کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9770380 | 1501947 | 2005 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Observation of various conformers of 4-cyano-4â²-alkylbiphenyl by IR spectroscopy and density functional theory calculations
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Infrared (IR) absorption spectra of 4-cyano-4â²-alkylbiphenyls (nCBs; 1â¤nâ¤5) with various alkyl chain conformations were calculated with density functional theory (DFT) of B3LYP/6-31G(d) level. Normal coordinate analysis base on the results of DFT calculations were also carried out. Calculated spectral patterns of phenyl ring C-H out-of-plane (CHOOP) deformation modes in the 880-750 cmâ1 region, which are coupled with C-H rocking and C-C stretching vibrations of alkyl chain, show marked differences with conformational changes in alkyl chains. The observed IR spectral patterns of CHOOP bands in nCBs (3â¤nâ¤5) are well explained by the overlap of the calculated spectra of possible conformers. The peak wavenumber shifts and intensity changes of the observed spectra in this region with phase transition from isotropic (40 °C) to nematic (25 °C) phase for 5CB are also well explained by the population changes within possible 5CB conformers.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure - Volumes 735â736, 14 February 2005, Pages 27-37
Journal: Journal of Molecular Structure - Volumes 735â736, 14 February 2005, Pages 27-37
نویسندگان
Satomi Tanaka, Chihiro Kato, Kazuyuki Horie,