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Unusual conformational preferences of 1,3-dimethyl-3-isopropoxy-3-silapiperidine
- The conformational analysis of the first representative of the Si-alkoxy substituted six-membered Si,N-heterocycles, 1,3-dimethyl-3-isopropoxy-3-silapiperidine, was performed by low-temperature 1H and 13C NMR spectroscopy and DFT theoretical calculations. In contrast to the expectations from the conformational energies of methyl and alkoxy substituents, the Meaxi-PrOeq conformer was found to predominate in the conformational equilibrium in the ratio Meaxi-PrOeq : Meeqi-PrOax of ca. 2 : 1 as from the 1H and 13C NMR study. The thermodynamic parameters obtained by the complete line shape analysis showed that the main contribution to the barrier to ring inversion originates from the entropy term of the free energy of activation.
Author details: | Svetlana V. Kirpichenko, Bagrat A. Shainyan, Erich KleinpeterORCiDGND |
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DOI: | https://doi.org/10.1002/poc.3028 |
ISSN: | 0894-3230 |
Title of parent work (English): | Journal of physical organic chemistry |
Publisher: | Wiley-Blackwell |
Place of publishing: | Hoboken |
Publication type: | Article |
Language: | English |
Year of first publication: | 2012 |
Publication year: | 2012 |
Release date: | 2017/03/26 |
Tag: | DFT theoretical calculations; barrier to ring inversion; conformational equilibrium; dynamic NMR; silapiperidines |
Volume: | 25 |
Issue: | 12 |
Number of pages: | 7 |
First page: | 1321 |
Last Page: | 1327 |
Funding institution: | Russian Foundation for Basic Research; Deutsche Forschungsgemeinschaft [11-03-91334] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie |
Peer review: | Referiert |