An experimental and theoretical study on the interaction of DNA and BSA with novel Ni 2+ , Cu 2+ and VO 2+ complexes derived from vanillin bidentate Schiff base ligand.

In this investigation, the structure of bidentate N,N-Schiff base ligand of vanillin, (E)-4-(((2-amino-5-nitrophenyl)imino)methyl)-2-methoxyphenol (HL) was determined by single crystal X-ray diffraction. The interaction of new [CuL2 ], [NiL2 ] and [VOL2 ] complexes with DNA and BSA was explored through UV-Vis and fluorescence spectroscopy. The electronic spectra changes displayed an isosbestic point for the complexes upon titration with DNA. The Kb values for the complexes [CuL2 ], [NiL2 ] and [VOL2 ] were 2.4×105 , 1.9×105 and 4.2×104 , respectively. [CuL2 ] complex was bound more toughly than [NiL2 ] and [VOL2 ] complexes. These complexes had a significant interaction with Bovine Serum Albumin (BSA) and the results demonstrated that the quenching mechanism was a static procedure. Also, the complexes interacted with BSA by more than one binding site (n>1). Finally, the theoretical studies were performed using the docking method to calculate the binding constants and recognize the binding site of the DNA and BSA with the complexes. The ligand and complexes including Ni2+ , Cu2+ and VO2+ ions were colonized by fungal growth.