Dynamics simulations of excited-state triple proton transfer in7-azaindole complexes with water, water-methanol and methanol

Abstract

Excited-state triple proton transfer (ESTPT) reactions in 7-azaindole (7AI) complexed with two water,with one water and one methanol, and with two methanol molecules were investigated by dynamicssimulations in the first excited state computed with the second order algebraic-diagrammatic construc-tion (ADC (2)) method. The results show that photoexcitation may trigger ultrafast an asynchronousconcerted proton transfer via two solvent molecules along an intermolecular hydrogen-bonded network.The probability of occurrence of ESTPT ranges from 32% for 7AI(H2O-MeOH) to 64% for 7AI(MeOH)2. Theaverage time for completing the ESTPT varies between 58 and 85 fs depending on the complex. The pro-ton transfer (rather than hydrogen transfer) nature of the reaction was suggested by the nonexistence ofcrossings between the ππ* and πσ* states. © 2013 Elsevier B.V.