Intramolecular hydrogen bonding in bisphenol developing agents for photothermographic application

The effects of intramolecular hydrogen bonding on the electron transfer properties of a series of bisphenol derivatives, as compared with those of monophenol derivatives in which a hydroxy group of the bisphenols is replaced with a methoxy group, have been investigated in relation to their utility as photothermographic developers. The oxidation of bisphenol derivatives with one-electron oxidants occurs to give the radical cation, followed by deprotonation, to produce the phenoxyl radical. Both the radical cations and phenoxyl radicals have been detected by laser flash photolysis measurements. Rates of hydrogen transfer reactions from a series of bisphenol derivatives to cumylperoxyl radicals have also been determined by monitoring the decay of the ESR signal of cumylperoxyl radical produced by photoirradiation of an oxygen saturated propionitrile solution of cumene and di-t-butylperoxide in the presence of the bisphenol derivatives. Intramolecular hydrogen bonding plays an important role in deter-mining the overall oxidation reactivity in the two-electron oxidation process of bisphenol derivatives by decreasing the one-electron oxidation potentials and also by facilitating the deprotonation step from the bisphenol radical cation to produce a phenoxyl radical.