Synthesis of anti-4-phenoxyphenylaminoglyoxime and its some transition metal complexes: Spectral, DFT, electrochemical and anticancer activity studies

Abstract

anti-4-phenoxyphenylaminoglyoxime (LH2) was synthesized starting from 4-aminodiphenylether and anti-chloroglyoxime in absolute ethanol. Then, mononuclear complexes [Ni(II) and Cu(II)] of LH2 were synthesized with the metal:ligand ratio of 1:2. The LH2 and its complexes [Ni(LH)2 and Cu(LH)2] were characterized by elemental analysis, FT-IR, Raman, UV–vis, thermogravimetric analysis (TGA), 1H NMR, 13C NMR, heteronuclear multiple bond correlation (HMBC) spectroscopy and theoretical DFT studies. Also, redox properties of the ligand and its complexes were investigated by cyclic voltammetry in DMSO solution at room temperature. Conformational space was scanned with molecular mechanic simulations and then the possible stable conformers of LH2 ligand were determined by B3LYP/6–311++G (d,p) level calculations. The Ni(LH)2 and Cu(LH)2 metal complexes were modeled theoretically using B3LYP/LanL2DZ level. The theoretical vibrational frequencies were calculated by using optimization calculation levels. The NMR parameters of LH2 ligand, Cu(LH)2 and Ni(LH)2 metal complexes were calculated at mPW1PW91/6-311 + G (2d,p) level. Theoretically calculated values were compared with the related experimental values. The DFT calculation results have been used to predict and interpret the molecular structures of LH2 ligand and its complexes. The geometry around nickel in Ni(LH)2 and around cupper in Cu(LH)2 complex are almost square planar. In addition, we evaluated the efficacy of LH2 ligand and its Ni(LH)2 and Cu(LH)2 complexes in the breast adenocarcinoma cell line (MCF7). Our data showed that the metal compounds affect positively the cytotoxic activity of the ligand (LH2). The metal complexes, especially Ni(LH)2 complex, exhibited noteworthy biological activity against the viability of MCF7 cells.