Work

Simulating the Energy Capture Process in Push–Pull Norbornadiene-Quadricyclane Photoswitches

Year: 2025

Type: article

Abstract: Molecular switches based on the norbornadiene-quadricyclane (NBD-QC) isomer pair are among the most promising candidates for applications in molecular solar thermal energy storage (MOST). In these compounds, solar energy is captured through a photoinduced [2 + 2] cycloaddition reaction whose mechanism is only partially understood. This holds true especially for NBD derivatives containing the type of push-pull substitution pattern that was previously proven necessary to attain reasonable photoisomerization quantum yields. In the present contribution, we report a computational investigation of the photochemistry of NBD-QC switches with precisely such a substitution pattern. Static calculations provide information on the structures of the excited electronic states involved in the photoinduced cycloaddition reaction, and the topographies of the relevant ground- and excited-state potential energy surfaces. Furthermore, nonadiabatic molecular dynamics (NAMD) simulations allow an estimation of the reaction time scale and quantum yield. The simulation results paint a detailed picture of the energy capture process: the photoinduced cycloaddition reaction begins in the spectroscopically bright excited state of the molecular switch. In the model compound for which we performed NAMD simulations, ring closing takes place on a time scale of roughly 150 fs, which makes it one of the fastest known photoisomerization reactions.

Source: The Journal of Physical Chemistry Letters

DOI: 10.1021/acs.jpclett.5c00634

Authors: Michał Andrzej Kochman, Bo Durbeej

Institutions: Institute of Physical Chemistry, Ruhr University Bochum, Polish Academy of Sciences, Linköping University

Language: English

Topic: Photochromic and Fluorescence Chemistry

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,500