Synthesis/structural and mesomorphic properties of substituted hydrazide based calamitic molecules

A set of rod-shaped molecules with central hydrazide moiety has been synthesized and characterized using standard spectroscopic techniques. The thermal behaviors of the final compounds were established by the combination of differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and high-temperature powder X-ray method (XRD). The structure and conformation of the molecules were achieved by FTIR, ¹H NMR, ¹³C NMR spectroscopy and DFT calculations. It is found that two compounds are non-liquid crystalline and two compounds are liquid crystalline (LC). The structure property correlations with alkyl chain, connecting position, hydrogen bonding and without hydrogen bonding were established. The studies envisaged that LC properties are induced due to hydrogen bonding and elongation of the molecular length.