- Identification and Reactivity of s- cis, s- cis-Dihydroxycarbene, a New [CH2O2] Intermediate
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We report the first preparation of the s-cis,s-cis conformer of dihydroxycarbene (1cc) by means of pyrolysis of oxalic acid, isolation of the lower-energy s-trans,s-trans (1tt) and s-cis,s-trans (1ct) product conformers at cryogenic temperatures in a N2 matrix, and subsequent narrow-band near-infrared (NIR) laser excitation to give 1cc. Carbene 1cc converts quickly to 1ct via quantum-mechanical tunneling with an effective half-life of 22 min at 3 K. The potential energy surface features around 1 were pinpointed by convergent focal point analysis targeting the AE-CCSDT(Q)/CBS level of electronic structure theory. Computations of the tunneling kinetics confirm the time scale of the 1cc → 1ct rotamerization and suggest that direct 1cc → H2 + CO2 decomposition may also be a minor pathway. The intriguing latter possibility cannot be confirmed spectroscopically, but hints of it may be present in the measured kinetic profiles.
- Quanz, Henrik,Bernhardt, Bastian,Erb, Frederik R.,Bartlett, Marcus A.,Allen, Wesley D.,Schreiner, Peter R.
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p. 19457 - 19461
(2020/12/18)
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- Spectroscopic identification of dihydroxycarbene
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Out and about: CO2 extrusion from simple α-keto carboxylic acids can be used to prepare hitherto unknown hydroxycarbenes. High-vacuum flash pyrolysis of oxalic acid or its monomethyl ester enabled the preparation and characterization of dihydro
- Schreiner, Peter R.,Reisenauer, Hans Peter
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supporting information; experimental part
p. 7071 - 7074
(2009/04/07)
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