Synthesis, crystal structure and interaction of L-valine Schiff base divanadium(V) complex containing a V2O3 core with DNA and BSA

A divanadium(V) complex, [V2O3(o-van-val)(2)] (o-van-val = Schiff base derived from o-vanillin and L-valine), has been synthesized and structurally characterized. The crystal structure shows that both of the vanadium centers in the complex have a distorted octahedral coordination environment composed of tridentate Schiff base ligand. A V2O3 core in molecular structure adopts intermediate between cis and trans configuration with the O1=V1 center dot center dot center dot V1A=O1A torsion angle 115.22 (28)degrees and the V1 center dot center dot center dot V1A distance 3.455 angstrom. The binding properties of the complex with calf thymus DNA (CT-DNA) have been investigated by UV-vis absorption, fluorescence, CD spectra and viscosity measurement. The results indicate that the complex binds to CT-DNA in non-classical intercalative mode. Meanwhile, the interaction of the complex with bovine serum albumin (BSA) has been studied by UV-vis absorption, fluorescence and CD spectra. Results indicated that the complex can markedly quench the intrinsic fluorescence of BSA via a static quenching process, and cause its conformational change. The calculated apparent binding constant K-b was 1.05 x 10(6) M-1 and the binding site number n was 1.18. (C) 2013 Elsevier B.V. All rights reserved.