Synthesis, structural characterization, DNA binding studies and antitumor properties of tin(II)-oxydiacetate complexes containing α-diimine as auxiliary ligand

Metal directed supra molecular assemblies with interesting topologies have been widely used as models for metallo-enzymes and in development of metallo-pharmaceuticals. Two novel tin(II)-oxydiacetate complexes with α-diimine (1,10-phenanthroline or 2,2′-bipyridine) as auxiliary ligand were synthesized and characterized by elemental analysis, FT-IR, 1H-, 13C- and 119Sn-NMR and single crystal X-ray crystallography. The spectral investigations and X-ray data show that {Sn} is hepta coordinated with pentagonal bipyramidal (pbp) geometry of the complexes. The in vitro binding and cleavage studies using CT DNA by UV–visible, fluorescence and agarose gel electrophoresis techniques revealed that both complexes bind DNA via intercalation. The observed magnitudes of Kb for complexes (1) and (2) are 2.517 × 104 and 5.35 × 103, respectively, which suggest that (1) has strong binding affinity for CT DNA as compared to (2). The complexes were tested for antitumor properties and found highly active at 10−4 M concentration against P388, HL-60 and A-549 cell lines.