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Conformational Analysis of (1,1′-Phenyl-1,1′-silacyclohex-1-yl)disiloxane. DFT and Low-Temperature 13C NMR Spectroscopy Study
Ist Teil von
Russian journal of general chemistry, 2019-04, Vol.89 (4), p.713-716
Ort / Verlag
Moscow: Pleiades Publishing
Erscheinungsjahr
2019
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
The DFT and MP2 theoretical conformational analysis of the recently synthesized (1,1′-phenyl-1,1′-silacyclohex-1-yl)disiloxane has revealed the energetic preference of the Ph
ax
,Ph
ax
conformer. The Ph
ax
,Ph
ax
: Ph
ax
,Ph
eq
: Ph
eq
,Ph
eq
conformers ratio has been estimated as of 46.6: 33.1: 20.3 from the M062X/6-311G(d,p) free energy simulation, suggesting the possibility of detecting individual conformers experimentally, e.g., by low-temperature
1
H and
13
C NMR spectroscopy. However, only the presence of several conformers has been detected by means of
1
H NMR spectroscopy at 113 K; determination of the Δν (Hz) and Δ
G
#
(kcal/mol) parameters for the 6-membered ring interconversion has been impossible due to the signals broadening at low temperature, signal temperature shifts, and extremely low barrier of ring inversion at
T
c
< 113 K.