Synthesis and characterization of Pd(II) antitumor complex, DFT calculation and DNA/BSA binding insight through the combined experimental and theoretical aspects

Abstract

A novel palladium(II) complex, [Pd(bpy)(acac)]NO3 (where bpy and acac are 2,2′-bipyridine and acetylacetonato), has been synthesized and fully characterized through 1H NMR, UV-Vis and FT-IR spectra, conductivity measurement and elemental analysis. Geometry optimization using DFT calculation demonstrated that a square-planar geometry is built around Pd(II) atom. The MEP and FMO analysis were also applied. Partition coefficient evaluation was conducted to determine the lipophilicity of the compound which follows the order complex > cisplatin. The antitumor activity of the complex has been evaluated on K562 cancer cells by MTT method, which exhibited an appropriate activity in compare to cisplatin. The interaction of [Pd(bpy)(acac)]NO3 towards biomolecules (CT-DNA and BSA) was investigated through in-detail fluorescence, UV–Vis and other techniques. The findings of fluorescence titration demonstrated that the Pd(II) complex binds to CT-DNA via hydrophobic and with BSA through van der Waals forces and hydrogen bond. UV–Vis experiment revealed a reduction in the absorption spectra of biomolecules in presence of the complex. The binding affinity was further endorsed for CT-DNA utilizing viscosity measurement and gel electrophoresis and for BSA via CD spectroscopy and FRET calculation. In addition, molecular docking supports the findings of experiments and indicates that the Pd(II) complex appears to be situated at DNA intercalation position and BSA Sudlow's site I. All results have shown that this compound may be a useful potential antitumor candidate for further medical purposes.