Novel photochemical reactions of bicyclo[2.2.2]octa-2,5-diene radical cations

Abstract

The radical cation of bicyclo[2.2.2]octa-2,5-diene produced in a γ-irradiated Freon matrix at 77 K shows a broad charge-resonance absorption band with λ max =680 nm. In contrast to earlier experiments in argon matrices, it was found that the primary photoreaction of this species is a cleavage to yield the recently described complex cation between benzene and ethylene whose λ max happens to coincide with that of the above precursor cation. This complex cation can in turn be converted eventually to 1,3,5,7-octatetraene radical cation