EPR study of cation-radicals of cyclic alkenes in chlorofluorocarbon matrices

By gamma irradiation of cycloheptatriene, bicyclo(3.3.0)octene and dehydrodicyclopentadiene in chlorofluorocarbon matrices at 77 K the radical cations generated by electron loss from the parent molecules have been obtained and their electronic structure analyzed by EPR spectroscopy and by INDO and MNDO-PM3 molecular orbital calculations. On warming above 77 K these species undergo deprotonation to form neutral radicals. In the case of dicyclopentadiene the primary radical-cation is not stable at 77 K but decomposes probably by ring opening giving a bis-allylilic type cation-radical. (author)