Year: 2024
Type: article
Abstract: Photoisomerization, the structural alteration of molecules upon absorption of light, is crucial for the function of biological chromophores such as retinal in opsins, proteins vital for vision and other light-sensitive processes. The intrinsic selectivity of this isomerization process (i.e., which double bond in the chromophore is isomerized) is governed by both the inherent properties of the chromophore and its surrounding environment. In this study, we employ the extended multistate complete active space second-order perturbation theory (XMS-CASPT2) method to investigate photoisomerization selectivity in linear conjugated chromophores, focusing on two simple molecular models resembling retinal. By analyzing electronic energies, intramolecular charge separation, and conical intersection topographies in the gas phase, we show that the photoproduct formed by rotation around the double bond near the Schiff base is energetically favored. The topographic differences at the conical intersections leading to different photoproducts reveal differences in photodynamics. In multiphoton excitation, the primary photoproduct typically reverts to the initial configuration rather than rotating around a different double bond. Our study offers new insights into the photodynamics of photoisomerizing double bonds in π-conjugated chromophores. We anticipate that our findings will provide valuable perspectives for advancing the understanding of biological chromophores and for designing efficient photochemical switches with applications in molecular electronics and phototherapy.
Source: ACS Physical Chemistry Au
Authors: Saumik Sen, Xavier Deupi
Language: English
Subfield: Physical and Theoretical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,879
Awards: International, Interdisciplinary & Intersectoral Postdoctoral Fellowships at the Paul Scherrer Institut, Structural determinants of recognition and selectivity in GPCR-G protein complexes, International, Interdisciplinary and Intersectoral Postdoctoral Fellowships at the Paul Scherrer Institut, G434337789, G5578714457
OpenAlex ID: W4403054913