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Document Type

Thesis - University Access Only

Award Date

1998

Degree Name

Doctor of Philosophy (PhD)

Department / School

Chemistry and Biochemistry

Abstract

Studies were conducted to determine optimization for attachment of dendrimers to a solid support utilizing two series of differentiated dendrimers. Initially two dendrimers were synthesized via per-Michael additions of nitro methane to either methyl or t-butyl acrylate followed by a Raney Nickel reduction of the nitro moiety. Lactam formation favored by the methyl ester tris was prevented by forming a self-protecting amine salt through reducing in an acidic environment. The amine salt was subsequently converted to the free base. The methyl ester and the t-butyl ester amine dendrimers were acylated with a series of acid halides terminating with a halide functionality. Both series yielded dendrimers with alkyl chain lengths of 1, 3, 4 and 5 carbons. Bis-oxamide dendrimers and alkene dendrimers were synthesized with methyl ester and /-butyl termini. The two series of dendrimers were immobilized on both silica gel and 3- aminopropyl functionalized silica gel. Solid-state NMR techniques 13C CPMAS, 1H spin lattice relaxation including temperature studies and 1H transverse relaxation time were used to characterize the composite. Optimal resolution of the peaks in the 1H spectra was obtained by adding 20-30 μL of CDC13 to the sample. No significant difference existed in the correlation times of the adducts appended to silica gel at 22 °c due to the length of the alkyl chain or the size of the ester termini. Increased correlation times were experienced by both ester series appended to a functionalized silica gel compared to the corresponding series appended to silica gel, with the methyl ester series demonstrating the greatest increase. The difference in the correlation time for the methyl ester adduct with a chain length of one appended to silica gel verses functionalized silica gel was approximately equivalent to the difference seen for the molecule appended to silica gel at 22 °c versus 60 °c.

Library of Congress Subject Headings

Dendrimers
Silica gel
Amides

Format

application/pdf

Number of Pages

136

Publisher

South Dakota State University

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