Influence of alkoxy chain length on the electro-optical, nonlinear optical and electronic properties of 4-(4-alkoxybenzylideneamino) benzoic acid liquid crystal homologous series: a DFT study

The present work examines electro-optical, nonlinear optical, electronic and chemical reactivity properties of 4-(4-alkoxybenzylideneamino) benzoic acid homologous series using density functional theory techniques. Long-range corrected Becke–Lee–Yang–Parr functional and Becke three-parameter Lee–Yang–Parr functional, with 6-311+G(d,p) basis set are employed to evaluate the influence of alkoxy chain on molecular properties. Comparative analysis is performed to identify most suitable functional describing electro-optical response, nonlinear optical behavior, electronic structure, and chemical reactivity of the homologues. Results show that electro-optical properties, nonlinear optical responses, and optical anisotropy increase systematically with chain length. In contrast, energies of highest occupied and lowest unoccupied molecular orbitals, energy gap, and global reactivity descriptors remain nearly constant throughout series. This behavior indicates that these compounds preserve their intrinsic electronic structure and chemical stability despite chain extension. Overall, long-range corrected functional provides more reliable description of frontier orbital energies and reactivity characteristics than conventional hybrid functional.