Insights into the electronic structure and interaction energies of 4-ethoxy-N-(4-ethoxy-2-hydoxybenzylidene)benzohydrazide

Abstract

The molecule 4-ethoxy-N-(4-ethoxy-2-hydroxybenzylidene)benzohydrazide (4EHB) is characterized by a rigid aroylhydrazone core, acting as a mesogenic unit, and a flexible chain at its terminal end. The aroylhydrazone core comprises two aromatic rings linked by connecting groups, resulting in moderate size and elongation of the molecule. Variations in the positions and orientations of elongated molecules give rise to different mesogenic phases such as Nematic, Smectic, and Hexatic Smectic. The mesogenic behavior of aroylhydrazone-based materials is governed by various non-covalent interactions. In this study, molecular geometry optimization, analysis of HOMO-LUMO orbitals, and MEP surfaces of individual and pairs of 4EHB molecules were conducted using the Density functional B3LYP technique with the basis set 6-31G**. Intermolecular interaction energies between pairs of 4EHB molecules are evaluated using the technique M06-2X/6-311G** in stacking, terminal, and side-to-side (in-plane) configurations. Basis set superposition error (BSSE) is corrected using counterpoise method and interaction energy(I.E.) is decomposed in different components using SAPT0 method at level 6-311G**, which provided insights into the mesogenic behavior of the system.