Characterization of a Triplet Vinylidene
| Autor: | Yury Kutin, Justus Reitz, Patrick W. Antoni, Anton Savitsky, Dimitrios A. Pantazis, Müge Kasanmascheff, Max M. Hansmann |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Journal of the American Chemical Society |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/jacs.1c11062 |
| Popis: | Singlet vinylidenes (R2C=C:) are proposed as intermediates in a series of organic reactions, and very few have been studied by matrix isolation or gas-phase spectroscopy. Triplet vinylidenes, however, featuring two unpaired electrons at a monosubstituted carbon atom are thus far only predicted as electronically excited-state species and represent an unexplored class of carbon-centered diradicals. We report the photochemical generation and low-temperature EPR/ENDOR characterization of the first ground-state high-spin (triplet) vinylidene. The zero-field splitting parameters (D = 0.377 cm–1 and |E|/D = 0.028) were determined, and the 13C hyperfine coupling tensor was obtained by 13C-ENDOR measurements. Most strikingly, the isotropic 13C hyperfine coupling constant (50 MHz) is far smaller than the characteristic values of triplet carbenes, demonstrating a unique electronic structure which is supported by quantum chemical calculations. |
| Databáze: | OpenAIRE |
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