Photophysical behaviour of 4,4'-dihydroxydiphenyl sulphone

The effect of solvents on absorption and fluorescence of 4,4'-dihydroxydiphenyl sulphone (DHDPS) indicates that the net effect of two electron donating hydroxyl groups is very less on spectra of diphenyl sulphone (DPS). The small solvatochromic shifts also reveal that the change in dipole moment of DHDPS during excitation is negligible. Its behaviour in S-1 state is found to be different from diaminodiphenyl sulphones which possess twisted intramolecular charge transfer (TICT) character. Acidity constants for neutral-monoanion equilibria in S-0 and S-1 states have been determined and discussed.