by Huichang Zhang. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 114-130). / Acknowledgment --- p.i / Abstract --- p.ii / Abbreviations --- p.iii / Table of Contents --- p.iv-v / Chapter Chapter I --- Introduction --- p.1 / Chapter I --- The basis of asymmetric catalysis --- p.6 / Chapter II --- Chiral catalyst --- p.8 / Chapter II-I --- Center metal --- p.9 / Chapter II-II --- Chiral ligand --- p.10 / Chapter III --- Structural analysis of effective chiral ligands --- p.13 / Chapter III-I --- Monodentate ligand --- p.15 / Chapter III-II --- Bidentate Ligand --- p.16 / Chapter 1 --- Bidentate phosphine ligand --- p.16 / Chapter 2 --- Bidentate oxygen ligand --- p.17 / Chapter 3 --- Bidentate nitrogen ligand --- p.19 / Chapter 4 --- "Bidentate ligand with N, 0，P, or S donor atom" --- p.21 / Chapter III-III --- Potentially tridentate ligand --- p.22 / Chapter III-IV --- Potentially tetradentate ligand --- p.23 / Chapter IV --- Tentative conclusions on the effect of structural elements --- p.24 / Chapter Chapter II --- "Design, synthesis and resolution of novel chiral pyridylphenols" --- p.27 / Chapter I --- Design of chiral ligand --- p.27 / Chapter II --- Synthesis of chiral ligands --- p.29 / Chapter II-I --- "Synthesis of the chiral N, O-donor ligands" --- p.29 / Chapter 1 --- Synthesis of the chiral ligands 75a-75c --- p.29 / Chapter 2 --- Synthesis of the chiral ligands 93a and 93b --- p.37 / Chapter 3 --- Synthesis of the chiral ligands 97a-97c --- p.41 / Chapter II-II --- "Synthesis of the chiral N, P-donor ligand 98 and N, S-donor ligand 101" --- p.42 / Chapter III --- Resolution of racemates of chiral ligands --- p.44 / Chapter III-I --- Resolution of of the pyridylphenol 75b --- p.44 / Chapter III-II --- Resolution of of the pyridylphenol 93a --- p.48 / Chapter III-III --- Racemization study of 75b and 93a --- p.52 / Chapter 1 --- Racemization test of 75b --- p.52 / Chapter 2 --- Racemization test of 93a --- p.52 / Chapter Chapter III --- Asymmetric addition of diethylzinc to aromatic aldehydes catalyzed by chiral pyridylphenols / Chapter I --- Backgound --- p.53 / Chapter II --- Asmmetric addition of Et2Zn to aldehydes catalyzed by chiral pyridylphenols --- p.61 / Chapter II-I --- Asmmetric addition of Et2Zn to aldehydes catalyzed by (R)-(+)-75b --- p.61 / Chapter 1 --- The influence of the solvent --- p.61 / Chapter 2 --- The influence of the reaction temperature --- p.64 / Chapter 3 --- The influence of the concentration of catalyst --- p.66 / Chapter 4 --- Electronic effect on the enantioselectivity of asymmetric addition of Et2Zn to aromatic aldehydes --- p.67 / Chapter II-II --- Asmmetric addition of Et2Zn to aldehydes catalyzed by (5)-(+)-75b --- p.73 / Chapter II-III --- Asmmetric addition of Et2Zn to aldehydes catalyzed by (R)-(+)-93a --- p.75 / Chapter III --- Conclusions --- p.78 / Chapter Chapter V --- Experimental Section --- p.79 / References --- p.114 / NMR Spectra --- p.131

by Fuk Yee Kwong. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2000. / 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.

