Dipole moment and solvatochromism of benzoic acid liquid crystals: Tuning the dipole moment and molecular orbital energies by substituted Au under external electric field

The optical absorption and steady-state fluorescence spectra of 4-heptyloxybenzoic acid (4hoba), 4-octyloxybenzoic acid (400ba) and 4-nonyloxybenzoic acid (4noba) liquid crystals have been measured in a series of different polarity organic solvents. The ground state (mu(g)) and excited state (mu(e)) dipole moments of the monomeric and dimeric 4-alkyloxybenzoic acid liquid crystals have been obtained by means of different solvatochromic shift methods. HOMO-LUMO gaps (HLG) and dipole moments have been tuned by applying external electric (EF) field on monomer, dimer and Au substituted monomer and dimer liquid crystal structures. By applying external electric field, Au substituted monomer liquid crystals display semiconductor character, while Au substituted dimer liquid crystals gain metallic character under E = 0.04 V/angstrom. Eventuated specific and non-specific interactions between solvent and solute in solvent medium have been expounded by using LSER (Linear Solvation Energy Relationships). (C) 2017 Elsevier B.V. All rights reserved.