Control of excited state charge transfer dynamics of DMABN in deep eutectic solvent: Involvement of the partially twisted intermediate state

The photo-driven charge transfer process of 4-(dimethylamino) benzonitrile (DMABN) in deep eutectic solvent (DES) is investigated through steady state and time resolved spectroscopy along with non -adiabatic molecular dynamic simulations. Simultaneous coexistence of polar and non-polar domains in the DES manifests itself in different optical response and charge transfer dynamics of DMABN. The weaker correlation between solvent viscosity and observed reaction dynamics reveals the inadequacy of global macroscopic variables to rationalise the process at the microscopic level. On the other hand, ab initio computational results clearly show the presence of a distribution of partially twisted conforma-tions, that helps to rationalise the experimental observations.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).