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Deuterium and Hydrogen Tunneling in the Hydrogenation of 4‐Oxocyclohexa‐2,5‐dienylidene
Author(s) -
Henkel Stefan,
Ertelt Melanie,
Sander Wolfram
Publication year - 2014
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.201402064
Subject(s) - kinetic isotope effect , deuterium , chemistry , quantum tunnelling , hydrogen , carbene , electron paramagnetic resonance , photochemistry , infrared spectroscopy , intermolecular force , selectivity , spectroscopy , kinetic energy , ground state , materials science , atomic physics , molecule , nuclear magnetic resonance , catalysis , organic chemistry , physics , optoelectronics , quantum mechanics
4‐Oxocyclohexa‐2,5‐dienylidene is a highly reactive triplet ground state carbene that is hydrogenated in solid H 2 , HD, and D 2 at temperatures as low as 3 K. The mechanism of the insertion of the carbene into dihydrogen was investigated by IR and EPR spectroscopy and by kinetic studies. H or D atoms were observed as products of the reaction with H 2 and D 2 , respectively, whereas HD produces exclusively D atoms. The hydrogenation shows a very large kinetic isotope effect and remarkable isotope selectivity, as was expected for a tunneling reaction. The experiments, therefore, provide clear evidence for both hydrogen tunneling and the rare deuterium tunneling in an intermolecular reaction.