Abstract |
Syntheses, crystal structures and biological activities of the diphenoxo-bridged diorgano dinuclear Sn(IV) compounds [Sn(Et)(2)(HL)(H2O)](2) (1) and Sn(n-Bu)(2)( HL)(H2O)](2) (2) derived from the Schiff base 2-1(2,3-dihydroxyphenyl)methylideneamino]benzenesulfonic acid trihydrate (H3L center dot 3H(2)O) are described. The monoprotonated form (HL2-) of the Schiff base behaves as O,O -bidentate ligand, chelating the metal by the two phenoxo oxygen atoms. The hexacoordinated metal centres in 1 and 2 are bridged by a phenoxo oxygen and the remaining coordination positions are fulfilled by the other phenoxo oxygen, two organic groups (ethyl for 1 and n-butyl for 2) and a water molecule. A two dimensional zigzag sheet in 1 and three dimensional polymeric networks in H3L center dot 3H(2)O and 2 are stabilized by a number of non-covalent, H-bonding and pi...pi stacking interactions. The DNA binding activities of these complexes have been studied by UV-vis and fluorescence spectroscopies. Their antiproliferative efficacies have been evaluated on A-549, HeLa and MDA-MB-231 cancer cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MIT) assay. IC50 values (1.35 +/- 023, 2.43 +/- 0.54 and 1.74 +/- 0.04 mu M for 2) are indicative of a substantial cytotoxicity of 2, mainly towards the A-549 lung cancer cell line. The greater antiproliferative efficacy of 2 has further been studied by fluorescence activated cell sorting (FACS) and nuclear morphology by Hoechst/propidium iodide (PI) double staining method. The possible mode of the apoptotic pathway for 2 has been substantiated by the reactive oxygen species (ROS) generation studies. (C) 2016 Elsevier Inc. All rights reserved. |