Abstract: Different bis(p-N,N-dimethylamino)benzylidene ketones DMBK(DMBA、DMBPand DMBH)were used as a new kind of photoinduced electron transfer photocoloration system by combination with diphenyliodonium salt.The DMBK/DPIOF combination system exhibites a good thermal stability in dark and rapidly undergoes electron transfer from excited DMBK to DPIOF under irradiation with photofading of DMBK dye. The photofading rate for different DMBK was determined in the order:DMBA>DMBP>DMBH.The electron transfer induced photocoloration with maximum absorption peak at 700 nm was observed only in the case of DMBK and optical density increaJses with incresaing irradiation time.But it could not be observed in the DMBP and DMBH probably due to the formation of non-coplane intermediates.Thephotocoloration rate and maximum density of DMBA depend considerably on the concentration and nature of solvents.The photoreaction processes of electron transfer photofading at short wavelength range and photooloration at long wavelength range were preliminary discussed.

Key words: electron transfer, photocoloration, bis(p-N, N-dimethylamino)benzylidene, ketones/iodonium salt system