Preparation of a dimer from self-complementary of cobalt(III) complex with dissymmetric compartmental ligand and study of the interaction of the complex with DNA and BSA

Abstract

Synthesis of [Co(L)(H₂O)(HOCN(CH₃)₂)](ClO₄) (where L denotes N,N′-bis(3-methoxysalicylidene)-1,2-diaminopropane) was reported. The complex was characterized by ¹H NMR, elemental analysis, IR and UV–vis spectroscopy and the structural features have been solved by X-ray crystallography. The crystal structure analysis showed that the arrangement around cobalt atom is octahedral with two imine nitrogen atoms (N1 and N2) and two oxygen atoms of hydroxyl groups (O2 and O3) at equatorial positions and an aqua ligand and a DMF ligand at the axial positions. The hydrogen-bonding interactions between coordinated H₂O and phenoxo/methoxy oxygens connect the complex molecules in dimers. Interaction of the complex with FS-DNA and protein (BSA) was explored by fluorescence and absorption spectroscopy, viscosity measurements, circular dichroism (CD), cyclic voltammetry (CV) and agarose gel electrophoresis. According to the K_b value about 10³, the complex is moderately bound to DNA. The complex interacts with protein (BSA) by both static and dynamic quenching. According to cleavage experiment, the complex destroys annular DNA and causes double strand break. Molecular docking was done to achieve detailed binding information of the complex to DNA and BSA. Moreover, cytotoxic activity was evaluated by MTT assay. The complex has low toxicity against the MCF-7 and LNCaP cancer cells.

Graphical Abstract

Keywords:

• O-vanillin
• X-ray crystallography
• DNA and BSA binding
• cytotoxicity
• docking

Additional information

Funding

We are grateful to the Shiraz University Research Council for its financial support. The crystallographic part was supported by the project 18-10504S of the Czech Science Foundation using instruments of the ASTRA lab established within the Operation program Prague Competitiveness – project CZ.2.16/3.1.00/24510.