Open access
Date
2022-08-15Type
- Journal Article
Abstract
We simulate two recent matrix-isolation experiments at cryogenic temperatures, in which a nitrene undergoes spin crossover from its triplet state to a singlet state via quantum tunnelling. We detail the failure of the commonly applied weak-coupling method (based on a linear approximation of the potentials) in describing these deep-tunnelling reactions. The more rigorous approach of semiclassical golden-rule instanton theory in conjunction with double-hybrid density-functional theory and multireference perturbation theory does, however, provide rate constants and kinetic isotope effects in good agreement with experiment. In addition, these calculations locate the optimal tunnelling pathways, which provide a molecular picture of the reaction mechanism. The reactions involve substantial heavy-atom quantum tunnelling of carbon, nitrogen and oxygen atoms, which unexpectedly even continues to play a role at room temperature. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000556495Publication status
publishedExternal links
Journal / series
Angewandte Chemie. International EditionVolume
Pages / Article No.
Publisher
Wiley-VCHSubject
Theoretical chemistry; Computational chemistry; Spin crossover; Quantum tunnelling; Ab initio calculations; Nitrenes; Instanton theoryOrganisational unit
09602 - Richardson, Jeremy / Richardson, Jeremy
Funding
207772 - Nonadiabatic effects in chemical reactions (SNF)
Related publications and datasets
Is new version of: https://doi.org/10.26434/chemrxiv-2022-2gcgx
Is referenced by: https://doi.org/10.3929/ethz-b-000612202
References: https://doi.org/10.3929/ethz-b-000518294
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