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Heavy-Atom Tunneling in the Covalent/Dative Bond Complexation of Cyclo[18]carbon–Piperidine

[Image: see text] Recent quantum chemical computations demonstrated the electron-acceptance behavior of this highly reactive cyclo[18]carbon (C(18)) ring with piperidine (pip). The C(18)–pip complexation exhibited a double-well potential along the N–C reaction coordinate, forming a van der Waals (vd...

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Autores principales: Nandi, Ashim, Martin, Jan M. L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8900127/
https://www.ncbi.nlm.nih.gov/pubmed/35180344
http://dx.doi.org/10.1021/acs.jpcb.2c00218
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author Nandi, Ashim
Martin, Jan M. L.
author_facet Nandi, Ashim
Martin, Jan M. L.
author_sort Nandi, Ashim
collection PubMed
description [Image: see text] Recent quantum chemical computations demonstrated the electron-acceptance behavior of this highly reactive cyclo[18]carbon (C(18)) ring with piperidine (pip). The C(18)–pip complexation exhibited a double-well potential along the N–C reaction coordinate, forming a van der Waals (vdW) adduct and a more stable, strong covalent/dative bond (DB) complex by overcoming a low activation barrier. By means of direct dynamical computations using canonical variational transition state theory (CVT), including the small-curvature tunneling (SCT), we show the conspicuous role of heavy atom quantum mechanical tunneling (QMT) in the transformation of vdW to DB complex in the solvent phase near absolute zero. Below 50 K, the reaction is entirely driven by QMT, while at 30 K, the QMT rate is too rapid (k(T) ∼ 0.02 s(–1)), corresponding to a half-life time of 38 s, indicating that the vdW adduct will have a fleeting existence. We also explored the QMT rates of other cyclo[n]carbon–pip systems. This study sheds light on the decisive role of QMT in the covalent/DB formation of the C(18)–pip complex at cryogenic temperatures.
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spelling pubmed-89001272022-03-08 Heavy-Atom Tunneling in the Covalent/Dative Bond Complexation of Cyclo[18]carbon–Piperidine Nandi, Ashim Martin, Jan M. L. J Phys Chem B [Image: see text] Recent quantum chemical computations demonstrated the electron-acceptance behavior of this highly reactive cyclo[18]carbon (C(18)) ring with piperidine (pip). The C(18)–pip complexation exhibited a double-well potential along the N–C reaction coordinate, forming a van der Waals (vdW) adduct and a more stable, strong covalent/dative bond (DB) complex by overcoming a low activation barrier. By means of direct dynamical computations using canonical variational transition state theory (CVT), including the small-curvature tunneling (SCT), we show the conspicuous role of heavy atom quantum mechanical tunneling (QMT) in the transformation of vdW to DB complex in the solvent phase near absolute zero. Below 50 K, the reaction is entirely driven by QMT, while at 30 K, the QMT rate is too rapid (k(T) ∼ 0.02 s(–1)), corresponding to a half-life time of 38 s, indicating that the vdW adduct will have a fleeting existence. We also explored the QMT rates of other cyclo[n]carbon–pip systems. This study sheds light on the decisive role of QMT in the covalent/DB formation of the C(18)–pip complex at cryogenic temperatures. American Chemical Society 2022-02-18 2022-03-03 /pmc/articles/PMC8900127/ /pubmed/35180344 http://dx.doi.org/10.1021/acs.jpcb.2c00218 Text en © 2022 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Nandi, Ashim
Martin, Jan M. L.
Heavy-Atom Tunneling in the Covalent/Dative Bond Complexation of Cyclo[18]carbon–Piperidine
title Heavy-Atom Tunneling in the Covalent/Dative Bond Complexation of Cyclo[18]carbon–Piperidine
title_full Heavy-Atom Tunneling in the Covalent/Dative Bond Complexation of Cyclo[18]carbon–Piperidine
title_fullStr Heavy-Atom Tunneling in the Covalent/Dative Bond Complexation of Cyclo[18]carbon–Piperidine
title_full_unstemmed Heavy-Atom Tunneling in the Covalent/Dative Bond Complexation of Cyclo[18]carbon–Piperidine
title_short Heavy-Atom Tunneling in the Covalent/Dative Bond Complexation of Cyclo[18]carbon–Piperidine
title_sort heavy-atom tunneling in the covalent/dative bond complexation of cyclo[18]carbon–piperidine
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8900127/
https://www.ncbi.nlm.nih.gov/pubmed/35180344
http://dx.doi.org/10.1021/acs.jpcb.2c00218
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