Synthesis and liquid crystalline properties of hydrazide derivatives: hydrogen bonding, molecular dipole, and smectic structures

Abstract

2008) Synthesis and liquid crystalline properties of hydrazide derivatives: hydrogen bonding, molecular dipole, and smectic structures, Liquid Crystals, 35:3, 333-338, A series of dissymmetric hydrazide derivatives with amino terminal group, N-(4-alkoxybenzoyl)-N9-(49-aminobenzoyl) hydrazine (Cn-NH 2 , n indicates the number of carbon atoms), were designed and synthesised, and their liquid crystalline properties were investigated by means of differential scanning calorimetry, polarised optical microscopy, and wide-angle X-ray diffraction. It was found that these materials showed a SmA d phase, and intermolecular hydrogen bonding was confirmed as the driving force. Moreover, these results were further compared with those of their parent compounds, N-(4-alkoxybenzoyl)-N9-(49-nitrobenzoyl) hydrazine (Cn-NO 2 ) and the dimers, a, v-bis [N-(4-nitrobenzoyl)-N9-(benzoyl-49-oxy) hydrazine] alkane (Nn), and the effect of hydrogen bonding, dipole-dipole interactions on the smectic structures is discussed.