Zinc Carboxylate Liquid Crystals : Solid State Structures and Thermotropic Phase Transition Behaviour of a Homologous Series of Zinc(II) n-Alkanoates

Mesogenic behaviour of metal carboxylates has been an important area of study, since many of them exhibit smectic C mesophases, and as such, have potential use in ferroelectric liquid crystal displays (LCDs). As a result, the study of thermal phase transitions of various mono- and divalent metal carboxylates has been a focus. Of keen interest are zinc(II) n-alkanoates, since there remain some unanswered questions regarding the characteristics and dynamics of their phase behaviour. As with materials in the solid state, there is a correlation between structural features and properties, and for compounds that display thermotropic mesomorphism, there must be a firm understanding of the relationship between structure, intermolecular interactions, thermophysical properties and phase behaviour. In this study, the thermal behaviour of a homologous series of zinc(II) n-alkanoates are investigated by differential scanning calorimetry and hot-stage polarized light microscopy. From the data, an attempt is made to correlate the thermal behaviour of the compounds with their solid state structures studied using X-ray crystallography and diffraction, IR spectroscopy and molecular calculations.