2,7-diazaindole as novel photophysical probe for solvent mediated excited state hydrogen/ proton transfer in the gas phase

Photoinduced tautomerization reactions have been the centre of attention among scientific community over past several decades because of their significance in various biological systems. 7-azaindole (7AI) is considered as a model system for DNA base pairing and to figure out the role of such tautomerization reactions in mutations. Extensive studies have been carried on 7-azaindole and its solvent clusters exhibiting proton/hydrogen transfer in both solution as well as gas phase. Derivatives of above molecule like 2,7- and 2,6-diazaindoles are proposed to have even better photophysical properties due to the presence of -aza group on the 2nd position. There are a few studies in the solution phase which suggest the relevance of these moleculesbut there are no experimental studies reported in the gas phase yet. In our current investigation on 2,7-diazaindole (2,7-DAI) and its solvent cluster (2,7-DAI-H₂O), we have employed state-of-the-art laser spectroscopic methods such as fluorescence excitation (LIF), dispersed fluorescence (DF), resonant two-photon ionization time of flight mass spectrometry (2C-R2PI) and photoionization efficiency spectroscopy (PIE) to understand the electronic structure of the molecule