2,2′-Bipyridyl-1,1′-dioxide based bismuth(iii) bromide hybrids: studies on crystal structure and luminescence

The choice of organic solvents could induce inorganic–organic bromobismuthate hybrids with diverse metal–ligand linking modes.

Sulfonated Schiff base Sn(IV) complexes as potential anticancer agents

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-[(2,3-dihydroxyphenyl)methylideneamino]benzenesulfonic acid trihydrate (H₃L·3H₂O) are described. The monoprotonated form (HL^2-) 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·3H₂O and 2 are stabilized by a number of non-covalent, H-bonding and π⋯π 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 (MTT) assay. IC₅₀ values (1.35±0.23, 2.43±0.54 and 1.74±0.04μM for 2) are indicative of a substantial cytotoxicity of 2, mainly towards the A-549 lung cancer cell line. The greater antiproliferative efficacy of 2has 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 2has been substantiated by the reactive oxygen species (ROS) generation studies.