@article{KirpichenkoShainyanKleinpeter2012,
  author    = {Kirpichenko, Svetlana V. and Shainyan, Bagrat A. and Kleinpeter, Erich},
  title     = {Unusual conformational preferences of 1,3-dimethyl-3-isopropoxy-3-silapiperidine},
  series = {Journal of physical organic chemistry},
  volume    = {25},
  journal   = {Journal of physical organic chemistry},
  number    = {12},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0894-3230},
  doi       = {10.1002/poc.3028},
  pages     = {1321 -- 1327},
  year      = {2012},
  abstract  = {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.},
  language  = {en}
}
@article{ShainyanSuslovaKleinpeter2012,
  author    = {Shainyan, Bagrat A. and Suslova, Elena N. and Kleinpeter, Erich},
  title     = {Conformational analysis of 4,4-dimethyl-1-(trifluoromethylsulfonyl)-1,4-azasilinane and 2,2,6,6-tetramethyl-4-(trifluoromethylsulfonyl)-1,4,2,6-oxazadisilinane},
  series = {Journal of physical organic chemistry},
  volume    = {25},
  journal   = {Journal of physical organic chemistry},
  number    = {1},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0894-3230},
  doi       = {10.1002/poc.1882},
  pages     = {83 -- 90},
  year      = {2012},
  abstract  = {4,4-Dimethyl-1-(trifluoromethylsulfonyl)-1,4-azasilinane 1 and 2,2,6,6-tetramethyl-4-(trifluoromethylsulfonyl)-1,4,2,6-oxazadisilinane 2 were studied by variable temperature dynamic 1H, 13C, 19F NMR spectroscopy and theoretical calculations at the DFT (density functional theory) and MP2 (Moller-Plesset 2) levels of theory. Both kinetic (barriers to ring inversion) and thermodynamic data (frozen conformational equilibria) could be obtained for the two compounds. The computations revealed two minima on the potential energy surface for molecules 1 and 2 corresponding to the rotamers with the CF3SO2 group directed inward and outward the ring, the latter being 0.20.4 kcal/mol (for 1) and 1.1 kcal/mol (for 2) more stable than the former. The vibrational calculations at the DFT and MP2 levels of theory give the values of the free energy difference Delta G degrees for the 'inward' reversible arrow 'outward' equilibrium consistent with those determined from the experimentally measured ratio of the rotamers. The structure of crystalline compound 2 was ascertained by X-ray diffraction analysis.},
  language  = {en}
}