Synthesis, Spectroscopic, SC-XRD/DFT and Nonlinear Optical Response of New Halogenated Schiff Base Ligand and its Square Planar Complexes

This study details the synthesis and characterization analysis of a of new halogenated Schiff base ligand (E)-4-((5-bromo-2-hydroxybenzyldene) amino) butanoic acid (HL) and its Square Planar trans-L-2 Cu(II) complex. Characterization was performed using a suite of spectroscopic techniques, including 1H and 13C NMR, FT-IR, Raman, and UV-Vis spectroscopy, with thorough explanations and discussions of the spectral data. The structure of ligand and its complex CuL2 were elucidated through single-crystal X-ray crystallography. Additionally, the study extended to the computational domain, where the structural optimization, reactivity descriptors, and linear optical properties, as well as the static and dynamic first and second hyperpolarizabilities of HL, Cr(II)L-2, Mn(II)L-2, Co(II)L-2 and Cu(II)L-2 were investigated using DFT and TD-DFT calculation. Our results indicate that the second hyperpolarizability escalates as the atomic number of the transition metal increases. Moreover, it is inferred that the ligand examined holds the potential to be a superior material for second-order nonlinear optical applications.