published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

by Mok-Yin Chow. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1992. / Includes bibliographical references (leaves 55-58). / Acknowledgement --- p.1 / Abstract --- p.2 / Contents --- p.3 / List of Figures --- p.4 / List of Tables --- p.5 / Chapter 1. --- Introduction --- p.6 / Chapter I. --- Chemistry of pseudohalides --- p.6 / Chapter II. --- Infrared spectroscopy of pseudohalides --- p.8 / Chapter III. --- Chemistry of metal carboxylates --- p.10 / Chapter IV. --- Infrared spectroscopy of carboxylates --- p.13 / Chapter V. --- Chemistry of betaine ligands --- p.14 / Chapter VI. --- Objectives of this research --- p.15 / Chapter 2. --- Experimental --- p.17 / Chapter I. --- Preparation --- p.17 / Chapter II. --- X-ray crystallography --- p.21 / Chapter 3. --- Results and discussion --- p.23 / Chapter I. --- "Isostructural complexes Co2(bet)2(N3)4 1,Zn2(bet)2(N3)42, Cd2(bet)2(N3)4 3, and Cd2(bet)2(NCO)4 4" --- p.23 / Chapter II. --- Copper(II) complex Cu2(bet)2(N3)2(N03)2 5 --- p.29 / Chapter III. --- Cadmium(II) complexes Cd3(bet)4(SCN)6(H20)2 6 and Cd(prbet)(NCS)2 7 --- p.34 / Chapter IV. --- Barium(II) complex Ba(pybet)2(NCS)2 8 --- p.43 / Chapter V. --- Cobalt(II) complex [Co(pybet)2(NCS)(H20)3]2[Co(NCS)4] 9 --- p.49 / Chapter VI. --- Conclusion --- p.53 / References --- p.55 / Publications based on work reported in this thesis --- p.59 / Appendix --- p.60

Wu, Nip Po. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also Chinese.

by Shan-Ming Kuang. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 135-152). / 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.

In Chapter 1, I discuss the synthesis and characterization of lithium tris(pyrazolyl)hydroborato complexes, [TpR1,R2]Li. Group 1 [TpR1,R2]M complexes serve as key starting points to access many other main group and transition metal complexes; however, the synthesis and crystal structures of [Tp R1,R2]Li has not been reported. Molecular structures of [TpBut]Li and [TpBut,Me]Li show these complexes are trigonal pyramidal, an unusual geometry for lithium. These complexes are also able to bind small molecules to form four-coordinate pseudo-tetrahedral complexes, [Tp]Li-L (L = MeCN, pzButH, and H2O). The binding constants for the association of acetonitrile to [TpBut]Li and [TpBut,Me]Li are 0.84M-1 and 0.96M-1, respectively, indicating that the dissociation of MeCN is facile in solution. In addition, [TpBut,Me]Li serves as transmetallating agent to yield the cadmium halide complexes, [TpBut,Me]CdX (X = Cl, Br, I). In Chapter 2, I discuss the synthesis and characterization of organometallic cadmium complexes supported by the nitrogen-rich multidentate ligands, tris(pyridylthio)methane, [Tptm]H; tris(1-methyl-imidazolylthio)methane, [TitmMe]H; and tris(1-methyl-benzimidazolylthio)methane, [TitmiPrBenz]H. These ligands are in the nascent stages of development and there are only a few metal [Tptm] and [TitmMe] complexes in the literature. An investigation of the reactivity of [L]CdN(SiMe3)2, [L]CdOSiMe3, and [L]CdOSiPh3 ([L] = [Tptm], [TitmMe], [TitmiPrBenz]) shows these complexes provide access to a variety of organometallic cadmium complexes, [L]CdX, (X = OAc, Cl, Br, O2CH, NCO). The characterization of cadmium acetate and formate complexes is significant due to their structural similarity with the metal bicarbonate intermediate formed by zinc and cadmium-substituted carbonic anhydrase. In addition, the synthesis and characterization of cadmium methyl complexes, [L]CdMe, is discussed. The application of heat to a mixture of [TitmiPrBenz]H and CdMe2 results in isomerization of the ligand to [S3-TitmiPrBenz]CdMe. This sulfur-rich [S3-TitmiPrBenz] ligand is not reported in the literature and is ripe for further investigation. The solid state structures of these compounds provide a comparison with biologically relevant [Tp] or [Tm] cadmium methyl complexes in the literature. In Chapter 3, I describe the synthesis and structural characterization of [BmButBenz]M (M = Na, K) and [BmRBenz]Ca(THF)2 (R = Me, But) are discussed. The sulfur-rich tripodal ligand tris(imidazolylthio)hydroborato, [Tm], was previously designed to serve as a softer version of the [Tp] ligand. Metal [Tm] complexes are prevalent in the literature and have often been used as molecular mimics of sulfur-rich enzyme active sites. Recently, the benzannulated [TmRBenz]M complexes were reported and were found to promote k3 coordination toward the metal center. To allow for an in-depth investigation of the newly synthesized [BmRBenz] class of ligand, the [BmButBenz]M (M = Na, K, Ca) complexes were synthesized and compared to previously reported metal [BmMeBenz]M complexes. Additionally, the [BmMeBenz]2Ca(THF)2 was synthesized and characterized via X-ray diffraction. The molecular structure of [BmMeBenz]2Ca(THF)2 shows the complex is monometallic with an uncommon eight-coordinate dodecahedral calcium center. [BmMeBenz]2Ca(THF)2 is the first molecular structure of calcium coordinated to the [Tm] or [Bm] ligand class. In Chapter 4, I discuss the synthesis and characterization of mercury alkyl complexes supported by the [TmMe], [BmR], [TmRBenz] and [BmRBenz] ligands (R = Me or But). As previously mentioned, [Tm]M complexes are considered biologically relevant molecular models of enzyme active sites. With this in mind, [TmBut]HgR (R = Me,Et) complexes have served as mimics for the mercury detoxification enzyme MerB. A previous study by our group showed that the adoption of multiple coordination modes of the ligand in [TmBut]HgR plays a significant role in the activation of the Hg-C bond toward protonolysis. The molecular structures of the [TmR], [BmR], [TmRBenz], and [BmRBenz] mercury alkyl complexes show that they adopt various coordination modes, ranging from k1 to k3. Preliminary competition experiments in which benzenethiol was added to [TmR]HgEt and [TmRBenz]HgEt indicate that the Hg-C bond in [TmMeBenz]HgEt was cleaved faster than that in [TmMe]HgEt. Conversely, the Hg-C bond in [TmBut]HgEt was cleaved faster than that in [TmButBenz]HgEt, indicating that benzannulation and the size of the R-group on the [Tm] ligand play important roles in Hg-C bond cleavage.

