Abstract
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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References
Bourissou, D., Guerret, O., Gabbaï, F. P. & Bertrand, G. Stable carbenes. Chem. Rev. 100, 39–91 (2000)
Nolan, S. P. N-Heterocyclic Carbenes in Synthesis (Wiley-VCH, Weinheim, 2006)
Kemper, M. J. H., Vandijk, J. M. F. & Buck, H. M. Ab initio calculation on the photochemistry of formaldehyde. The search for a hydroxycarbene intermediate. J. Am. Chem. Soc. 100, 7841–7846 (1978)
Lucchese, R. R. & Schaefer, H. F. Metal-carbene complexes and the possible role of hydroxycarbene in formaldehyde laser photochemistry. J. Am. Chem. Soc. 100, 298–299 (1978)
Hoffmann, M. R. & Schaefer, H. F. Hydroxycarbene (HCOH) and protonated formaldehyde: Two potentially observable interstellar molecules. Astrophys. J. 249, 563–565 (1981)
Reid, D. L., Hernández-Trujillo, J. & Warkentin, J. A theoretical study of hydroxycarbene as a model for the homolysis of oxy- and dioxycarbenes. J. Phys. Chem. A 104, 3398–3405 (2000)
Goddard, J. D. & Schaefer, H. F. The photodissociation of formaldehyde: Potential energy surface features. J. Chem. Phys. 70, 5117–5134 (1979)
Baly, E. C. C., Heilbron, I. M. & Barker, W. F. CX.—Photocatalysis. Part I. The synthesis of formaldehyde and carbohydrates from carbon dioxide and water. J. Chem. Soc. Trans. 119, 1025–1035 (1921)
Sierra, M. A. Di- and polymetallic heteroatom stabilized (Fischer) metal carbene complexes. Chem. Rev. 100, 3591–3637 (2000)
Pau, C.-F. & Hehre, W. J. Relative thermochemical stabilities of hydroxymethylene and formaldehyde by ion cyclotron double resonance spectroscopy. J. Phys. Chem. 86, 1252–1253 (1982)
Fischer, E. O. & Maasböl, A. On existence of tungsten carbonyl carbene complex. Angew. Chem. Int. Edn Engl. 3, 580–581 (1964)
Weiner, B. R. & Rosenfeld, R. N. Pyrolysis of pyruvic acid in the gas phase. A study of the isomerization mechanism of a hydroxycarbene intermediate. J. Org. Chem. 48, 5362–5364 (1983)
Rosenfeld, R. N. & Weiner, B. Energy disposal in the photofragmentation of pyruvic acid in the gas phase. J. Am. Chem. Soc. 105, 3485–3488 (1983)
Jacox, M. E. The spectroscopy of molecular reaction intermediates trapped in the solid rare gases. Chem. Soc. Rev. 31, 108–115 (2002)
Evangelista, F. A., Allen, W. D. & Schaefer, H. F. Coupling term derivation and general implementation of state-specific multireference coupled cluster theories. J. Chem. Phys. 127, 024102 (2007)
Császár, A. G., Allen, W. D. & Schaefer, H. F. In pursuit of the ab initio limit for conformational energy prototypes. J. Chem. Phys. 108, 9751–9764 (1998)
Schreiner, P. R. & Reisenauer, H. P. The “non-reaction” of ground-state triplet carbon atoms with water revisited. ChemPhysChem 7, 880–885 (2006)
Venkateswarlu, P. & Gordy, W. Methyl alcohol II. Molecular structure. J. Chem. Phys. 23, 1200–1202 (1955)
Reisenauer, H. P., Romanski, J., Mloston, G. & Schreiner, P. R. Dimethoxycarbene: Conformational analysis of a reactive intermediate. Eur. J. Org. Chem. 4813–4818 (2006)
Sodeau, J. R. & Lee, E. K. C. Intermediacy of hydroxymethylene (HCOH) in the low temperature matrix photochemistry of formaldehyde. Chem. Phys. Lett. 57, 71–74 (1978)
Miller, W. H. Tunneling corrections to unimolecular rate constants, with application to formaldehyde. J. Am. Chem. Soc. 101, 6810–6814 (1979)
Miller, W. H., Handy, N. C. & Adams, J. E. Reaction path Hamiltonian for polyatomic molecules. J. Chem. Phys. 72, 99–112 (1980)
