Degradation of electronic excitation energy in protolytic reactions of 1-naphthol

On-Contact Quenching of 1-Naphtholate by Geminate Protons

“…The quenching of the 1-naphtholate emission at neutral pH's following adiabatic proton dissociation was already observed by the Kuz'min group more than 20 years ago . Kuz'min et al.…”

“…Equation 21 is formally identical with a thermally activated barrier crossing process . As it is not clear what is the actual mechanism of the quenching reaction, , we have chosen a form of eq 21 which uses an empirical relation motivated by Kramers' theory where η is the solvent viscosity, and β and B are parameters to be determined by the best-fit procedure. The motivation for using η as a fitting parameter stems from the observation that the isotope effect on k q , k q (H 2 O)/ k q (D 2 O), appears to be independent of η and was found to be 1.32 ± 0.03 when k q was plotted against η, Figure b.…”

“…The reaction parameters point toward a reaction, which is mediated on-contact by the solvent, although it is not yet understood by what mechanism. In this respect, the identification of an efficient proton self-quenching reaction following the photodissociation of 1-naphthol has not solved the general problem of elucidating the various quenching mechanisms of 1-naphthol and the 1-naphtholate anion. , Additional kinetic data on the quenching reaction of 1-naphthol and its derivatives is clearly needed before this question may be resolved. Such additional kinetic data may be easily obtained by the procedure outlined in this study.…”

“…Ion pair dynamics are a classic issue in chemical reactivity. − A related problem is the dynamic branching between self-neutralization and self-quenching , of electronically excited dyes following proton dissociation. Such photoacids undergo rapid proton dissociation in their electronic excited state, thus providing an efficient mean for creating ion pairs. − The excited-state photophysics of 1-naphthol, a model photoacid, have been extensively studied in solution over the past 50 years − following the early observations of photoacidity made by Förster and by Weller…”

“…Such photoacids undergo rapid proton dissociation in their electronic excited state, thus providing an efficient mean for creating ion pairs. [6][7][8][9][10] The excitedstate photophysics of 1-naphthol, a model photoacid, have been extensively studied in solution over the past 50 years [11][12][13][14][15][16][17][18][19] following the early observations of photoacidity made by Fo ¨rster 20 and by Weller. 21 Pines and Fleming were first to observe the self-quenching reaction of the 1-naphtholate anion by its geminate proton following its excited-state proton dissociation.…”