Organotin(IV) complexes derived from Schiff base N’-[(1E)-(2-hydroxy-3-methoxyphenyl)methylidene]pyridine-3-carbohydrazone: Synthesis, in vitro cytotoxicities and DNA/BSA interaction

Abstract Five organotin(IV) hydrazone compounds have been synthesized from N’-[(1E)-(2-hydroxyl-3-methoxyphenyl)methylidene]pyridine-3-carbohydrazone and the corresponding organotin(IV). Solid state structures of five complexes were determined by elemental analysis, IR, NMR spectroscopy and for 1 , 2 , 3, 4 and 5 single crystal X-ray diffraction analysis. For compounds 4 and 5 , structural analysis shows that each complex is a monomer with the tin atom five-coordinated in a distorted trigonal bipyramid chelating by the Schiff base ligand in an enolic tridentate fashion. Fascinatingly, in compounds 1, 2 and 3 , structural analysis of them shows that each complex is a centrosymmetric trimers, in which the central Sn atom adopts six-coordinated geometry and the other Sn atom adopts five-coordinated geometry. In vitro cytotoxicities of five compounds on three human drug resistant tumor cells lines (A549, HeLa and MCF-7) were assessed by MTT assay. The interaction of the complexes with calf thymus DNA (CT-DNA) has been explored by absorption titration method, which revealed that complexes interact with CT-DNA through groove-binding and partial intercalation of the extended planar ligand with the DNA base stack. Furthermore, the protein fluorescence quenching studies reveal that there are strong binding interactions between compounds and bovine serum albumins (BSA). Studies reveal that di- n -butyltin(IV) complexes 2 and 4 with significant antiproliferative effects in the cells show stronger DNA/BSA interaction than the other complexes.