Carrington, T., Hubbard, L. M., Schaefer, H. F. & Miller, W. H. Vinylidene: Potential energy surface and unimolecular reaction dynamics. J. Chem. Phys. 80, 4347–4354 (1984)
Johnston, H. S. Gas Phase Reaction Rate Theory (Ronald Press, New York, 1966)
McMahon, R. J. & Chapman, O. L. Direct spectroscopic observation of intramolecular hydrogen shifts in carbenes. J. Am. Chem. Soc. 109, 683–692 (1987)
Zuev, P. S. & Sheridan, R. S. Tunneling in the C–H insertion of a singlet carbene: tert-Butylchlorocarbene. J. Am. Chem. Soc. 116, 4123–4124 (1994)
Pettersson, M. et al. Cis → trans conversion of formic acid by dissipative tunneling in solid rare gases: Influence of environment on the tunneling rate. J. Chem. Phys. 117, 9095–9098 (2002)
Maçôas, E. M. S., Khriachtchev, L., Pettersson, M., Fausto, R. & Räsänen, M. Rotational isomerism of acetic acid isolated in rare-gas matrices: Effect of medium and isotopic substitution on IR-induced isomerization quantum yield and cis → trans tunneling rate. J. Chem. Phys. 121, 1331–1338 (2004)
Zou, S., Bowman, J. M. & Brown, A. Full-dimensionality quantum calculations of acetylene–vinylidene isomerization. J. Chem. Phys. 118, 10012–10023 (2003)
Mátyus, E., Czakó, G., Sutcliffe, B. T. & Császár, A. G. Vibrational energy levels with arbitrary potentials using the Eckart-Watson Hamiltonians and the discrete variable representation. J. Chem. Phys. 127, 084102 (2007)
Allen, W. D., East, A. L. L. & Császár, A. G. in Structures and Conformations of Non-Rigid Molecules (eds Laane, J., Dakkouri, M., van der Veken, B. & Oberhammer, H.) 343–373 (NATO ASI Series C, Kluwer, Dordrecht, 1993)
Császár, A. G. et al. in Spectroscopy from Space (eds Demaison, J., Sarka, K. & Cohen, E. A.) 317–339 (NATO Science Series II, Vol. 20, Kluwer, Dordrecht, 2001)
Schuurman, M. S., Muir, S. R., Allen, W. D. & Schaefer, H. F. Toward subchemical accuracy in computational thermochemistry: Focal point analysis of the heat of formation of NCO and [H,N,C,O] isomers. J. Chem. Phys. 120, 11586–11599 (2004)
Gonzales, J. M. et al. Definitive ab initio studies of model SN2 reactions CH3X + F– (X = F, Cl, CN, OH, SH, NH2, PH2). Chem. Eur. J. 9, 2173–2192 (2003)
Dunning, T. H. Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen. J. Chem. Phys. 90, 1007–1023 (1989)
Woon, D. E. & Dunning, T. H. Jr. Gaussian basis sets for use in correlated molecular calculations. V. Core-valence basis sets for boron through neon. J. Chem. Phys. 103, 4572–4585 (1995)
Perera, A. S. & Bartlett, R. J. Relativistic effects at the correlated level. An application to interhalogens. Chem. Phys. Lett. 216, 606–612 (1993)
Balasubramanian, K. Relativistic Effects in Chemistry Part A, Theory and Techniques (Wiley, New York, 1997)
Tarczay, G., Császár, A. G., Klopper, W. & Quiney, H. M. Anatomy of relativistic energy corrections in light molecular systems. Mol. Phys. 99, 1769–1794 (2001)
Bomble, Y. J., Stanton, J. F., Kállay, M. & Gauss, J. Coupled-cluster methods including noniterative corrections for quadruple excitations. J. Chem. Phys. 123, 054101 (2005)
Kállay, M. & Gauss, J. Approximate treatment of higher excitations in coupled-cluster theory. J. Chem. Phys. 123, 214105 (2005)
Evangelista, F. A., Allen, W. D. & Schaefer, H. F. High-order excitations in state-universal and state-specific multireference coupled cluster theories: Model systems. J. Chem. Phys. 125, 154113 (2006)
Watson, J. K. G. in Vibrational Spectra and Structure, Vol. 6 (ed. Durig, J. R.) 1–89 (Elsevier, New York and Amsterdam, 1977)
Mills, I. M. in Molecular Spectroscopy: Modern Research (eds Rao, K. N. & Mathews, C. W.) 1–115 (Academic, New York, 1972)
