On the electronic properties of a pH-responsive molecular thread for H-shaped molecular shuttles in aqueous solution

Abstract

A molecular thread composed by Tolyl-Viologen-Phenylene-Imidazole (T-VPI) subunits is investigated in a neutral aqueous environment and under acid conditions (T-VPI-H⁺) by classical molecular dynamics and a hybrid quantum mechanical/molecular mechanics approach. Nanosolvation patterns and UV/Vis spectroscopic properties for both T-VPI and T-VPI-H⁺ synthetic systems are characterized by analysing classical configurations with a QM(TD-DFT)/MM+C-PCM decomposition model. The derived aqueous UV/Vis absorptions support experimental observations under equilibrium conditions at 298 K while shedding light on the electronic degrees of freedom involved in the electronic excitations.