Chapter 1 gives a brief introduction to metal complexes supported by anionic nitrogen-based ligands. / Chapter 2 describes the synthesis, structural characterization and reactivity of Mn(II), Fe(II) and Co(II) amides derived from the strongly electron-withdrawing [N(C6F5)(C6H3Pr i2-2,6)]- ligand (L 1). Twelve new compounds, including the ligand precursor HL 1, and three alkali-metal and eight late transition metal derivatives of L1, were prepared. Reactions of MCl2 (M = Mn, Fe, Co) with [Li(L1)(TMEDA)] (2) yielded the monoamido complexes [M(L1)Cl(TMEDA)] [M = Mn (5), Fe ( 6), Co (7)]. Treatment of [Li(L1)(THF) 3] with MCl2 (M = Fe, Co) afforded the diamido complexes [M(L1)2(mu-Cl)Li(THF)3] [M = Fe ( 8), Co(9)]. The reaction chemistry of the Co(II) complex 7 was investigated. Treatment of the Co(II) derivative 7 with LiMe, NaN3 and NaOMe gave the corresponding methyl-, azido- and methoxide-amide complexes, namely [Co(L1)(Me)(TMEDA)] ( 10), [Co(L1)(N3)(TMEDA)] (11) and [Co(L1)2(mu-OMe)Na(TMEDA)] (12), respectively. The solid-state structures of complexes 5--12 were determined by X-ray crystallography. / Chapter 3 reports on the synthesis and catalytic properties of lanthanide(III) complexes derived from the unsymmetrical [PhC(NSiMe3)(NC6 H3Pri2-2,6)] - ligand (L2). The lithium and potassium salts of L2, and eight lanthanide(III) derivatives of L2 were synthesized. A series of Ln(III) complexes of the general formula [Ln(L 2)2(mu-Cl)2Li(TMEDA)] [Ln = Y (17), Eu (18), Er (19), Lu (20)] and [Li(THF) 4][Ln(L2)2Cl2] [Ln = Ce ( 21), Nd (22), Sm (23)] were synthesized by the reactions of anhydrous LnCl3 with two molar equivalents of [Li(L2)(TMEDA)] (15). In addition, the neutral dimeric yttrium(III) complex [Y(L2)2(mu-Cl)] 2 (24) was also prepared by the reaction of anhydrous YCl 3 with the potassium amidinate [K(L2)]n (16). The catalytic properties of complexes 20--22 towards the ring-opening polymerization of epsilon-caprolactone were also studied in this work. / Chapter 4 reports on the coordination chemistry of L2 towards divalent lanthanide metal ions. Three neutral divalent lanthanide complexes, [Ln(L2)2(THF)n] [Ln = Sm, n = 2 (25); Ln = Eu, n = 2, (26); Ln = Yb, n = 1 (27)], were prepared by treatment of LnI2(THF) 2 with the potassium amidinate [K(L2)]n . The reaction chemistry of 25--27 as one-electron transfer reagents has been examined. This led to the isolation of six lanthanide(III) complexes (28--33). Treatment of 25--27 with PhEEPh (E = Se, Te) gave the corresponding Ln(III) chalcogenolate complexes [Ln(L2)2(mu-EPh)]2 [Ln = Sm, E = Se (28); Ln = Eu, E = Se (29); Ln = Sm, E = Te ( 31)] and [Yb(L2)2(SePh)(THF)] (30). Besides, the reaction of 27 with iodine resulted in the isolation of the iodide complex [Yb(L2)2(I)(THF)] ( 32), whilst treatment of 25 with dicyclohexylcarbodiimide led to [Sm(L2)2{CyNC(H)NCy}] (33). / Chapter 5 summarizes the results of this research work. A brief suggestion on future directions of this research project is also discussed. / The present research work was focused on the coordination chemistry of the highly electron-withdrawing [N(C6F5)(C6H 3Pri2-2,6)]- ligand and the unsymmetrical [PhC(NSiMe3)(NC6H 3Pri2-2,6)- ligand. The first part of this work was centered on the synthesis, structure and reactivity of late transition metal complexes supported by the [N(C6F5)(C6H3Pr i2-2,6)]- ligand (L 1). The second part of this work dealed with the chemistry of trivalent and divalent lanthanide complexes derived from the bulky [PhC(NSiMe3 )(NC6H3Pri 2-2,6)]- ligand (L2). / Yao, Shuang. / Adviser: Hung Kay Lee. / Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0317. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.

"January 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / 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.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Chemistry / Master / Master of Philosophy