Study of the effect of molecular structure and alkyl groups bound with tin(iv) on their cytotoxicity of organotin(iv) 2-phenyl-4-selenazole carboxylates

Abstract

Five organotin(IV) compounds Ph₃SnL (1), (R₂Sn)₄O₂L₄ [R = n-Bu (2), n-Oct (3)], (R₂Sn)₄O₂L₂Cl₂ [R = n-Bu (4), Me (5)], have been synthesized from the reactions of 2-phenyl-4-selenazole carboxylic acid (HL) with the corresponding organotin(IV) oxide or chlorides. These compounds have been characterized by elemental analysis, IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy, and single crystal X-ray diffraction analysis. Structural studies reveal that compound 1 exhibits a mononuclear four-coordinated tetrahedral geometry. Differently, the crystal structures of compounds 2–5 reveal the formation of the tetranuclear species containing a planar Sn₄O₄ core. All compounds were screened for their in vitro cytotoxic activities toward three cancer cell lines (Caco-2, A549, and HCT-116) and one normal rat hepatocyte cell line (BRL). The results indicate that both di-n-butyltin(IV) and triphenyltin(IV) derivatives not only show excellent cytotoxic activities on cisplatin-sensitive lung cancer cell line A549 and but also exhibit good cytotoxicity against cisplatin-insensitive colon cancer cell lines HCT-116 and Caco-2. Whereas, dimethyltin(IV) and di-n-octyltin(IV) complexes exhibit lower or no cytotoxic activity. The structure–activity relationship of the cytotoxicity of the title complexes has also been discussed.