Solvent effects of photoinduced electron transfer reactions of triplet fluorenone with amines

The property of the lowest excited triplet state of fluorenone (FL) in acetonitrile, ethyl acetate, toluene, cyclohexane has been investigated using time-resolved laser flash photolysis. The appearances of the corresponding cation radicals and anion radicals suggest that the electron transfer reaction occurs between 3 FL* and amines. Experimental results show a decrease in the quenching rate constants along with reducing solvent polarity. The change of quenching rate constants of the FL excited triplet with the three N,N -dimethylaniline derivatives are explained using the Hammett constant.