Water-assisted proton transfer in the monomer of 7-azaindole

Ultrafast pump-probe spectroscopic studies on the hydrated 7-azaindole mono mer are presented. The experiments provide evidence that excited-state prot on transfer in the gas-phase hydrated 7-azaindole monomer may be possible, as predicted by theory, and can occur by means of a water proton bridge. As explained in the text, full tautomerization may not be occurring, but rath er the transfer of a proton from the 7-azaindole monomer to the solvating w ater molecules. A calculated geometry fur the structure of 7-azaindole clus tered with four waters is presented and used to explain the rate increase o bserved in this species compared to the 7-azaindole monomer clustered with two and three waters.