Quantitative structure and activity relationship on the biological, nonlinear and the spectroscopic properties of the Schiff base material: 4-chloro-4′bromobenzylidene aniline

The structural and non-linear optical properties of the Schiff base material, 4-chloro-4′bromobenzylidene aniline (CBBA) were analysed using FTIR, FT-Raman, UV and Nuclear Magnetic Resonance spectral techniques together with DFT method and Z-scan technique. Natural Bond Orbital (NBO) analysis method was employed to analyse the intramolecular electronic interactions leading to the stability of the molecule. The complete vibrational assignments were performed based on the scaled quantum mechanical force field procedure. The energies of the frontier orbitals, HOMO–LUMO energy gap and the quantum chemical descriptors such as the electron affinity, ionisation potential, electronegativity, electrophilicity index, global softness, chemical hardness and chemical potential, were calculated in order to quantify the chemical reactivity of the molecule. The non-linear optical (NLO) properties of the CBBA molecule interrelated with the property of 4-bromo-4′chloro benzylidene aniline (BCBA), 4-bromo-4′bromo benzylidene aniline (BBBA), 4-chloro-4′chloro benzylidene aniline (CCBA) and the molecule having hydrogen atom instead of halogen atom (HHBA) was examined. The result provides direct information regarding the relationship between molecular structure and NLO property. Z scan studies performed on the molecule reveal its potential and suitability in optical limiting applications. The molecule was subjected to molecular docking on the active sites of the protein structures of 2B7A, 2E9V, 2OFV and 3E93 to observe binding modes in terms of lowest docking energy.