Papoušek, D. & Aliev, M. R. Molecular Vibrational-Rotational Spectra (Elsevier, Amsterdam, 1982)
Nielsen, H. H. The vibration-rotation energies of molecules. Rev. Mod. Phys. 23, 90–136 (1951)
Clabo, D. A., Allen, W. D., Remington, R. B., Yamaguchi, Y. & Schaefer, H. F. A systematic study of molecular vibrational anharmonicity and vibration-rotation interaction by self-consistent-field higher-derivative methods. Asymmetric top molecules. Chem. Phys. 123, 187–239 (1988)
Allen, W. D. et al. A systematic study of molecular vibrational anharmonicity and vibration-rotation interaction by self-consistent-field higher-derivative methods. Linear polyatomic molecules. Chem. Phys. 145, 427–466 (1990)
Schuurman, M. S., Allen, W. D. & Schaefer, H. F. The ab initio limit quartic force field of BH3 . J. Comput. Chem. 26, 1106–1112 (2005)
DeKock, R. L. et al. The electronic structure and vibrational spectrum of trans-HNOO. J. Phys. Chem. A 108, 2893–2903 (2004)
Czakó, G., Furtenbacher, T., Császár, A. G. & Szalay, V. Variational vibrational calculations using high-order anharmonic force fields. Mol. Phys. 102, 2411–2423 (2004)
Fukui, K. A formulation of the reaction coordinate. J. Phys. Chem. 74, 4161–4163 (1970)
Gonzales, C. & Schlegel, H. B. Reaction path following in mass-weighted internal coordinates. J. Phys. Chem. 94, 5523–5527 (1990)
Allen, W. D., Bodi, A., Szalay, V. & Császár, A. G. Adiabatic approximations to internal rotation. J. Chem. Phys. 124, 224310 (2006)
Liboff, R. L. Introductory Quantum Mechanics (Addison-Wesley, Reading, Massachusetts, 2003)
Razavy, M. Quantum Theory of Tunneling (World Scientific, Singapore, 2003)
Gray, S. K., Miller, W. H., Yamaguchi, Y. & Schaefer, H. F. Reaction path Hamiltonian: Tunneling effects in the unimolecular isomerization HNC → HCN. J. Chem. Phys. 73, 2733–2739 (1980)
Acknowledgements
We are grateful for support from the Fonds der Chemischen Industrie, the US Department of Energy, and the Hungarian Scientific Research Fund. We thank J. Bowman and W. Miller for comments on the tunnelling analysis.
Author Contributions P.R.S. and H.P.R. formulated the initial working hypothesis and provided, analysed and interpreted all experimental data. F.C.P. and A.C.S. performed all the electronic structure computations under the direction of W.D.A. The variational vibrational computations were executed by E.M. under the guidance of A.G.C. and W.D.A. The tunnelling analysis was performed by W.D.A., with input from F.C.P. and A.C.S. The manuscript was primarily written by P.R.S. and W.D.A.
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The file contains Supplementary Figures and Legends 1 and 2; Supplementary Tables 1-10. The supplementary information contains two figures showing computed molecular structures with structural parameters. One supplementary experimental table summarizes the tunneling experiments at different temperatures and in different matrices. Another 9 supplementary tables contain computed data: xyz coordinates of all structures (supplementary tables 2 and 3) and energies (supplementary tables 4-10). (PDF 1347 kb)
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Schreiner, P., Reisenauer, H., Pickard IV, F. et al. Capture of hydroxymethylene and its fast disappearance through tunnelling. Nature 453, 906–909 (2008). https://doi.org/10.1038/nature07010
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DOI: https://doi.org/10.1038/nature07010
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