University of Illinois Urbana-Champaign

Part I: Rapid Synthesis of Dendrimers by an Orthogonal Coupling Strategy. Part II: Design, Synthesis, and Characterization of Hydrogen-Bond Mediated Self-Assembling Dendrimers

Zeng, Fanwen

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Description

Title
Part I: Rapid Synthesis of Dendrimers by an Orthogonal Coupling Strategy. Part II: Design, Synthesis, and Characterization of Hydrogen-Bond Mediated Self-Assembling Dendrimers
Author(s)
Zeng, Fanwen
Issue Date
1997
Doctoral Committee Chair(s)
Zimmerman, Steven C.
Department of Study
Chemistry
Discipline
Chemistry
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • Chemistry, Organic
  • Chemistry, Polymer
Language
eng
Abstract
  • Part I. Layered dendrimers were rapidly synthesized using an orthogonal coupling strategy. Fourth generation dendron 71 was prepared in four steps by sequential use of two AB$\sb2$ building blocks 66 and 67 under Mitsunobu esterification and Sonogashira coupling conditions. Further accelerated growth was achieved by merging the orthogonal coupling strategy with Frechet's branched-monomer approach. Thus, sixth generation dendron 81, with molecular formula $\rm C\sb{1292}H\sb{1369}IO\sb{242}$ and a molecular weight of 20897 amu, was synthesized in just three steps from the corresponding AB$\sb4$ monomers 72 and 73. In comparison to the most efficient dendrimer synthesis available, the orthogonal coupling strategy halves the number of synthetic steps needed by obviating protection-deprotection and activation chemistry.
  • Part II. Discrete aggregates with a size in the nano-scale were formed by the hydrogen-bond mediated self-assembly of dendritic macromolecules. Several hydrogen bonding units were investigated, including anthyridine and diaminodihydropyridine moieties that are complementary (AAA-DDD), and self-complementary isophthalic acid, and 6-aminonicotinic acid subunits. Among them, dendritic tetraacids 189a-d were shown to self-assemble in a generation-dependent manner. The lower generation tetraacid 189a prefers to form a series of linear aggregates, while the higher generation tetraacids 189b-d tend to form a cyclic hexamer. The observation was supported by SEC dilution studies, VPO, and comparison with covalent models 208a-c.
Graduation Semester
1997
Type of Resource
text
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http://hdl.handle.net/2142/77259

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