PROTON-EXCHANGE IN THE LOWEST EXCITED SINGLET-STATE OF 2-NAPHTHOL-6,8-DISULFONATE - DEMONSTRATION OF THE ESTABLISHMENT OF PROTOTROPIC EQUILIBRIUM IN THE EXCITED-STATE

The pH dependences of the fluorescence spectra of 2-naphthol-6, 8-disulfonate were evaluated in terms of the kinetics of excited-state proton transfer. Deviations from ideal fluorometric titration behavior were compensated by a simple Brϕnsted kinetic activity factor which accounted for the primary kinetic salt effect. Criteria for the establishment of prototropic equilibrium in the lowest excited singlet state are stated and when applied to 2-naphthol-6, 8-disulfonate, it is found that equilibrium prevails over most of the inflection region in the fluorometric titration. © 1979, American Chemical Society. All rights reserved.