and their application to main group and transition metals. Chapter 1 describes the analysis of a monoclinic modification of Zr(CH2Ph)4 by single crystal X-ray diffraction, which reveals that the Zr-CH2-Ph bond angles in this compound span a range of 25.1°; that is much larger than previously observed for the orthorhombic form (12.1°;). In accord with this large range, density functional theory calculations demonstrate that little energy is required to perturb the Zr-CH2-Ph bond angles in this compound. Furthermore, density functional theory calculations on Me3ZrCH2Ph indicate that bending of the Zr-CH2-Ph moiety in the monobenzyl compound is also facile, thereby demonstrating that a benzyl ligand attached to zirconium is intrinsically flexible, such that its bending does not require a buffering effect involving another benzyl ligand. Chapter 2 describes the structure of 1-t-butyl-1,3-dihydro-2H-benzimidazole-2-thione which has been determined by X-ray diffraction. The compound exists in the chalcogenone form instead of chalcogenol form, which is similar to its oxo and selone counterparts. Comparison of 2-imidazolone, 2-imidazolethione and 2-imidazoleselone compounds shows that two N-C-E bond angles in the chalcogenone forms are not symmetric. This trend can be reproduced by density functional theory calculations. Additionally, H(mbenzimBut) has intermolecular hydrogen bonding interactions, whereas its selenium counterpart does not. The C-E bond lengths of 2-imidazolone, 2-imidazolethione and 2-imidazoleselone compounds are intermediate between those of formal C-E single and double bonds, which is in accord with the notion that zwitterionic structures that feature single C+-E- dative covalent bonds provide an important contribution in such molecules. Furthermore, NBO analysis of the bonding in H(ximBut) derivatives demonstrates that the doubly bonded C=E resonance structure is most significant for the oxygen derivative, whereas singly bonded C+-E- resonance structures dominate for the tellurium derivative. This result appears to be counterintuitive, based on the fact that it opposes the trend that one would expect on the basis of electronegativity difference, however, studies on XC(E)NH2 derivatives provide solid support for it. In this regard, the C~E bonding in these compounds is significantly different to that in chalcogenoformaldehyde derivatives for which the bonding is well represented by a H2C=E double bonded resonance structure. Chapter 3 describes the computational study on [TmMeBenz] anion and the synthesis and characterization of [TmButBenz]Na, [TmButBenz]Tl and [TmButBenz]Tl. It is worth noting that the two thallium compounds are the first structurally characterized monovalent monomeric [TmR]Tl complexes. Chapter 4 describes the synthesis and characterization of a few [TmR]M (M = Ti, Zr, Hf) complexes, including (i) Cp[TmBut]TiCl2 and Cp[TmBut]ZrCl2, which are analogues of Cp2TiCl2 and Cp2ZrCl2; (ii) [TmBut]Zr(CH2Ph)3 and (iii) [TmBut]Hf(CH2Ph)3 and [TmAd]Hf(CH2Ph)3, which are the first structurally characterized [TmR]Hf complexes. Chapter 5 describes two multidentate, L3X type ligands, which feature [CN3] and [CNO2] donors, namely tris(2 pyridylseleno)methane, [Tpsem]H, and bis(2-pyridonyl)(pyridin-2-yloxy)methane, [O-poBpom]H. They have been synthesized, characterized, and employed in the synthesis of zinc and cadmium complexes. Chapter 6 describes the synthesis and structural characterization of a new [Tp] ligand featuring an allyl substituent on the central boron atom, namely [allylTpBut]Li is reported. The compound reacts steadily with CH3CH2SH under 350 nm UV light via a thiol-ene click reaction. The resulting [CH3CH2S(CH2)3TpBut]Li complex can further react with metal halide. For example, the reaction of [CH3CH2S(CH2)3TpBut]Li with ZnI2 produced [CH3CH2S(CH2)3TpBut]ZnI at room temperature. This study provides a simple model on the immobilization of [Tp] metal complexes to the polymer chains with -SH terminals.

