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Parahydrogen‐Induced Polarization in Hydrogenation Reactions Mediated by a Metal‐Free Catalyst
Author(s) -
Zakharov Danila O.,
Chernichenko Konstantin,
Sorochkina Kristina,
Yang Shengjun,
Telkki VilleVeikko,
Repo Timo,
Zhivonitko Vladimir V.
Publication year - 2022
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202103501
Subject(s) - spin isomers of hydrogen , hyperpolarization (physics) , alkene , alkyne , catalysis , chemistry , intramolecular force , photochemistry , frustrated lewis pair , induced polarization , polarization (electrochemistry) , hydrogen , lewis acids and bases , stereochemistry , nuclear magnetic resonance spectroscopy , organic chemistry , physics , quantum mechanics , electrical resistivity and conductivity
We report nuclear spin hyperpolarization of various alkenes achieved in alkyne hydrogenations with parahydrogen over a metal‐free hydroborane catalyst (HCAT). Being an intramolecular frustrated Lewis pair aminoborane, HCAT utilizes a non‐pairwise mechanism of H 2 transfer to alkynes that normally prevents parahydrogen‐induced polarization (PHIP) from being observed. Nevertheless, the specific spin dynamics in catalytic intermediates leads to the hyperpolarization of predominantly one hydrogen in alkene. PHIP enabled the detection of important HCAT‐alkyne‐H 2 intermediates through substantial 1 H, 11 B and 15 N signal enhancement and allowed advanced characterization of the catalytic process.