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

Abstract A divanadium(V) complex, [V 2 O 3 ( 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 V 2 O 3 core in molecular structure adopts intermediate between cis and trans configuration with the O1 V1⋯V1A O1A torsion angle 115.22 (28)° and the V1⋯V1A distance 3.455 A. 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 × 10 6  M −1 and the binding site number n was 1.18.