Synthesis, crystal structure, Hirshfeld surface analysis, DNA binding, optical and nonlinear optical properties of Schiff bases derived from o-aminophenol

Abstract

The current work focuses on the synthesis of the two new Schiff base ligands derived from o-aminophenol named 2-[(E)-(3-chlorophenyl)methylidene]amino-phenol (2AP3Cl) and 4-Chloro-2-(E)-[(2-hydroxyphenyl)iminio]methyl-phenolate (2AP5Cl). The synthesized Schiff bases were characterized by different Spectro analytical techniques like CHN, FT-IR, and NMR (1H and 13C) analysis. Moreover, a single crystal X-ray diffraction (SC-XRD) study was carried out for both compounds, which inferred that 2AP3Cl and 2AP5Cl adopted enol and keto tautomeric forms, respectively. The supramolecular assembly with respect to strong and comparatively weak non-covalent interactions was explored by Hirshfeld surface analysis. The interaction energy between molecular pairs, energy frameworks, and void analysis was performed to further investigate the crystal packing environment. Both compounds were screened for their DNA binding abilities. Moreover, quantum chemical methods were applied to study the electronic structure, linear and nonlinear optical (NLO) polarizabilities of the synthesized Schiff bases. The 2AP3Cl and 2AP5Cl molecules exhibited good NLO hyperpolarizability of 9.62 × 104 and 7.90 × 104 au., respectively. The calculation of molecular electrostatic potentials, 3-D visualization of frontier molecular orbitals, and their orbital gaps were also studied. Overall, reasonably good third-order NLO response properties were calculated, which show a decent potential of synthesized compounds for their potential for NLO applications.