LAUSR

Abstract In this study, Sulfadiazine-Ortho-Vanillin Schiff base namely (E)-4-((2-hydroxy-3-methoxybenzylidene)amino) N-(pyrimidin-2-yl)benzene-sulfonamide (BS) was synthesized. Chemical characterization and computational studies using different techniques like XRD, FT-IR, UV–Vis, NBO, FMO, and MEP have been employed. Density functional theory (DFT) calculations have been performed at M06-2X/6-311 + G(d,p) level of theory to obtain optimized geometry and vibrational wave numbers for (E)-4-((2-hydroxy-3-methoxybenzylidene)amino) N-(pyrimidin-2-yl)benzene-sulfonamide (BS). The DFT optimized geometry supports the experimental XRD parameters. Frontier molecular orbital (FMO) energies and molecular electrostatic potential (MEP) surfaces have been executed at M06-2X/6-311 + G(d,p) level of theory. NBO analysis has been carried out at M06-2X/6-311 + G(d,p) level which not only discovered the hyper conjugative interactions and stability in title molecule but also reconfirmed the existence of N H⋯N hydrogen bonds between the dimer. The findings of small EHOMO–ELUMO gap shows less hardness and larger softness values which suggested the bioactiveness of the title molecule. Finally, the effect of solvent on nonlinear optical (NLO) properties has been executed using M06-2X level of theory and 6-311 + G (d,p) basis set. The solvent polarity enhanced the NLO response from 3.62 × 10−30 esu to 4.66 × 10−30 esu indicating the considerable NLO character hence in general may have potential applications in the development of non-linear optical materials.