反铁电液晶TFMHxPOCBC-D_2中CD_2偏振红外光谱及手性烷基链受阻转动的研究

HINDERED ROTATION OF CHIRAL ALKYL CHAIN IN ANTIFERROELECTRIC LIQUID CRYSTAL TFMHxPOCBC D 2 AS OBSERVED BY POLARIZED IR SPECTROSCOPY OF CD 2 STRETCHING VIBRATION

观测到反铁电液晶分子ＴＦＭＨｘＰＯＣＢＣＤ２（４（ｔｒｉｆｌｕｏｒｏｍｅｔｈｙｌｈｅｘｙ３ｄ２ｃａｒｂｏｎｙｌ）ｐｈｅｎｙｌ４’ｏｃｔｙｌｏｘｙｂｉｐｈｅｎｙｌｃａｂｏｘｙｌａｔｅ）中ＣＤ２的偏振红外光谱中液晶分子的手性烷基链的受阻转动，以及较大的双色吸收特性．应用一个分子模型，进行了偏振红外吸收的模拟计算，与实验结果相比较，得到液晶分子手性烷基链与分子长轴的夹角约为７０°，其受阻方向在液晶分子倾斜方向一侧的半圆内．

Abstract Using a homogeneously aligned cell as a holder for liquid crystols , we have investigated the polarization dependence of FT IR of the stretching of CD 2 in chiral alkyl chain of TFMHxPOBC D 2(4 (trifluoromethylhexy 3 d 2 carbonyl)phenyl 4' octyloxybiphenyl caboxylate) and observed the hindered rotation of the chiral alkyl chain for the first time to our knowledge. Simulation on the IR polarized absorbance leads to an angle of 70° between the chiral alkyl chain and the molecular axis.The biased direction and the tilt direction of molecules are toward the same side.