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Torsionally broken symmetry assists infrared excitation of biomimetic charge-coupled nuclear motions in the electronic ground state Featured

authors
Gourab Chatterjee, Ajay Jha, Alejandro Blanco-Gonzalez, Vandana Tiwari, Madushanka Manathunga, Hong-Guang Duan, Friedjof Tellkamp, Valentyn I. Prokhorenko, Nicolas Ferré, Jyotishman Dasgupta, Massimo Olivucci and R. J. Dwayne Miller
date published
July 19, 2022
journal
Chemical Science
volume, number
13
pages
9392-9400
doi
https://doi.org/10.1039/D2SC02133A
abstract

The concerted interplay between reactive nuclear and electronic motions in molecules actuates chemistry. Here, we demonstrate that out-of-plane torsional deformation and vibrational excitation of stretching motions in the electronic ground state modulate the charge-density distribution in a donor-bridge-acceptor molecule in solution. The vibrationally-induced change, visualised by transient absorption spectroscopy with a mid-infrared pump and a visible probe, is mechanistically resolved by ab initio molecular dynamics simulations. Mapping the potential energy landscape attributes the observed charge-coupled coherent nuclear motions to the population of the initial segment of a double-bond isomerization channel, also seen in biological molecules. Our results illustrate the pivotal role of pre-twisted molecular geometries in enhancing the transfer of vibrational energy to specific molecular modes, prior to thermal redistribution. This motivates the search for synthetic strategies towards achieving potentially new infrared-mediated chemistry.