Kinetics of heat-induced and photochemical transformations of quinonimines and their derivatives

Heat-induced transformations of N-2,6-diisopropylphenyl]-3,5-di(tert-butyl)-, N-2,6-diethylphenyl]-3,5-di(tert-butyl)-, and N-2-methyl-6-ethylphenyl]-3,5-di(tert-butyl)-o-benzoquinonimines in nonane follow the first-order rate equation, whereas that of N-2,5-di(tert-butyl)phenyl]-3,5-di(tert-butyl-o-benzoquinonimine obey the second-order rate equation. Kinetic parameters of these reactions have been determined. 4aH-Phenoxazine derivatives of quinonimines are intermediates of the heat-induced transformations following the first-order kinetics; under the irradiation with 405 nm light they undergo the ring opening to give the starting compounds with quantum yield close to unity.