Fast excited state dynamics in the isolated 7-azaindole-phenol H-bonded complex”

M. C. CAPELLO; M. BROQUIER; C. DEDONDER-LARDEUX; C. JOUVET; G. A. PINO

AMER INST PHYSICS

Lugar: New York; Año: 2013 vol. 138 p. 1 - 1

he excited state dynamics of the H-bonded 7-azaindole-phenol complex (7AI-PhOH) has been studied by combination of picosecond pump and probe experiments, LIF measurements on the nanosecond time scale and ab initio calculations. A very short S1 excited state lifetime (30 ps) has been measured for the complex upon excitation of the 000 transition and the lifetime remains unchanged when the ν6 vibrational mode (000+ 127 cm−1) is excited. In addition, no UV-visible fluorescence was observed by exciting the complex with nanosecond pulses. Two possible deactivation channels have been investigated by ab initio calculations: first an excited state tautomerization assisted by a concerted double proton transfer (CDPT) and second an excited state concerted proton electron transfer (CPET) that leads to the formation of a radical pair (hydrogenated 7AIH• radical and phenoxy PhO• radical). Both channels, CDPT and CPET, seem to be opened according to the ab initio calculations. However, t