Electron spin resonance study of radicals in γ-irradiated mono- and poly-cyclic olefins: substituted cyclopentadienes

Abstract

The matrix isolation technique coupled with e.s.r. spectroscopy has been used to obtain information regarding the nature and the reactions of free radical intermediates from the radiolysis of some substituted cyclopentadienes. The mechanisms of radiolysis are mainly concerned with changes in the cyclopentadienyl part of the molecules and predominantly involve the breakage of the weakest bisallylic C–H bonds and [1,4] opening of the conjugated system. An ionic mechnism has been attributed to the latter process by comparisons with u.v. irradiation experiments. Interesting e.s.r. properties of new cyclopentadienyl-type radicals have also been observed.