Synthesis, Characterization, Theoretical Studies and BSA Binding Of Co(II), Ni(II) and Cu(II) Schiff Base Complexes

Complexes of Co(II), Ni(II), and Cu(II) complexes have been synthesized with biologically active Schiff base ligand L. The structure of ligand L and metal complexes were established by using various spectroscopic studies. On the basis of various spectroscopic studies, octahedral geometry of Co(II) complexes, tetrahedral geometry of Ni(II) complex, and square planar geometry of Cu(II) were established. Molar conductance in dimethylformaide solvent found in the range of 7.5–9.8 Ω⁻¹ cm² mol⁻¹ suggesting the non-electrolyte behaviour of metal complexes. The value of nephelauxetic parameter (β) lies in the range of 0.254–0.586 which indicates the covalent character in metal ligand sigma bond. The dipole moment, chemical hardness, and chemical softness of L and its metal complexes were studied using DFT. Ligand L and metal complexes were screened against two gram’s positive bacterial species Staphylococcus aureus, Streptococcus pyogenes and two gram’s negative bacterial species Escherichia coli and Klebsiella pneumonia. Antibacterial activity results revealed that all metal complexes showed better activity than the free ligand and complex 2 showed better activity than other complexes. The K_{b b} values for complex 2 is 8.1545 × 10⁵,which is greater than complex 3 and 4. It’s indicated that there is strong interaction between the BSA and complex 2. In molecular docking studies, complex 2 has returned lower docking energy than other complexes. It means theoretical studies have good coorelation with experimental results.