Universität zu Köln

Paul, Mathias ORCID: 0000-0003-4635-3605, Peckelsen, Katrin, Thomulka, Thomas, Neudoerfl, Joerg, Martens, Jonathan ORCID: 0000-0001-9537-4117, Berden, Giel ORCID: 0000-0003-1500-922X, Oomens, Jos ORCID: 0000-0002-2717-1278, Berkessel, Albrecht ORCID: 0000-0003-0470-7428, Meijer, Anthony J. H. M. and Schaefer, Mathias (2019). Hydrogen tunneling avoided: enol-formation from a charge-tagged phenyl pyruvic acid derivative evidenced by tandem-MS, IR ion spectroscopy and theory. Phys. Chem. Chem. Phys., 21 (30). S. 16591 - 16601. CAMBRIDGE: ROYAL SOC CHEMISTRY. ISSN 1463-9084

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Abstract

A charge-tagged phenyl pyruvic acid derivative was investigated by tandem-MS, infrared (IR) ion spectroscopy and theory. The tailor-made precursor ions efficiently lose CO2 in collision induced dissociation (CID) experiments, offering access to study the secondary decay reactions of the product ions. IR ion spectroscopy provides evidence for the formation of an enol acid precursor ion structure in the gas phase and indicates the presence of enol products formed after CO2 loss. Extensive DFT computations however, suggest intermediate generation of hydroxycarbene products, which in turn rearrange in a secondary process to the enol ions detected by IR ion spectroscopy. Quantum mechanical tunneling of the hydroxycarbene can be excluded since no evidence for aldehyde product ion formation could be found. This finding is in contrast to the behavior of methylhydroxycarbene, which cleanly penetrates the energy barrier to form exclusively acetaldehyde at cryogenic temperatures in an argon matrix via quantum mechanical hydrogen tunneling. The results presented here are attributed to the highly excited energy levels of the product ions formed by CID in combination with different barrier heights of the competing reaction channels, which allow exclusive access over one energy barrier leading to the formation of the enol tautomer ions observed.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Paul, Mathias UNSPECIFIED orcid.org/0000-0003-4635-3605 UNSPECIFIED Peckelsen, Katrin UNSPECIFIED UNSPECIFIED UNSPECIFIED Thomulka, Thomas UNSPECIFIED UNSPECIFIED UNSPECIFIED Neudoerfl, Joerg UNSPECIFIED UNSPECIFIED UNSPECIFIED Martens, Jonathan UNSPECIFIED orcid.org/0000-0001-9537-4117 UNSPECIFIED Berden, Giel UNSPECIFIED orcid.org/0000-0003-1500-922X UNSPECIFIED Oomens, Jos UNSPECIFIED orcid.org/0000-0002-2717-1278 UNSPECIFIED Berkessel, Albrecht UNSPECIFIED orcid.org/0000-0003-0470-7428 UNSPECIFIED Meijer, Anthony J. H. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schaefer, Mathias UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-144317
DOI:	10.1039/c9cp02316j
Journal or Publication Title:	Phys. Chem. Chem. Phys.
Volume:	21
Number:	30
Page Range:	S. 16591 - 16601
Date:	2019
Publisher:	ROYAL SOC CHEMISTRY
Place of Publication:	CAMBRIDGE
ISSN:	1463-9084
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 GAS-PHASE; IRMPD SPECTROSCOPY; CHEMICAL-REACTIONS; MASS-SPECTROMETRY; BASIS-SETS; REACTIVITY; COMPLEXES; GENERATION; UMPOLUNG; MODEL Multiple languages Chemistry, Physical; Physics, Atomic, Molecular & Chemical Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/14431