苯乙烯基吡啶类液晶化合物的分子结构及相变过程的光谱研究

The Molecular Structure and the Arrangement Changes of Stilbazoles in the Phase Transition Process Studied by Temperature-variable FTIR Spectroscopy

通过苯乙烯基吡啶和不同脂肪羧酸间的氢键作用构成液晶的方法具有合成路线灵活、简便、易于变化的特点。本文通过变温红外光谱对做为质子受体的苯乙烯基吡啶类液晶化合物的分子结构和相变过程中分子排列的变化进行了研究。结果表明在液晶分子中象羰基这样的偶极矩较大的极性基团 ,对分子所处的相态分子间的相互排列比较敏感。在红外光谱中羰基伸缩振动的变化可以看作是液晶分子相态转变的标志。

Hydrogen bonding is one of the principal intermolecular forces to enable the construction of supramolecular structures.By choosing an appropriate proton acceptor and a proton donor,stable intermolecular hydrogen bonds can form and affect or change the phase behavior of the donor and acceptor.We have obtained two intermolecular hydrogen bonded liquid crystals using the stilbazoles as the proton acceptor.In this paper we will research the molecular structure and the arrangement changes during the phase transition process of the stilbazoles by temperature variable FTIR spectroscopy.The results show that the number of the gauche conformation is increasing as the temperature increasing.When it is coming to the isotropic phase,the alkyl chain is in disorder.The frequency shift of carbonyl stretching bands has been found to be sensitive to the change of molecular conformation,inter and intramolecular interactions.