Hexiang Zhang

Graduation Semester and Year

2007

Language

English

Document Type

Thesis

Degree Name

Master of Science in Chemistry

Department

Chemistry and Biochemistry

First Advisor

Dmitry Rudkevich

Abstract

This dissertation describes approaches towards designs, syntheses, characterizations, and applications of supramolecular chemistry on carbon dioxide. Chapter 1 briefly overviews the field of supramolecular chemistry and highlights its horizons, also introduces the progress of sensing devices on chemical warfare agents. Chapter 2 introduces a modular approach to detect chemical warfare agent: phosgene by Fluorescence Resonance Energy Transfer (FRET). It combines the chemical reactivity between amines and phosgene with fluorescence properties of coumarin fluorophores, forms a fast, selective and reliable sensing system. Chapter 3 overviews the chemistry between amines and carbon dioxide and introduces the applications of this reaction in molecular recognition, organic gelations and cation separations. A novel strategy for alkali metal cation separations is demonstrated by introducing dibenzo-18-crown-6 and lysine derivatives, which successfully extract metal ions from aqueous solution. CO2 was used to build reversible, supramolecular polymeric materials. Formation of cross-linked, porous supramolecular polymers leads to instant entrapment of organic guest species. These can be stored and then released upon changing solvent polarity, temperature, pH, and concentration. Chapter 4 presents a calix[4]arene based novel strategy for sodium cation separation. Because of high affinity towards sodium cations, calix[4]arene tetraester is selected and functionlized by ethylenediamine on the lower rims. After entrapment of sodium cations, CO2 gas constructs these calix[4]arene sodium complexes into cross-linked supramolecular polymers. These polymers employ dynamic, thermally reversible carbamate bonds. This approach shows high efficiency and accuracy.

Disciplines

Chemistry | Physical Sciences and Mathematics

Comments

Degree granted by The University of Texas at Arlington

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