TY - JOUR
T1 - Spectroscopic studies of the conformations of n-decamethyltetrasilane
AU - Ernst, Chariya A.
AU - Allred, A. Louis
AU - Ratner, Mark A.
N1 - Funding Information:
This research was partially supported by the National Science Foundation (Grant No. CHE 76-10328). The use of the Central Facilities of Northwestern University’s Materials Research Center, supported under the NSF-MRL program grant DMR 76-80847, facilitated this work. We thank Professor D.F. Shriver for helpful discussions and for the use of Program RAMAN. We thank I-Ssuer Chuang for assistance with the NMRCTL computer program.
PY - 1979/9/25
Y1 - 1979/9/25
N2 - The conformational properties of n-decamethyltetrasilane, n-Si4(CH3)10, have been studied by variable temperature NMR (1H and 13C) and vibrational (IR and Raman) spectroscopy. As in related alkane systems, the anti conformer is more stable than the gauche conformer. Values of △H0 and △S0 for the anti → gauche reaction are 2.26 ± 0.15 kJ mol-1 and △S0 = 7.82± 0.86 J K-1mol-1, respectively. Thus, the two conformers are present in comparable quantities at room temperature. At very low temperatures, broadening of the two proton resonances (SiMe2, SiMe3) occurs, but phase changes precluded the observation of decoalescence. By approximate lineshape anaylysis, the free energy of activation, △G‡, for rotation about the central SiSi bond is estimated to be ∼25 kJ mol-1.
AB - The conformational properties of n-decamethyltetrasilane, n-Si4(CH3)10, have been studied by variable temperature NMR (1H and 13C) and vibrational (IR and Raman) spectroscopy. As in related alkane systems, the anti conformer is more stable than the gauche conformer. Values of △H0 and △S0 for the anti → gauche reaction are 2.26 ± 0.15 kJ mol-1 and △S0 = 7.82± 0.86 J K-1mol-1, respectively. Thus, the two conformers are present in comparable quantities at room temperature. At very low temperatures, broadening of the two proton resonances (SiMe2, SiMe3) occurs, but phase changes precluded the observation of decoalescence. By approximate lineshape anaylysis, the free energy of activation, △G‡, for rotation about the central SiSi bond is estimated to be ∼25 kJ mol-1.
UR - http://www.scopus.com/inward/record.url?scp=0000051005&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0000051005&partnerID=8YFLogxK
U2 - 10.1016/S0022-328X(00)87865-1
DO - 10.1016/S0022-328X(00)87865-1
M3 - Article
AN - SCOPUS:0000051005
SN - 0022-328X
VL - 178
SP - 119
EP - 131
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
IS - 1
ER -