Journal of Molecular Structure p. 31 - 47 (1999)
Update date:2022-08-11
Topics:
Durig, James R.
Yanping, Jin
Pengqian, Zhen
Gounev, Todor K.
Guirgis, Gamil A.
The infrared (3500-40 cm-1) spectra of gaseous and solid 1- methylsilacyclobutane, c-C3H6SiH(CH3), have been recorded. In addition, the Raman spectrum (3500-30 cm-1) of the liquid has also been recorded and quantitative depolarization values obtained. Both the axial and equatorial conformers, with respect to methyl group, have been identified in the fluid phases. Variable temperature studies (-55 to - 100°C) of the infrared spectra of the sample dissolved in liquid xenon have been carried out. From these data, the enthalpy difference has been determined to be 122 ± 26 cm- 1 (1.46 ± 0.32 kJ/mol), with the equatorial conformer being the more stable structure. However, with repeated annealing of the amorphous solid, it was not possible to obtain a polycrystalline solid with a single conformer. A complete vibrational assignment is proposed for the equatorial conformer based on infrared band contours, relative intensities, depolarization values and group frequencies. Most of the fundamentals for the axial conformer have also been identified. Utilizing the frequency of the silicon-hydrogen (Si-H) stretching mode, the Si-H distance has been determined to be 1.490 A for both conformers. The vibrational assignments are supported by normal coordinate calculations utilizing ab initio force constants. Complete equilibrium geometries have been determined for both rotamers by ab initio calculations, employing the 3-21G* and 6-31G* basis sets at the levels of restricted Hartree-Fock (RHF) and/or Moller-Plesset (MP) to second order. The results are discussed and compared with those obtained for some similar molecules.
View MoreJiYi Chemical (Beijing) Co., Ltd.
Contact:+86-10-89385733
Address:Shilou Town of Fangshan District, Beijing
Contact:+86-27-87204219, +86-27-87215023
Address:2402, HuiGu Space-time Building, 8 Forest Road, East Lake Hi-Tech Development Zone
Shandong Dayi Chemical Co., Ltd.
website:http://www.dayi.com.cn
Contact:+86- 535-7388728. 15306386031
Address:No 1 Danya west road, Laiyang City, Shandong province
CHANGZHOU HANGYU PHARMACEUTICAL TECHNOLOGY CO., LTD
website:http://www.czyys.com
Contact:0086-519-88802789
Address:No.300,Yanling Middle Road, Changzhou, Jiangsu, China
Chemvon Biotechnology Co. Ltd.
website:http://www.chemvon.com
Contact:86-21-58550039;86-21-31268550-8004
Address:Suite B-10#, 6999 Chuansha Road, Pudong District, Shanghai 201202, China
Doi:10.1016/S0040-4039(01)92387-1
(1981)Doi:10.1021/jacs.9b06896
(2019)Doi:10.1166/jnn.2015.11272
(2015)Doi:10.1134/S0020168514090106
(2014)Doi:10.1016/j.tetlet.2005.01.036
(2005)Doi:10.1246/cl.1986.1611
(1986)