published_or_final_version / Chemistry / Master / Master of Philosophy

Chapter 1 contains an Introduction to the role of metal complexes in functional assemblies. The remainder of the chapter is devoted to an Introduction to the

Since Swiatoslaw Trofimenko first reported their synthesis in 1966, poly(pyrazolyl)borate ligands, [R”ₓB(pz，ᴿ⋅ᴿ’)₄₋ₓ], have found widespread utility in modern coordination chemistry, undoubtedly as a consequence of the numerous facets of the ligand scaffold that can be readily altered. Relative to the extensive efforts directed towards the incorporation of pyrazolyl moieties with different substituents and towards the installation of groups other than hydrogen on the bridgehead boron, comparatively few attempts have been dedicated to elucidating synthetic approaches to altering the identity of the bridgehead atom itself. Such manipulations have the potential to generate new compounds that exhibit both structural and electronic properties previously unobserved or inaccessible for the parent boron compound, and the research summarized herein is motivated both by the paucity of these derivatives and by this potential. Chapter 1 explores the use of aluminum and gallium as linker atoms to afford heavier congeners of traditional poly(azolyl)borates. This study has utilized LiEH₄ (E = Al, Ga) in place of LiBH₄, and significantly has afforded the first structurally characterized examples of tris(pyrazolyl)hydrogallates and of tris(pyrazolyl)methylgallates featuring substituted pyrazolyl groups. Moreover, the structures of {[R”ETpᴿ⋅ᴿ’]Li}₂ (E = Al, Ga) have been found to vary as a consequence of the identity of both the pyrazolyl substituents (R, R’) and the substituent on the linker atom (R”), and in some instances differ significantly from the structures of the corresponding boron derivatives. Additionally, the reactions of LiEH4 with tert-butylmercaptoimidazole, HmimBut, have afforded the first examples of tris(mercaptoimidazolyl) ligands to feature aluminum and gallium bridgeheads. The molecular structures of these derivatives similarly display interesting coordination modes which, in some cases, contrast greatly to those of the parent boron ligands. In Chapter 2, synthetic approaches for the preparation of novel dianionic tris(pyrazolyl) ligands, obtained via the use of magnesium and zinc as linker atoms, are summarized. Interestingly, the otherwise neutral {[MeMTpᴹᵉ²][Li₂]} fragment is found to associate with an additional Lipzᴹᵉ² molecule, thereby affording a series of [MeMTpᴹᵉ²][Li3(pzᴹᵉ²)Ln] compounds in which each lithium is coordinated to two pyrazolyl nitrogen atoms. Both chloride and iodide anions can also serve as capping ligands for the {[MeMTpᴹᵉ²][Li₃]}+ moieties, suggesting that the trilithio scaffold can be viewed as a trifold receptor for anions. Additionally, the tetrakis(pyrazolyl) derivatives, [(THF)2Li{μ-[M(pzᴹᵉ²)₄]}Li(THF)₂], have also been prepared and structurally characterized. Chapter 3 details the preparation, characterization, and reactivity of symmetric homodinuclear magnesium and zinc complexes, [MeM(pzᴹᵉ²)₃MMe]–, in which the two metal centers are bridged by three exo-bidentate pyrazolyl ligands. The bridging of two identical metal centers by more than two pyrazolyl groups is a rare structural motif, and so [MeM(pzᴹᵉ²)₃MMe]– represent important contributions to not only the chemistry of magnesium and zinc, but also to that of the pyrazolyl ligand. The reactivity of [MeZn(pzᴹᵉ²2)₃ZnMe]– towards protic reagents and trimethyltin halides has been investigated, and has most notably afforded a rare example of an anionic terminal zinc fluoride complex, [FZn(pzᴹᵉ²)₃ZnF]–. Additionally, the homodinuclear zinc hydride complex, [HZn(pzᴹᵉ²)₃ZnH]–, has been obtained and structurally characterized, and represents the first example of an anionic terminal zinc hydride compound. The spectroscopic characterization of both [HZn(pzMe2)₃ZnH]– and its isotopologue, [DZn(pzᴹᵉ²)₃ZnD]–, are summarized, as are the results of preliminary reactivity studies with CO2 and CS2, which suggest that insertion of these heterocumulenes into the Zn–H bonds is facile and affords, inter alia, zinc formate and zinc dithioformate species, respectively. Chapter 4 summarizes the exocyclic N-methylation of Nitron(S), a 1,2,4-triazole thione derived from Nitron. The molecular structures of both Nitron(S) and of the methylated derivative, Nitron(S)Me, are reported, and a comparison of metrical data indicates that (i) the structures of these thiones differ significantly from the dominant tautomer of Nitron and (ii) the structures of these thiones compare favorably with the NHC tautomer of Nitron. Analyses of these compounds using natural bond orbital (NBO) and natural resonance theory (NRT) methods are in accord with the experimental structures.

Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Two new potentially biodegradable aminopolycarboxylic acid ligands, iminodiglutaric acid tetra sodium salt (IDG-4Na) and iminoglutaricsuccinic acid tetra sodium salt (IGS- 4Na), were synthesized in reasonably good yield and purity. The commercially unavailable precursor for the two ligands, ethyl p-aminoglutarate, was synthesised in high yield and purity, and together with the two ligands were fully characterized by means of melting point measurements and various spectrometric techniques CH-NMR, 13C-NMR, MS and IR). For the first time, an electrochemical study has been conducted on the complexes of these ligands with selected transition metal ions (Zn2+, Cu2+ and Cd2+). An electrochemical technique, cyclic voltammetry (CV), was utilized on the study of the complexing ability of the ligands to the selected metal ions. An electrochemical cell comprising three electrodes was employed: thin film mercury coated carbon microelectrode was used as the working electrode, a Platinum wire as the auxiliary electrode, and a Ag/AgCI as the reference electrode. CV has been used and proven to offer a convenient route towards the determination of metal-ligand complex stability constants in aqueous media". The values of the logarithms of the metal-ligand formation constants obtained by this technique, when compared with other widely used aminopolycarboxylic acids (APCAs), show better complexing ability of the ligands with the transition metal ions. When the two ligands are compared, IGS showed greater affinity towards the selected transition metal ions. This is due to the fact that, in aqueous media, as the side chain ligators decrease, the stabilization energy of the complex increases. The formation stability constants were determined by plotting the change in the reduction potential (ΔE) against solution pH. A process making use of a modification of lingane equation was used. / AFRIKAANSE OPSOMMING: Twee nuwe potensieel bio-afbreekbare amienpolikarboksielsuurligande, iminobiglutaarsuur -tetranatriumsout (IBG-4Na) en iminoglutaarsuksiensuurtetranatriumsout (IGS-4Na), was vervaardig met redelike goeie opbrengs en suiwerheid. Die kommersïeel onverkrygbare voorloper van die twee ligande, etiel-B-aminoglutaraat, was berei met hoë obrengs en suiwerheid, en was saam met die twee ligande ten volle geïdentifiseer deur middel van smeltpunt bepalings en verskeie spektrometriese tegnieke CH-KMR, 13C-KMR, MS en IR.). Vir die eerste keer is 'n elektrochemiese studie uitgevoer op die komplekse van hierdie ligande met selektiewe oorgangsmetaalione (Zn2+, Cu2+, en Cd2+). 'n Elektrochemiese tegniek, sikliese voltametrie (SV), is gebruik om die komplekseringsvermoë van die ligande ten opsigte van die geselekteeerdr metaalione te bestudeer. 'n Elektrochemiese sel wat bestaan uit drie elektrodes is gebruik: 'n Dunlaag kwikelektrode bedek met koolstof is gebruik as die werkselektrode, 'n platinumdraad as die bykomende elektrode en 'n Ag/AgCI elektrode as die verwysingselektrode. SV is voorheen gebruik en bewys as 'n gerieflike metode vir die bepaling van metaalligandkompleksstabiliteitskonstantes in waterige media'. Die waardes van die logaritmes van die metaalligandvormingskonstantes wat verkry word deur hierdie tegniek, soos vergelyk met ander algemeen gebruikte amienpolikarboksielsure (APKSe), vertoon beter komplekseringsvermoë met die ligande deur middel van die oorgangsmetaalione. Wanneer die twee ligande met mekaar vergelyk word, het IGS-4Na groter affiniteit gehad vir die oorgangsmetaalione. Dit is as gevolg van die feit dat die stabiliteitsenergie van die kompleks in waterige media verminder word soos wat die sykettings van die ligande toeneem. Die vormingstabilitietskonstantes was bepaal deur 'n varandering in reduksie potensiaal (ΔE) teenoor die pH van die oplossings te plot. Die grafieke is verkry deur 'n aanpassing van die Lingnane-vergelyking te gebruik.

Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This investigation comprises the synthesis and characterisation of new macrocyclic ligands with pendant arms appended to the nitrogen donor atoms of 1,5,9-triazacyclododecane (12aneN3) and their coordination to various transition metal ions. The five macrocyclic ligands, 1,5,9-tris[(2S)-2-hydroxypropyl]-1,5,9-triazacyclododecane (THPTACD), 1,5,9- tris(2-hydroxy-2-methylpropyl)-1,5,9-triazacyclododecane (THMPTACD), 1,5,9-tris[(2S)-2- hydroxy-2-phenylethyl]-1,5,9-triazacyclododecane (THPETACD), 1,5,9-tris[(2S)-2- hydroxybutyl]-1,5,9-triazacyclododecane (THBTACD) and 1,5,9-tris(2-mercaptopropyl)- 1,5,9-triazacyclododecane (TMPTACD) were prepared by addition of pendant arms that contain alcohol or thiol end groups to a preformed 12aneN3 macrocycle. The 12aneN3 was synthesised from simple starting materials using 1,3-propanediol and bis(3-aminopropyl)- amine. The macrocycles with oxygen donor atoms on the pendant arms were prepared from the corresponding epoxides whereas for the one that contained sulphur donor atoms, propylene sulphide was used. The reaction progress was followed by 13C and 1H NMR spectroscopy and the final macrocyclic ligands were further analysed by mass spectrometry and in some instances, elemental analysis was also performed. Protonation constants of the free ligands were determined using potentiometric titrations at 25 oC and the ionic strength was kept constant at 0.1000 mol dm-3 using NaNO3. The log K1 values were 11.47, 10.96 and 10.47 for THPTACD, THBTACD and THMPTACD, respectively, whereas the corresponding values of 5.81, 6.02 and 5.94 were obtained for log K2. THPTACD is the most basic mainly due to less steric hindrance whereas THMPTACD is the least basic owing to high steric hindrance to both solvation and formation of strong hydrogen bonds of the protonated species to solvent molecules during the solvation step in a Born Haber-type cycle of the complete process. Protonated THBTACD is the most basic of the three mono-protonated ligands, a result that may be explained in terms of better correlation between inductive and steric effects. The second protonation constant is mostly influenced by inductive effects unlike the first protonation constant which is mostly determined by steric effects. The third protonation constant could not be established because of lack of sensitivity of the glass electrode in very high acidic medium. The complex stability constants of Co(II), Zn(II), Cd(II) and Pb(II) cations were similarly determined using potentiometric titrations at 25 ¡ÆC in 0.1000 mol dm-3 NaNO3. Log K values with THPTACD are 15.45, 21.22, 14.03 and 16.11 for Co(II), Zn(II), Cd(II) and Pb(II), respectively. THBPTACD has corresponding values of 13.93, 20.02, 13.55 and 15.01, whereas for THMPTACD the values of 14.63, 18.08, 12.91 and 14.36 log units were obtained. The Zn(II) 1:1 complexes are the most stable and those of Cd(II) the least stable. A crystal structure determination of [Zn(THPTACD)]2+ shows that optimal interaction between the Zn(II) metal ion and the donor atoms with their short Zn(II)-N bond lengths occurs. The short Zn(II)-N distances indicate that the metal ion is situated very close to the macrocyclic hole. On the other hand, each half of the hydrogen-bonded dimeric molecular structure of [Cd2(THPTACD)2]4+ has long Cd(II)-N bond lengths. Although metal nitrates, perchlorates and acetates were used in attempted crystal structure determinations, only metal nitrates formed suitable crystals. THPTACD