Synthesis, characterization, and mesomorphic investigations of diester-substituted salicylaldimines and their copper (II) complexes

Abstract

A novel homologous series of N-[4-[4′-n-alkoxy)benzoyloxy-2-hydroxybenzylidene)-4-carbethoxy anilines, H2n+1CnOC6H4C(O)OC6H3(OH)C(H)NC6H4COOC2H5 (n = 6, 8, 10, 12, 14, 16) and their copper(II) complexes have been synthesized. All these compounds have been characterized by suitable spectroscopic techniques. The mesomorphic properties of these compounds were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The ligands exhibit wide range of enantiotropic smectic A and nematic phases as confirmed by their typical optical texture under polarizing microscope. The square planar copper(II) complexes of the ligands show only an isotropic phase at higher temperature and no mesogenic nature is observed. DFT calculations have been performed using GAUSSIAN-03 program at B3LYP level to obtain the stable electronic structure of the ligand with decyloxy chain length and its copper(II) complex. © 2016 Taylor and Francis Group, LLC.