Title

Molecular capsule and redox effects of encapsulated guests

Date of Award

2004

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Chemistry

First Committee Member

Angel E. Kaifer, Committee Chair

Abstract

In this dissertation, the author describes the synthesis, characterization and self-assembly of ferrocenyl tetraurea calix[4]arene, binding study of viologens with cucurbit[7]uril (CB7) host and supramolecular self-assembly of viologen containing dendrimer. These studies were carried out using 1H NMR spectroscopy, UV-visible spectroscopy, IR spectroscopy and cyclic voltammetry techniques.Chapter one describes the synthesis and dimerization of new electrochemically active molecules based on calix[4]arene. The dimeric capsules are stabilized by the formation of multiple hydrogen bonds between the urea functional groups on the calix[4]arene upper rims. The attachment of ferrocene groups to calix[4]arene subunits should introduce electrochemical activity. By controlling the redox state of ferrocene, the thermodynamic stability of the dimerized calix[4]arene should be strongly perturbed. In other words, oxidation of ferrocene should lead to dissociation of the dimer due to electrostatic repulsion between adjacent ferrocenes.Chapter two investigates the formation of the non-covalent CB7·viologen inclusion complexes. We carried out a systematic investigation with a series of symmetric viologens having aliphatic substituents of variable length. Our data reveal that, although all the viologen guests are bound by CB7, the actual binding site strongly depends on the length of the alipathic substituents on the bipyridinium nucleus. These findings were exploited for the design and preparation of a new pseudorotaxane.Chapter three describes a method for the supramolecular self-assembly of viologen containing dendrimers. In this study, cyclic voltammetry and UV-visible spectroscopy were used to demonstrate that the presence of CB8 leads to a novel electrochemically and chemically driven assembly of CB8-[bis-viologen dendrimer]2+ ternary inclusion complex.

Keywords

Chemistry, Biochemistry; Chemistry, Organic

Link to Full Text

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