complexes with Co(II), Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II) were subjected to such determinations. Each central metal ion in these complexes is six coordinate to the three N atoms of the parent macrocyclic ring on one plane and the three O atoms of the pendant hydroxypropyl arms forming another plane on the other face of the metal ion. The geometry of all six molecular structures is pseudo octahedral with the Cu(II) complexes being the most twisted towards a trigonal prismatic arrangement. The change towards trigonal prismatic can be attributed to packing forces overriding octahedral crystal field stabilisation effects. The overall chirality of the isomorphic complexes of Zn(II), Co(II), Mn(II), Ni(II) and Cu(II) with THPTACD is [¥Ë((2¥ë.)¥ä.¥ä)] whereas the overall chirality of each half of the dimeric [Cd2(THPTACD)2]4+ complex is [¥Ë(¥ë.(2¥ä.)¥ä)]. The Cu(II) complex with THPETACD has the same overall chirality as the Cu(II) complex with THPTACD but is less twisted towards trigonal prismatic geometry. Both Cu(II) complexes exhibited strong evidence of Jahn-Teller tetragonal distortion in the solid state with tetragonality parameter values of 0.87 and 0.81, respectively. The structure of a new di-¥ì-chloro bridged binuclear complex of Cd(II)-12aneN3 was also determined. The molecule contains an inversion centre coinciding with the crystallographic centre of symmetry. Finally, the molecular structure of the protonated 1,5-bis[(2S)-2- hydroxybutyl]-1,5,9-triazacyclododecane shows that the oxygen donor atoms of the two pendant arms are pre-organised for meridional coordination. The hydrogen bond network in this structure emphasises the important role that such weak interactions play in stabilising the proton even in solution during determination of protonation constants in triazamacrocycles with pendant arms carrying oxygen donor atoms.

To Hing-lun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Abstracts in English and Chinese. / ABSTRACT --- p.i / 摘要 --- p.ii / ACKNOWLEDGMENT --- p.iii / CONTENTS --- p.iv / ABBREVIATIONS --- p.vi / Chapter CHAPTER 1 --- Synthesis and Reactivity Studies of Copper Complexes Supported by a Pyridine-Containing Ligand / Chapter 1.A. --- General Introduction / Chapter 1.A.I. --- Introduction --- p.1 / Chapter 1.A.II. --- Dioxygen Activation by Copper-Containing Species --- p.2 / Chapter 1 A.III. --- Reactivity of Copper(I) Complexes Towards Dioxygen Binding --- p.11 / Chapter 1.A.IV. --- Synthetic Models for Copper-Containing Proteins --- p.12 / Chapter 1.A.V. --- Objective of This Work --- p.27 / Results and Discussion / Chapter 1.B. --- Synthesis and Characterization / Chapter 1.B.I. --- Synthesis / Chapter 1.B.I.a. --- Ligand Synthesis --- p.28 / Chapter 1.B.I.b. --- Synthesis of Copper(I) Complexes --- p.31 / Chapter 1.B.II. --- Characterization / Chapter 1.B.II.a. --- Physical Characterization of Complex25 --- p.33 / Chapter 1.B.II.b. --- Structural Studies / Chapter 1.B.II.b.i. --- Molecular Structure of Complex25 --- p.34 / Chapter 1.B.II.b.ii. --- Comparisons of The Structural Parameters of 25 with Those of 24 and Other [Cu1(u-Br)]2 Complexes --- p.37 / Chapter 1.B.II.c. --- Electrochemical Studies --- p.38 / Chapter 1.C. --- Reactivity Studies --- p.40 / Chapter 1.D. --- Summary --- p.44 / Chapter 1.E. --- Experimental Procedures --- p.45 / Chapter 1.F. --- References --- p.54 / Chapter CHAPTER 2 --- Synthesis and Reactivity Studies of Nickel Complexes With a N3O-Donor Ligand / Chapter 2.A. --- General Introduction / Chapter 