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

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.