Universität zu Köln

Schaefer, Mathias, Peckelsen, Katrin, Paul, Mathias, Martens, Jonathan ORCID: 0000-0001-9537-4117, Oomens, Jos ORCID: 0000-0002-2717-1278, Berden, Giel, Berkessel, Albrecht ORCID: 0000-0003-0470-7428 and Meijer, Anthony J. H. M. (2017). Hydrogen Tunneling above Room Temperature Evidenced by Infrared Ion Spectroscopy. J. Am. Chem. Soc., 139 (16). S. 5779 - 5787. WASHINGTON: AMER CHEMICAL SOC. ISSN 0002-7863

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Abstract

While hydrogen tunneling at elevated temperatures has, for instance, often been postulated in biochemical processes, spectroscopic proof is thus far limited to cryogenic conditions, under which thermal reactivity is negligible. We report spectroscopic evidence for H-tunneling in the gas phase at temperatures around 320-350 K observed in the isomerization reaction of a hydroxycarbene into an aldehyde. The charge-tagged carbene was generated in situ in a tandem mass spectrometer by decarboxylation of oxo [4-(trimethylammonio)phenyl] acetic acid upon collision induced dissociation. All ion structures involved are characterized by infrared ion spectroscopy and quantum chemical calculations. The charge-tagged phenylhydroxycarbene undergoes a 1,2-H-shift to the corresponding aldehyde with an half-life of about 10 s, evidenced by isomer-selective two-color (IR-IR) spectroscopy. In contrast, the deuterated (OD) carbene analogue showed much reduced 1,2-D-shift reactivity with an estimated half-life of at least 200 s under the experimental conditions, and provides clear evidence for hydrogen atom tunneling in the H-isotopologue. This is the first spectroscopic confirmation of hydrogen atom tunneling governing 1,2-H-shift reactions at noncryogenic temperatures, which is of broad significance for a range of (bio)chemical processes, including enzymatic transformations and organocatalysis.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Schaefer, Mathias UNSPECIFIED UNSPECIFIED UNSPECIFIED Peckelsen, Katrin UNSPECIFIED UNSPECIFIED UNSPECIFIED Paul, Mathias UNSPECIFIED UNSPECIFIED UNSPECIFIED Martens, Jonathan UNSPECIFIED orcid.org/0000-0001-9537-4117 UNSPECIFIED Oomens, Jos UNSPECIFIED orcid.org/0000-0002-2717-1278 UNSPECIFIED Berden, Giel UNSPECIFIED UNSPECIFIED UNSPECIFIED Berkessel, Albrecht UNSPECIFIED orcid.org/0000-0003-0470-7428 UNSPECIFIED Meijer, Anthony J. H. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-233698
DOI:	10.1021/jacs.6b10348
Journal or Publication Title:	J. Am. Chem. Soc.
Volume:	139
Number:	16
Page Range:	S. 5779 - 5787
Date:	2017
Publisher:	AMER CHEMICAL SOC
Place of Publication:	WASHINGTON
ISSN:	0002-7863
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Organic Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language TRAP MASS-SPECTROMETER; AUXILIARY BASIS-SETS; GAS-PHASE; COMPLEXES; CHEMISTRY; CATALYSIS; ENZYMES Multiple languages Chemistry, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/23369