Photochemical reactions of quinonoid compounds with phosphorus derivatives

The photoreactions of tetraethylpyrophosphite, tetraphenylbiphosphine, diphenylphosphine oxide, and tetraethylbiphosphine disulphide with five quinones or quinonoid compounds have been studied by esr spectroscopy. .P(O)Ph2, .P(O)(OEt)2 radicals add to both carbon-carbon and carbon-oxygen double bonds, while with Ph2P. and .P(S)Et2 radicals only the species resulting from addition to a carbonyl group are observed. It is also reported that the photogenerated quinone triplets react with tetraethylpyrophosphite leading to the formation of diethoxyphosphonyl radicals, which in turn add to other ground state quinone molecules, the diethoxyphosphinyl adduct to a carbonyl group being also formed in the porocess.