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 12.06.2008   Карта сайта     Language По-русски По-английски
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12.06.2008

Nature 453, 906-909 (12 June 2008) | doi:10.1038/nature07010; Received 25 November 2007; Accepted 16 April 2008



Capture of hydroxymethylene and its fast disappearance through tunnelling


Peter R. Schreiner1, Hans Peter Reisenauer1, Frank C. Pickard IV2, Andrew C. Simmonett2, Wesley D. Allen2, Edit Mátyus3 & Attila G. Császár3




  1. Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
  2. Center for Computational Chemistry and Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
  3. Laboratory of Molecular Spectroscopy, Institute of Chemistry, Eötvös University, H-1518 Budapest 112PO Box 32, Hungary


Correspondence to: Peter R. Schreiner1Wesley D. Allen2 Correspondence and requests for materials should be addressed to P.R.S. (Email: prs@org.chemie.uni-giessen.de) or W.D.A. (Email: wdallen@uga.edu).





Singlet carbenes exhibit a divalent carbon atom whose valence shell contains only six electrons, four involved in bonding to two other atoms and the remaining two forming a non-bonding electron pair. These features render singlet carbenes so reactive that they were long considered too short-lived for isolation and direct characterization. This view changed when it was found that attaching the divalent carbon atom to substituents that are bulky and/or able to donate electrons produces carbenes that can be isolated and stored1. N-heterocyclic carbenes are such compounds now in wide use, for example as ligands in metathesis catalysis2. In contrast, oxygen-donor-substituted carbenes are inherently less stable and have been less studied. The pre-eminent case is hydroxymethylene, H–C–OH; although it is the key intermediate in the high-energy chemistry of its tautomer formaldehyde3, 4, 5, 6, 7, has been implicated since 1921 in the photocatalytic formation of carbohydrates8, and is the parent of alkoxycarbenes that lie at the heart of transition-metal carbene chemistry, all attempts to observe this species or other alkoxycarbenes have failed9. However, theoretical considerations indicate that hydroxymethylene should be isolatable10. Here we report the synthesis of hydroxymethylene and its capture by matrix isolation. We unexpectedly find that H–C–OH rearranges to formaldehyde with a half-life of only 2 h at 11 K by pure hydrogen tunnelling through a large energy barrier in excess of 30 kcal mol–1.



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