Joseph Schmit

Date of Award

1-4-1993

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

Duane E. Bartak

Abstract

This study centered on two specific goals. The first goal of this research was to conduct a detailed investigation of the electrochemical reduction of 6-bromo-1-heptene (1) including the fate of the reduction intermediate, the 1-methyl-5-hexenyl fragment. In the process, the use of this intermediate as a radical probe was validated. The second goal of this research was to conduct a comprehensive electrochemical investigation of the reductive mechanisms of the three alkyl naphthyl ethers, 1-methoxynaphthalene (2), 2-methoxynaphthalene (3), and 6-(1$\sp\prime$-naphthoxy)hept-1-ene (4).6-Bromo-1-heptene was reduced on platinum, mercury, and vitreous carbon electrodes to yield the bromide ion and a heptenyl radical also known as a 1-methyl-5-hexenyl radical. Although this radical could be further reduced at the electrode surface to yield a heptenyl anion, the rate of reduction was slow enough that cyclization of the 1-methyl-5-hexenyl radical competed with the reduction. Using product analysis and the Butler-Volmer model for heterogeneous electron transfer kinetics, the upper limiting rates for the reduction of the secondary radical to the corresponding anion on the various electrodes were proposed. Product analysis demonstrated that the 1-methyl-5-hexenyl fragment could be used as a radical probe in DMF solutions.1-Methoxynaphthalene, 2-methoxynaphthalene, and 6-(1$\sp\prime$-naphthoxy)hept-1-ene were reduced on platinum at potentials of $-$2.62$\sp1,$ $-$2.54, and $-$2.63 V vs SCE, respectively, to yield the corresponding radical anions. While the radical anions of all three ethers were found to undergo unimolecular fragmentation at the alkyl carbon-oxygen bond, the radical anion of 3 was found to be much more stable relative to the others. The radical anions of 2 and 4 were found to decompose with a rate constant of between 0.2 and 0.6 s$\sp{-1}.$ Through the use of the 1-methyl-5-hexenyl fragment, the radical anion of 4 was found to decompose forming an alkyl radical and the naphthoxide ion.

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