Synthesis, characterization, DFT studies, target prediction, molecular docking, and ADMET properties of the Schiff base 2-[2-[(2-Hydroxyphenyl)methylideneamino]ethyliminomethyl]phenol and its Ni(II) and Co(II) complexes

A Schiff base ligand, 2-[2-[(2-hydroxyphenyl)methylideneamino]ethyliminomethyl]phenol <b>1</b>, and its Ni(II) <b>2</b> and Co(II) <b>3</b> complexes were synthesized and characterized by elemental analysis, FTIR, UV-vis spectroscopy, ESI-MS, magnetic moment, and molar conductance measurements. The data confirmed formation of square planar complexes <i>via</i> ONNO tetradentate coordination. The DFT studies and geometry optimization further supported the proposed structures of the ligand <b>1</b>, and its Ni(II) <b>2</b> and Co(II) <b>3</b> complexes and also predicted that the complexes (<b>2</b>, <b>3</b>) are more reactive to the receptor. Molecular docking studies revealed strong binding affinity of Ni(II) <b>2</b> complex toward the human GABA receptor (PDB ID: 6X3T), a key target in inhibitory neurotransmission predicted by PASS prediction analysis. ADMET and drug-likeness highlighted favorable pharmacokinetic profiles of the synthesized compound, especially for ligand <b>1</b>, suggesting its potential as a neuroactive agent. Moreover, nonlinear optical (NLO) analysis indicated that Ni(II) <b>2</b> and Co(II) <b>3</b> complexes exhibited superior NLO behavior compared to standard urea, pointing to potential optoelectronic applications. Overall, Ni(II) <b>2</b> complex emerges as a promising multifunctional candidate for both neuromedical and NLO material development.