Synthesis, structural characterization, <i>in vitro</i> cytotoxicities, and BSA interaction of di-organotin(IV) complexes derived from salicylaldehyde nicotinoyl hydrazone

<p>Two organotin(IV) compounds were synthesized from salicylaldehyde nicotinoyl hydrazone and the corresponding dialkyltin(IV) precursor. Their structures were determined by IR, elemental analysis, NMR, and single crystal X-ray diffraction analysis. Compound <b>1</b> exhibits a distorted trigonal bipyramidal geometry around tin, which is coordinated to the Schiff-base ligand in an enolic tridentate fashion. For <b>2</b>, structural analysis reveals that it is a centro-symmetric trimer, in which the central Sn adopts a six-coordinate octahedral geometry and the other two Sn ions adopt five-coordinate trigonal bipyramidal geometry. <i>In vitro</i> cytotoxicities of the compounds against three human cisplatin-resistant tumor cell lines (A549, HeLa, and MCF-7) were assessed by MTT assay. Further, the interaction of <b>1</b> and <b>2</b> with bovine serum albumin (BSA) has been explored by the titration method with fluorescence quenching spectra and synchronous fluorescence spectra. Studies reveal that di-n-butyltin(IV) complex <b>1</b> with significant antiproliferative effects in the cells shows stronger BSA interaction.