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) irradia ted by ionizing radiation at 77 K in the presence of SF6 and cyclopropane ( cC(3)H(6)). In addition to the 1,2-dimethylcyclohexyl radical, the 1,2-dime thylcyclohexene 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-DMCW (+))in the 1,2-DMCH matrix. The reaction shows a c is-trans stereo-selectivity and proceeded only for the cis-isomer. Furtherm ore, the I,2-DMCH + generated in the halocarbon matrix was found to be conv erted into the 1,2-DMCHe (+) by photo-illumination at lambda greater than o r equal to 350 nm. (C) 1999 Elsevier Science Ltd. All sights reserved.