Experimental and theoretical (DFT) approaches on novel ternary liquid crystals derived from asymmetric aromatic dicarboxylic acid

Abstract

Novel ternary liquid crystal (TLC) homologues series was designed and prepared from 4-methoxycinnamic acid (4MCA), homophthalic acid (HPA) and 4-n-alkyloxybenzoic acids (nOBA, where n = 6 to 12). The mesogenic behaviour, phase transition temperature, thermal span width and thermal stability factor of TLC (homologues series) were studied by polarising optical microscopy (POM) and differential scanning calorimetry (DSC) techniques. A noteworthy observation is that, TLC induces smectic A (batonnets texture) along with nematic and smectic F phases whereas, the Sm A is not perceived in the individual compounds while compared with the TLC. Further, the existence of smectic phases (Sm A and Sm F) are identified by temperature dependent X-ray diffraction (XRD) analysis. The same are correlated with DSC observations. Density functional theory (DFT) is used to optimize the molecular geometry of TLC. FMO and MEP study explores the molecular environment and quantum chemical behaviour of TLC. NBO, QTAIM and RDG analysis explicate the charge transfer with stabilization energy and non-covalent interactions. Density functional theory (DFT) calculations confirm the possible conformer of TLC.