University of Oulu

Zakharov, D. O., Chernichenko, K., Sorochkina, K., Repo, T., & Zhivonitko, V. V. (2022). Parahydrogen-induced polarization study of imine hydrogenations mediated by a metal-free catalyst. Dalton Transactions, 51(36), 13606–13611.

Parahydrogen-induced polarization study of imine hydrogenations mediated by a metal-free catalyst

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Author: Zakharov, Danila O.1; Chernichenko, Konstantin2; Sorochkina, Kristina1,2;
Organizations: 1NMR Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, Oulu, 90014, Finland
2Department of Chemistry, University of Helsinki, A. I. Virtasen Aukio 1, 00014 Helsinki, Finland
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Version: published version
Access: open
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Language: English
Published: Royal Society of Chemistry, 2022
Publish Date: 2022-10-25


Parahydrogen-induced polarization is a nuclear spin hyperpolarization technique that can provide strongly enhanced NMR signals for catalytic hydrogenation reaction products and intermediates. Among other matters, this can be employed to study the mechanisms of the corresponding chemical transformations. Commonly, noble metal complexes are used for reactions with parahydrogen. Herein, we present a PHIP study of metal-free imine hydrogenations catalyzed by the ansa-aminoborane catalyst QCAT. We discuss the reaction mechanism by showing the pairwise nature of the initial hydrogen activation step that leads to the formation of the negative net nuclear spin polarization of N–H hydrogen in the QCAT-H₂ intermediate, enabling the further transfer of parahydrogen-originating protons to the imine substrate with the accumulation of hyperpolarized amine products. Parahydrogen-induced polarization also demonstrates the reversibility of the catalytic cycle.

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Series: Dalton transactions
ISSN: 1477-9226
ISSN-E: 1477-9234
ISSN-L: 1477-9226
Volume: 51
Issue: 36
Pages: 13606 - 13611
DOI: 10.1039/d2dt02178a
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
Funding: This work was supported by the Academy of Finland (grant no. 323480) and the University of Oulu (Kvantum Institute). T. R. acknowledges the Academy of Finland for the financial support (grant no. 276586). The authors thank Dr Victor Sumerin (the University of Helsinki, former member) for the synthesis of the QCAT catalyst.
Academy of Finland Grant Number: 323480
Detailed Information: 323480 (Academy of Finland Funding decision)
Copyright information: © The Royal Society of Chemistry 2022. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence