Hydrogen molecule detachment in irradiated 1,2-dimethyl cyclohexane: stereo-selective reaction

An EPR study was carried out for 1,2-dimethylcyclohexane (1,2-DMCH) irradiated by ionizing radiation at 77 K in the presence of SF6 and cyclopropane (cC3H6). In addition to the 1,2-dimethylcyclohexyl radical, the 1,2-dimethylcyclohexene cation radical was observed which was formed by a selective hydrogen detachment at the C1 and C2 positions of 1,2-dimethylcyclohexane cation radical (1,2-DMCH+) in the 1,2-DMCH matrix. The reaction shows a cis-trans stereo-selectivity and proceeded only for the cis-isomer. Furthermore, the 1,2-DMCH+ generated in the halocarbon matrix was found to be converted into the 1,2-DMCHe+ by photo-illumination at λ≥350 nm