In-silico investigation of optical, thermal and electronic properties for 4-n-alkoxy benzoic acid series (nOBA; n = 1–8)

Abstract

The homologous series of 4-n-alkoxy benzoic acid (nOBA) has been chosen to study the variation of electro-optical properties, global reactivity descriptors and thermal properties with the homologous number using density functional based calculations at B3LYP/6-31G(d,p) level. The first two homologues of nOBA (n = 1 and 2) are non-mesogenic compounds. This homologous series exhibits nematic behaviour for n = 3 to 6 while smectic behaviour for n = 7, 8 and above. We have calculated electro-optical parameters such as dipole moment, polarizability, anisotropy in polarizability, molar refractivity, which exhibit no odd-even effect but linear dependence on the homologous number. Furthermore, the global reactivity parameters such as ionization potential, electron affinity, electronegativity, global hardness and softness are almost constant, independent on the homologous number of nOBA series. Thermal parameters such as enthalpy, Gibbs' free energy and entropy of nOBA series are in accordance with the experimental findings reported in the literature. The results may offer better insights into the properties of homologues of nOBA system at the molecular level.