ATTEMPTS AT DIRECT-DETECTION OF REACTIVE SPECIES IN SELECTIVE EXCITATION OF THE CONTACT CHARGE-TRANSFER PAIRS OF HEXAMETHYLBENZENE AND OXYGEN

Pulsed laser excitation of contact charge transfer pairs of hexamethyl benzene (HMB) and oxygen in methanol-acetonitrile gave no evidence for intermediacy of reactive species such as HMB radical cations and pent amethylbenzyl cations (ArCH2+), though stationary irradiation of the p air in hydroxylic solvents afforded distinct products arising from the cationic species. The mechanism of reactions was discussed in compari son with 9,10-dicyanoanthracene-sensitized oxygenation of HMB.