New mononuclear diorganotin(IV) dithiocarboxylates: synthesis, characterization and study of their cytotoxic activities

Since organotin complexes have been reported to show fewer side effects relative to other heavy metal anticancer compounds, in the present study we report for the first time four novel organotin(IV) derivatives with the general formula R2SnL2, where R=methyl (1), n-butyl (2), phenyl (3), benzyl (4) and L=morpholine-1-carbodithioate (MCDT). The newly synthesized ligand was monodentate or bidentate, coordinating through a sulfur atom. The complexes were synthesized by directly mixing, refluxing and stirring the ligand, with diorganotin(IV) dichlorides in a suitable solvent. The complexes were found to be pure and their solid and solution phase structural configuration was investigated by FT-IR, multinuclear NMR (H-1, C-13, Sn-119) and mass spectrometry. Complex 2 was also studied for its thermal decomposition by thermogravimetry and differential thermal analysis. The results obtained on the basis of these techniques are in full concurrence with the proposed 1:2 (Sn:L) stoichiometry. The cytotoxic activity of the MCDT and diorganotin(IV) complexes (14) was tested against tumor cell lines human cervix carcinoma HeLa and human myelogenous leukemia K562 and normal immunocompetent cells: peripheral blood mononuclear cells PBMC. Results of bioassay demonstrated that organotin derivatives were in general more active than the anticancer drug cisplatin. Copyright (c) 2012 John Wiley & Sons, Ltd.