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N. A. Chyumaevskiy¹, N. S. Kucherepa¹, A. N. Isaev², S. A. Syrbu³, N. A. Minaeva¹, A. A. Syrbu³

Author affiliations
¹N. S. Kurnakov Institute of the General and Inorganic Chemistry of the RAS.
119991 Moscow, Lenin Av., 31. Е-mail: chumaevskii@igic.ras.ru
²N. D. Zelinsky Institute of Organic Chemistry of the RAS
119991 Moscow, Leninsky prospect, 47. 
E-mail: isaevaln@ioc.ac.ru
³Ivanovo State University
153025 Ivanovo, Ermak Str., 39. 
E-mail: syrbue@yandex.ru

Abstract
Dynamical character of thermotropic liquid crystals – p-n-alkyloxy-p'-cyanobi-phenyls structure was investigated by infrared spectroscopy method. Quantum – chemical calculations of infrared spectrum, geometrical and electronic cyanobiphenyls molecules structure for different angle α between phenyl rings planes volumes were operated by B3LYP/6-31+G^** method. Shown, that twist-conformation with angle α≈37^o is the most stable molecule conformation. In accord with the calculations the increase of angle leads to the 5 sm^-1 increase in –CN-group α-frequency fluctuations, but infrared region intensity decreases two times. Aliphatic chain lengthening does not bring any marked difference of molecule central part geometric structure, and calculated –CN-group frequency fluctuations. Shown, that cyanobiphenyl molecules conformation conversions, particularly in the alkyloxy-radicals part, play a determinate role in liquid crystals mesogens.

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