2.A.I. --- Introduction --- p.61 / Chapter 2.A.II. --- Studies of Metal-Phenoxyl Radical Arrays --- p.67 / Chapter 2.A.III. --- Objective of This Work --- p.72 / Results and Discussion / Chapter 2.B. --- Synthesis and Characterization / Chapter 2.B.I. --- Synthesis of Nickel(II) Complexes --- p.73 / Chapter 2.B.II. --- Characterization / Chapter 2.B.II.a. --- Physical Characterization of Complexes 34 and 35 --- p.75 / Chapter 2.B.II.b. --- Structural Studies / Chapter 2.B.II.b.i. --- Molecular Structure of Complex 34 --- p.75 / Chapter 2.B.II.b.ii. --- Molecular Structure of Complex 35 --- p.78 / Chapter 2.B.II.b.iii. --- Structural Comparisons --- p.81 / Chapter 2.B.II.c. --- Electrochemical Studies --- p.82 / Chapter 2.C. --- Reactivity Studies --- p.84 / Chapter 2.D. --- Summary --- p.90 / Chapter 2.E. --- Experimental Procedures --- p.91 / Chapter 2.F. --- References --- p.94 / APPENDIX A General Procedure and Physical Measurements / Chapter A.I. --- General Procedures --- p.99 / Chapter A.II. --- Physical Measurements --- p.100 / APPENDIX B Crystallographic Data / Chapter B.I. --- Selected Crystallographic Data for Compounds 25，34 and 35 --- p.102

by Chan Sau Han. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references. / Abstracts in English and Chinese. / ABSTRACT --- p.i / 摘要 --- p.ii / ACKNOWLEDGMENT --- p.iii / CONTENTS --- p.iv / ABBREVIATIONS --- p.vi / Chapter CHAPTER 1 --- General Introduction / Chapter 1-A. --- Role of Copper in Biology --- p.1 / Chapter 1-B. --- A Brief Review on Radical Copper Proteins --- p.4 / Chapter 1-C. --- Objectives of This Work --- p.12 / Chapter 1-D. --- References --- p.13 / Chapter CHAPTER 2 --- Copper(II) and Zinc(II) Complexes containing N3O Tetradentate Ligands / Chapter 2-A. --- Introduction Results and Discussion --- p.14 / Chapter 2-B. --- Preparation of Tetradentate Ligands and Complexes --- p.27 / Chapter 2-C. --- Characterization --- p.36 / Chapter 2-D. --- Generation of Metal Phenoxyl Radical Species --- p.51 / Chapter 2-E. --- Summary --- p.57 / Chapter 2-F. --- References --- p.59 / Chapter CHAPTER 3 --- Copper(I) Complexes with N30 Tetradentate Ligands / Chapter 3-A. --- Introduction Results and Discussion --- p.62 / Chapter 3-B. --- Preparation of Copper(I) Complexes with N30 Tetradentate Ligands --- p.75 / Chapter 3-C. --- Characterization --- p.79 / Chapter 3-D. --- Reactivities of 86，87 and 88 toward Dioxygen --- p.88 / Chapter 3-E. --- Summary --- p.93 / Chapter 3-F. --- References --- p.94 / Chapter CHAPTER 4 --- Experimental Sections / Chapter 4-A. --- General Preparations and Physical Measurements --- p.97 / Chapter 4-B. --- Compounds Described in Chapter2 --- p.99 / Chapter 4-C. --- Compounds Described in Chapter3 --- p.113 / Chapter 4-D. --- Oxo-Transfer to Triphenylphosphine as Described in Chapter3 --- p.117 / Chapter 4-E. --- References --- p.119 / Chapter APPENDIX A --- 1H and13 C̐ưث1H ̐ưحNMR Spectra / Chapter A-1. --- Compounds Described in Chapter2 --- p.120 / Chapter A-2. --- Compounds Described in Chapter3 --- p.127 / Chapter APPENDIX B --- Crystallographic Data / Chapter B-1. --- X-ray Crystal Structure Data for Complexes in Chapter2 --- p.131 / Chapter B-2. --- X-ray Crystal Structure Data for Complexes in Chapter3 --- p.133 / Chapter APPENDIX C --- GC-MS Spectra / Chapter C-1. --- GC-MS Spectra for Standard Samples --- p.134 / Chapter C-2. --- GC-MS Spectra for the Reactions with Triphenylphosphine Described in Chapter3 --- p.136

by Yee-Lok Wong. / 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.