The molecular structures of [κ³-S₂H-Tmᴮᵘᵗ]Na(THF)₃ and [κ³-S₂H-Tmᴬᵈ]Na(THF)₃ have been obtained, which is significant as these are the first two examples of monomeric κ³-S₂H coordinate sodium compounds to be reported. Based on an extensive structural analysis of all of the [Tmᴿ]M compounds listed in the Cambridge Structural Database, a set of criteria has been generated that can be used to classify [Tmᴿ] ligands according to their coordination modes. Compounds exhibiting κ³-S₃ coordination are found to be the most prevalent, as are compounds exhibiting 0:3 conformation modes. A series of [Tmᴮᵘᵗ]CdO₂CR complexes (R = C₆H₄-4-Me; C₆H₄-4-F; C₆H₃-3,5-F₂; C₆H₃-2,6-F₂; C₃H₆Ph; 9-An; and tridecyl) has been prepared via the reaction of [Tmᴮᵘᵗ]CdMe with the corresponding carboxylic acids. [Tmᴮᵘᵗ]ZnO₂CR (R = C₆H₄-4-Me; C₆H₄-4-F; C₆H₃-3,5-F₂; C₆H₃-2,6-F₂; 9-An) have been prepared by an analogous method. In addition, two thiobenzoate complexes, [Tmᴮᵘᵗ]MSC(O)Ph (M = Zn, Cd), have been obtained via the treatment of [Tmᴮᵘᵗ]MR (R = Me) with thiobenzoic acid. An extensive structural analysis of the [Tmᴮᵘᵗ]MO₂CR and [Tmᴮᵘᵗ]MSC(O)Ph complexes has been provided, based on single crystal X-ray diffraction and NMR spectroscopy. In addition, degenerate benzoate exchange between [Tmᴮᵘᵗ]MO₂C(4-C₆H₄-F) and 4-fluorobenzoic acid has been investigated by ¹⁹F-NMR lineshape analysis over a large temperature range (195-262 K). The acid concentration dependence of the rate for the exchange process supports an associative exchange mechanism. [Tmᴮᵘᵗ]MO₂C(4-C₆H₄-F) benzoate exchange is extremely rapid on the 19F NMR timescale at 25˚, and has been observed to be faster for [Tmᴮᵘᵗ]CdO₂C(4-C₆H₄-F) than for [Tmᴮᵘᵗ]ZnO₂C(4-C₆H₄-F). The reactivity of [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) towards different thiols, ArSH (Ar = C₆H₄-4-F, C₆H₄-4-Buᵗ, C₆H₄-4-OMe, C₆H₄-3-OMe), has been investigated using various NMR techniques. In contrast to the results of our degenerate benzoate exchange studies, thiolate exchange between [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) and ArSH is slow on the ¹H NMR timescale. Even at elevated temperatures, the NMR signals for the reaction species remain resolved with minimal linebroadening. The equilibrium constants for the reactions of [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) with ArSH (Ar = C₆H₄-4-But, C₆H₆-4-OMe, C₆H₄-3-OMe) have been calculated and determined to be indistinguishable, with equilibrium favoring the [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) and ArSH species. Additionally, the reactivity of [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) toward phenols, ArOH (Ar = Ph, 2,6-diphenylphenol), has been investigated. While [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) has been found to be unreactive toward ArOH, [Tmᴮᵘᵗ]CdSOAr (Ar = 2,6-diphenylphenol) reacts immediately (C₆H₄-4-F)SH, resulting in complete conversion to [Tmᴮᵘᵗ]CdS(C₆H₄-4-F). Two monomeric [Tmᴮᵘᵗ]CdE(2-C₅H₄N) complexes (E = S, Se) have also been prepared, and structurally characterized. A monomeric, terminal zinc hydride complex, [Tmᴮᵘᵗ]ZnH, has been prepared via the reaction of [Tmᴮᵘᵗ]ZnOPh with phenylsilane. The molecular structure of [Tmᴮᵘᵗ]ZnH has been obtained by single crystal X-ray diffraction techniques, and the reactivity of [Tmᴮᵘᵗ]ZnH towards various reagents has been investigated. [Tmᴮᵘᵗ]ZnH reacts rapidly with ArEH (EAr = OPh, S(C₆H₄-4-F), SePh) to form [Tmᴮᵘᵗ]ZnEA via H₂ elimination. [Tmᴮᵘᵗ]ZnH reacts with CO₂ to form [Tmᴮᵘᵗ]ZnO₂CH via CO₂ insertion into the Zn-H bond. [Tmv]ZnO₂CH can also be prepared by the reaction of [Tmᴮᵘᵗ]ZnH with formic acid. [Tmᴮᵘᵗ]ZnH reacts rapidly with ZnEt₂ to form [Tmᴮᵘᵗ]ZnEt. The reaction of [Tmᴮᵘᵗ]ZnH with CpMo(CO)₃H resulted in the formation of a metal-metal bonded complex, namely [Tmᴮᵘᵗ]Zn-MoCp(CO)₃. A series of [Tmᴮᵘᵗ]M-M'Cp(CO)₃ heterobimetallic complexes (M = Zn, Cd; M' = Cr, Mo, W) has been prepared via the reaction of [Tmᴮᵘᵗ]MR (R = Me) with CpM'(CO)₃H. An extensive structural analysis of these complexes is provided, based on X-ray diffraction and NMR spectroscopy. Each of these complexes features a direct M-M' bond, which is supported by two partially bridging carbonyl ligands. Only a few complexes featuring an M-M' bond have been structurally characterized, and the molecular structures of [Tmᴮᵘᵗ]Zn-CrCp(CO)₃ and [Tmᴮᵘᵗ]Cd-WCp(CO)₃ represent the first two structures reported for compounds featuring either a Zn-Cr or Cd-W bond. The coordination chemistry of [tpyᴬʳ] (Ar = p-tolyl, mesityl) and [bppᴮᵘᵗ] with various main group and transition metals has been investigated. [tpyᴬʳ]MX₂ complexes (M = Co, Zn; X = Cl, I) are prepared by the reaction of [tpyᴬʳ] with the dihalide MX2 complex. [bppᴮᵘᵗ]MX2 (M = Fe, Co, Zn, Cd; X = Cl, I) complexes are prepared by an analogous method. Each of these [tpyᴬʳ]MX₂ and [bppᴮᵘᵗ]MX₂ complexes have been characterized by single crystal X-ray diffraction. The [bppᴮᵘᵗ]LiI compound was unexpectedly obtained from the reaction of [bppᴮᵘᵗ]FeCl₂ with MeLi, which is significant as it is the first example of an alkali metal complex featuring a [bppᴮᵘᵗ] ligand that has been structurally characterized.

Ce travail s'articule autour d'une méthode originale d'élaboration de ligands polydentes à motifs phosphine-carbène N-hétérocyclique (NHC) basée sur la réactivité unique de complexes du manganèse(I) à ligands méthylènephosphonium CpMn(CO)2(eta2-R2P+=C(H)Ph) vis-à-vis de dérivés de l'imidazole judicieusement choisis. Le premier chapitre consiste en une mise au point sur les ligands polydentes associant une phosphine à un carbène N-hétérocyclique, leur variété, leurs méthodes de synthèse et leurs applications dans le domaine de la catalyse homogène. Le deuxième chapitre est consacré à la synthèse d'une variété de complexes de méthylènephosphonium CpMn(CO)2(eta2-R2P+=C(H)Ph) à partir du cymantrène CpMn(CO)3 et de phosphines secondaires HPR2 portant différents groupements sur l'atome de phosphore dont le dérivé 2,5-diphénylphospholane disponible en version optiquement active. Les études spectroscopiques, structurales et théoriques ont permis de comprendre la structure électronique des complexes de méthylènephosphonium et de rationaliser leur réactivité vis-à-vis des nucléophiles qui s'avère être en effet être opposée à celle des sels de méthylènephosphonium libres. Le troisième chapitre décrit la préparation d'une bibliothèque de pré-ligands de type phosphine-C(H)Ph-imidazolium par attaque nucléophile d'un imidazole substitué (ImR') sur des complexes méthylènephosphonium suivie d'une étape de démétallation des complexes de phosphine intermédiaires CpMn(CO)2(kappa1-R2P-C(H)Ph-Im+R') par irradiation dans le visible et en solution dans le dichlorométhane. Selon la nature du substituant porté par l'azote de l'imidazole, cette approche a permis d'obtenir de manière directe et efficace des pré-ligands bidentes (R' = alkyl ou aryl), pinces à cœur NHC portant des bras divers (pyridine, thioéther, NHC ou ylure de phosphonium) ou même des architectures tétradentes de type bis-NHC-bis-phosphine. Le quatrième chapitre est consacré à des études préliminaires de chimie de coordination de ces nouveaux ligands avec des métaux de transition de première (Mn, Ni, Cu) et deuxième (Rh, Pd) ligne du tableau périodique. En particulier, il est montré que le ligand tridente phosphine-NHC-pyridine peut être coordonné au métal soit dans un mode classique de type pince pour