Ultrafast excited-state proton transfer in 1-naphthol

The first direct observation of the excited-state proton-transfer reaction of 1-naphthol in aqueous solution is reported.Using picosecond, time-resolved emission spectroscopy; the lifetime of 1-naphthol at pH = 7 is found to be 33 ± 5 psec, one to three orders of magnitude faster than previous determinations.Coupled with steady-state techniques, direct, time-resolved measurements provide a generally applicable method for the accurate determination of the numerous rate constants required for a complete description of the kinetics of electronically excited 1-naphthol in water.Comparison of the present results on 1-naphthol with previous work on 2-naphthol reveals striking differences•in the excited-state reaction dynamics of these seemingly similar molecules.