Doctoral Dissertations

Date of Award

12-1985

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Chemistry

Major Professor

T. Ffrancon Williams

Committee Members

John E. B., C. Woods, W. E. B.

Abstract

The radical cations of several classes of oxygen-containing organic compounds have been generated by y-irradiation of dilute solutions in solid perhalocarbon (freon) matrices, and detected and characterized by the Electron Spin Resonance technique, including those of ether, acetal, aldehyde, ketone and epoxide compounds.

Acetal radical cations are found to be oxygen-centered radical species, and show very large hyperfine interactions (up to 160 G) to the hydrogens on the methylene bridge linking the two oxygens, in accord with the Whiffen effect. Replacenent of one methylene hydrogen with an alkyl group results in rearrangement to give the corresponding neutral alkyl radical at 77 K.

Aldehyde and ketone radical cations are found to be oxygen-centered σ radicals, aldehyde cations exibiting large coupling to the aldehydic hydrogen. Long-range hyperfine interactions to σ -hydrogens has been unequivocally proven to require a co-planar (W-plan) arrangement by isotopic substitution of an equatorial σ -hydrogen in 2-adamantanone.

Epoxide compounds are found to give a C...C ring-opened 2A2 planar radical cation in several freon matrices (CCFCl3 , CF3CCl3, and OCl4). The C...C ring-opened planar structure of the oxirane radical cation has been conclusively proven by an ESR study of the doubly-labeled 13C oxirane radical cation. Localized forms of the C...C ring-opened cations of oxirane and oxirane derivatives are detected in the CFCl2CF2Cl matrix.

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