Influence of intermolecular hydrogen bonds on mesomorphism: An integrated experimental and theoretical study

Abstract

Hydrogen bond liquid crystal (HBLC) complexes are isolated from the mesogenic and non-mesogenic compounds. The existence of intermolecular hydrogen bond is confirmed via various experimental results and substantiated by density functional theory (DFT) calculations. Nematic and induced smectic phases along with their corresponding textural sequences are observed along with the enthalpy values using POM and DSC. DFT calculations are employed to understand the molecular geometry of 1,3-PDA + nOBA(1:2) HBLC complexes. HOMO–LUMO explains the charge transfer behavior and the electronic stability of the molecules, which justifies the experimental band gap energy via UV–Vis spectroscopy. The global reactive parameters (GRP) describe the stability and reactivity of the molecules, whereas molecular electrostatic potential (MEP) emphasizes the reactive regions in the HBLC complexes. The interaction region indicator (IRI) and Independent Gradient Model based on Hirshfeld partition (IGMH) are used to visualize and confirm the H-bond and van der Waals interactions in the supramolecular HBLC system.