published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

by Leung Cham-fai. / "July, 2003." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (p. 135-150) and index. / 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.

Chapter 1 gives a brief introduction about dendrimers, their synthesis, characterization methods and applications. Chapter 2 summarizes the current research progress on the various dendritic nanostructures, namely, dendronized polymers, dendrimer-linear polymer hybrids, poly(dendrimer)s and poly(dendrimer) networks. In Chapter 3, we reported the detailed synthesis of the two series of dendritic macromonomers (S-Gn and L-Gn, n = 1--3) with different branch lengths (C-O for S-Gn and C--C--C--O for L-Gn) and hence varying structural flexibilities. The structures of these dendritic compounds were characterized by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), mass spectrometry (MS) and elemental analysis. The polymerization reactions with trans -Pt-linker 65 was firstly conducted to obtain organoplatinum poly(dendrimer)s Pt-S/L-Gn 144-149. It was found that the structurally more rigid dendritic mamcromonomers (S-Gn series) have a higher degree of polymerization (DP) than the structurally more flexible one (L-Gn series) of the same generation. This was attributed to the formation of cyclic oligomers in the latter series. In Chapter 4, we investigated the polymerization behavior of the two series of dendritic macromonomers towards two other Pt-linkers of different geometry, namely, cis-Pt-linker 152 and long-trans-Pt-linker 156 to obtain poly(dendrimer)s cis-Pt-S/L-Gn 157-162 and long-trans-Pt-S/L-Gn 163-168 respectively. It was revealed that only oligomers and/or cyclic oligomers were formed in both S-Gn and L-Gn series in the former case. In contrast, poly(dendrimer)s long-trans-Pt-S/L-Gn 163-168 were obtained in high DP values and the formation of oligomers and/or cyclic oligomers was greatly suppressed. A model was proposed to account for the different polymerization outcomes based on the different steric and structural environment of the two reacting partners. A conclusion of this work and an outlook of the project were given in Chapter 5. / This thesis described the research work on the synthesis of poly(dendrimer)s using an outer-sphere--outer-sphere connection strategy. Two G1--G3 series of dendritic macromonomers having short branches ( 73-75) and long branches (76-78) containing two surfaces (functionalized acetylene surface groups) were prepared in high purity and copolymerized with three different type of platinum linkers 65, 152 and 156 to form organoplatinum poly(dendrimer)s. The structural effects of the dendritic macromonomers and platinum tinkers on the polymerization efficiency were investigated. / Cheung, Siu Yin. / "December 2009." / Adviser: Hak-Fun Chow. / Source: Dissertation Abstracts International, Volume: 72-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 146-159). / 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. / Abstract also in Chinese.

abstract / Chemistry / Doctoral / Doctor of Philosophy