Synthesis, structural characterization, in vitro cytotoxicities, DNA-binding and BSA interaction of diorganotin (IV) complexes derived from hydrazone Schiff base

Five diorganotin(IV) complexes of benzoylformic acid 3-hydroxy-2-naphthoyl hydrazone, [R2SnLY]2 (L = 3-HO-C10H6CON2C(C6H5)CO2) with Y = H2O, R = CH3 (1), Y = EtOH, R = Ph (3), Y = EtOH, R = o-Cl-Bz (4), Y = EtOH, R = o-F-Bz (5), and [R2SnLY] with Y = EtOH, R = n-Bu (2) were prepared, which were structurally characterized by X-ray crystallography, elemental, IR and NMR (1H and 13C ) spectroscopy. Structural analysis reveal that the ligand presents as tridentate ligand with ONO donors and coordinates to the tin center in an enolic form. Compound 2 is a monomer while the other compounds are weakly bridged dimers with weak Sn⋯O interactions. In vitro cytotoxicities of compounds 1, 3 and the ligand were determined to explore their potential anticancer activities. DNA-binding properties of 1 and 3 with calf thymus DNA (ct-DNA) were investigated by fluorescence quenching method with ethidium bromide (abbr. EB)-DNA system. Furthermore, the protein fluorescence quenching studies reveal that there are strong binding interactions between compounds 1, 3 and bovine serum albumins (BSA). Synchronous fluorescence spectra show that both the tryptophan and tyrosine residues in BSA are affected by the two compounds.