Effect of temperature on photoinduced double proton transfer in the excited state of double hydrogen bonded dimmers of 7-azaindole

CHED 1396

Nahid Shabestary, nshabes@siue.edu, Amanda L. Hustedt, ahusted@siue.edu, and Danielle N. Reed, dareed@siue.edu. Department of Chemistry, Southern Illinois University Edwardsville, Box 1652, Edwardsville, IL 62026-1652
Photoinduced double proton transfer is a fast occurring reaction that synthesizes a tautomer in the excited state of double hydrogen bonded dimers. Concentrated solutions of 7- azaindole in non-hydrogen bonding solvents exhibit two fluorescence bands. The second band is suggested to have originated from the tautomer. In order to understand this phenomenon more fully the effects of temperature have been explored. The relative intensities of the normal violet fluorescence, F1, and the green tautomer fluorescence, F2, are examined with temperature modification to determine the barrier to proton transfer in the dimer. The results show that by lowering the temperature, the intensity of F1 decreased and that of that F2 increased.