Molecular dynamics and metadynamics simulations of [2 + 2] photocycloaddition
| Autor: | Radek Cibulka, Petr Slavíček, Eva Muchová, Michal Bezek, Jiří Suchan |
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| Rok vydání: | 2017 |
| Předmět: |
010304 chemical physics
Chemistry Ab initio Metadynamics 010402 general chemistry Condensed Matter Physics 01 natural sciences Atomic and Molecular Physics and Optics 0104 chemical sciences Cyclobutane Molecular dynamics chemistry.chemical_compound Intersystem crossing Ab initio quantum chemistry methods Computational chemistry 0103 physical sciences Physics::Chemical Physics Physical and Theoretical Chemistry Triplet state Ground state |
| Zdroj: | International Journal of Quantum Chemistry. 118:e25534 |
| ISSN: | 0020-7608 |
| Popis: | Triplet state mechanism of [2 + 2] photocycloaddition forming a cyclobutane ring from two ethylenes is investigated in the context of photocatalysis. High-level ab initio calculations are combined with ab initio adiabatic molecular dynamics and ab initio metadynamics for rare events modeling. In a photocatalytic scheme, a reactant reaches the triplet state either via intersystem crossing (ISC) or triplet sensitization. The model system adopts a biradical structure, which represents energy intersection with the ground state. The system either completes cyclization or undergoes fragmentation into two olefinic units. The potential and free energy surfaces of the cyclobutane/ethylenes system are mapped with multireference approaches describing possible reaction pathways. To obtain a full picture of a double bond photoreactivity, ab initio adiabatic dynamical calculations were used to estimate reaction yields and to model the effects of excess energy. The potential use of density functional theory based approaches for [2 + 2] photocycloaddition was investigated for future simulations and design of realistic photocatalytic systems. Dynamical aspects of [2 + 2] photocycloaddition via a triplet state manifold are investigated by combining ab initio multireference methods and ab initio molecular dynamics and metadynamics. The reaction pathways are studied for a model system of two ethylenes forming a cyclobutane ring to provide a basis for further studies on design of photocatalytic systems. |
| Databáze: | OpenAIRE |
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