le complexes de RhI, RhIII et NiII, soit selon un mode de coordination pontant non-conventionnel entre deux atomes métalliques connectés par une interaction métallophile (CuI) ou une liaison covalente (Mn0). Le cinquième chapitre est centré sur la synthèse d'une nouvelle famille de complexes ylure de phosphore métallasubstitué-NHC obtenus par déprotonation sélective du lien benzylidène dans des complexes incorporant des ligands bidentes R2P-C(H)Ph-NHC. Ce type de complexes, isolés en série PdII et MnI, peuvent activer facilement la liaison C-H de l'acétonitrile ou la liaison H-H du dihydrogène, respectivement, illustrant un nouveau mode de coopération métal-ligand. Ce dernier processus a été exploité en série MnI en catalyse d'hydrogénation de cétones. / This work is based on an original method for the elaboration of phosphine- N-heterocyclic carbene (NHC) polydentate ligands based on the unique reactivity of methylenephosphonium manganese (I) complexes CpMn(CO)2(eta2-R2P+=C(H)Ph) with imidazole derivatives judiciously chosen. The first chapter focuses on the polydentate ligands associating a phosphine with an N-heterocyclic carbene, their variety, their methods of synthesis and their applications in the field of homogeneous catalysis. The second chapter is dedicated to the synthesis of a variety of methylenephosphonium complexes CpMn(CO)2(eta2-R2P+=C(H)Ph from cymantrene CpMn(CO)3 and secondary phosphines HPR2 carrying different groups on the phosphorus atom whose 2,5-diphenylphospholane derivative available in optically active version. Spectroscopic, structural and theoretical studies have made it possible to understand the electronic structure of methylenephosphonium complexes and to rationalize their reactivity towards nucleophiles, which turns out to be in contrast to that of free methylenephosphonium salts. The third chapter describes the preparation of a library of phosphine-C(H)Ph-imidazolium pre-ligands by nucleophilic attack of a substituted imidazole (ImR') on methylenephosphonium complexes followed by a step of demetallation of intermediate phosphine complexes CpMn(CO)2(kappa1-R2P-C(H)Ph-Im+R') by irradiation in the visible and in solution in dichloromethane. Depending on the nature of the substituent carried by the imidazole nitrogen, this approach has made it possible to directly and efficiently obtain bidentate pre-ligands (R' = alkyl or aryl), NHC core pincers carrying various arms (pyridine, thioether, NHC or phosphonium ylide) or even tetradentate architectures of bis-NHC-bis-phosphine type. The fourth chapter is devoted to preliminary studies of coordination chemistry of these new ligands with transition metals of first (Mn, Ni, Cu) and second (Rh, Pd) periodic table line. In particular, it is shown that the phosphine-NHC-pyridine trident ligand can be coordinated to the metal either in a conventional pincer mode for the RhI, RhIII and NiII complexes, or in a non-conventional bridging coordination mode between two metal atoms connected by a metallophilic interaction (CuI) or a covalent bond (Mn0). The fifth chapter focuses on the synthesis of a new family of metallasubstituted phosphorus ylide-NHC complexes obtained by selective deprotonation of the benzylidene bond in complexes incorporating R2P-C(H)Ph-NHC bidentate ligands. This type of complex, isolated in series PdII and MnI, can easily activate the C-H bond of acetonitrile or the H-H bond of dihydrogen, respectively, illustrating a new mode of metal-ligand cooperation. This last process was exploited in series MnI in catalysis of hydrogenation of ketones.

Song Haibin. / "March, 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 137-151). / 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.