Effect of silver ions on the photochemical properties of N-methyldiphenylamine

Silver(I) ions have been found to quench the fluorescence of N-methyldiphen ylamine (1) and reduce the quantum yield of cyclization reaction of 1 to N- methylcarbazole (3). Comparison of relative quenching rate constants for th e singlet- and triplet-excited states of 1 has enabled the evaluation of tw o components, physical and chemical, in silver(I) action on the triplet-exc ited 1 ((3)1), namely: acceleration of the intersystem crossing processes ( 3)1 --> 1 and inhibition of the reaction of (3)1 photocyclization to the tr iplet-excited N-methyldihydrocarbazole (2). (C) 2000 Published by Elsevier Science S.A. All rights reserved.