Author

Zhuang

Date of Award

4-2002

Degree Name

Master of Science

Department

Chemistry

First Advisor

Dr. Subra Muralidharan

Second Advisor

Dr. Marc W. Perkovic

Third Advisor

Dr. Elke Schoffers

Access Setting

Masters Thesis-Open Access

Abstract

Chiral dendrimers with .unique ordered structures are especially attractive for the recognition of chiral molecules based on the three point contact model. We have successfully synthesized first generation chiral dendrimers containing L- and D- tryptophan methyl ester moieties and characterized them by NMR, IR, UV-Visible, MS, and optical activity. L-tryptophan methyl ester dendrimer was converted to its acid form in order to attach it to aminopropyl silica for the HPLC separation of enantiomers. The aminopropyl silica containing 1.52mmols/g of NH2 groups binds about 0.3mmols of dendrimer per gram and has about 0.4mmols of free NH2 groups per gram. Significant differences were observed in the retention times of the enantiomers of propranolol, 1-phenyl-1-propanol, 2-phenyl-1-propanol under a variety of mobile phase compositions. Mixtures of enantiomers could not be separated with the current column due to nonspecific interactions with free NH2 groups which resulted in poor efficiencies. However the stereoisomers 1-phenyl-1-propanol and 2- phenyl-1-propanol could be separated with much higher selectivities than with an ODS column. The present study has provided valuable fundamental information on the chiral recognition efficacy and mechanism of L-tryptophan dendrimer.

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