| Autor: |
Gololobov, Yu., Galkin, V., Petrovskii, P., Linchenko, O., Zueva, E., Mubarakova, L., Cherkasov, R., Schmutzler, R., Ernst, L., Jones, P., Freytag, M. |
| Zdroj: |
Russian Chemical Bulletin; September 2003, Vol. 52 Issue: 9 p1920-1927, 8p |
| Abstrakt: |
Studies by 1H NMR spectroscopy and X-ray diffraction analysis revealed hindered rotation of the aromatic substituent about the CAr—N bond in ortho-substituted (except for o-fluorine-substituted) phosphorus-containing carbamates. The energy barriers to rotation (ΔGc≠) and coalescence temperatures (Tc) determined by the coalescence method increase with increasing volume of the orthosubstituent. Conformations resulting from rotation of the ortho-substituted aryl group about the CAr—N bond were analyzed by quantum-chemical methods, potential curves were constructed, and differences between the conformational energies and the heights of rotation barriers were estimated. The theoretical rotation barriers change in parallel with the experimental values of ΔGc≠; however, the theoretical values are much smaller in magnitude. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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