Photoinduced electron transfer in the paraquat–thiourea molecular complex

摘要: The bipyridinium ion paraquat forms a 1 : association complex with thiourea in aqueous solution. Excitation the region 360–440 nm high-intensity pulse causes transient changes visible absorption spectrum which are completely reversible within 10 s. A study of time evolution indicates that primary photoproducts radical cation and cation. Subsequent dimerization radicals produces formamidine disulphide, which, along radicals, reacts to regenerate complex.