Solvation of 7-azaindole in alcohols and water: Evidence for concerted, excited-state, double-proton transfer in alcohols

Article abstract of DOI:10.1021/ja00075a035

The proton inventory technique is used for the first time to investigate excited-state proton-transfer processes. The nonradiative pathways of the biological probe, 7-azaindole, in methanol, ethanol, and water are examined. Results in methanol and ethanol demonstrate the involvement of two protons in the transition state for the excited-state double-proton transfer process. These data provide the first experimental evidence suggesting a concerted tautomerization reaction of 7-azaindole in alcohols. The data for 7-azaindole in water are interpreted in terms of a nonradiative pathway that is qualitatively different from that in alcohols. We propose abstraction of the N₁ hydrogen by water as a possible nonradiative decay process.