Synthesis and characterization of a mononuclear nickel(II) complex with N,O-donor ligand: Its DNA/HSA protein binding properties and tumor suppressive function

Abstract

A mononuclear Ni(II) complex, ([Ni(HL)2]Cl2•H2O) (Complex 1), where HL = 1-((2-piperidin-1-yl)ethylimino)methyl)naphthalene-2-ol has been synthesized under mild conditions. It has been characterized by elemental analysis, cyclic voltammetry, FT-IR, UV-vis, fluorescence and mass spectral analyses. Square planar geometry of the mononuclear complex has been confirmed by single crystal X-ray diffraction analysis. Complex 1 interacts with CT DNA with a binding constant of 3.6 × 103 M‒1 which suggests electrostatic interaction between the complex and DNA. The metal complex cleaves plasmid DNA efficiently in the presence of H2O2. On the other hand, complex 1 binds with the carrier protein, HSA, quite efficiently with a binding constant value of 7.16 × 105 M‒1. Cytotoxicity of the complex has been checked with lung carcinoma (A549) and normal lung fibroblast cell lines (WI-38). From MTT assay, it has seen that the complex could inhibit the cell proliferation. Western blot analysis suggests that nickel complex is a tumor suppressor.