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Switch Chemistry at Cryogenic Conditions: Quantum Tunnelling under Electric Fields

preprint
submitted on 16.11.2020, 11:27 and posted on 17.11.2020, 06:11 by Omer Kirshenboim, Alexander Frenklah, Sebastian Kozuch
While the influence of intramolecular electric fields is a known feature in enzymes, the use of oriented external electric fields (EEF) to enhance or inhibit molecular reactivity is a promising topic still in its infancy. Herein we will explore computationally the effects that EEF can provoke in simple molecules close to the absolute zero, where quantum tunnelling (QT) is the sole mechanistic option. We studied three exemplary systems, each one with different reactivity features and known QT kinetics:  bond-shifting in pentalene, Cope rearrangement in semibullvalene, and cycloreversion of diazabicyclohexadiene. The kinetics of these cases depdend both on the field strength and its direction, usually giving subtle but remarkable changes. However, for the cycloreversion, which suffers large changes on the dipole through the reaction, we also observed striking results. Between the effects caused by the EEF on the QT we observed an inversion of the Arrhenius equation, deactivation of the molecular fluxionality, and stabilization or instantaneous decomposition of the system. All these effects may well be achieved, literally, at the flick of a switch.

Funding

Israel Science Foundation 841/19

History

Email Address of Submitting Author

kozuch@bgu.ac.il

Institution

Ben-Gurion University of the Negev

Country

Israel

ORCID For Submitting Author

0000-0003-3070-8141

Declaration of Conflict of Interest

There are no conflicts of interest.

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