Antiproliferative activities of trithiolato-bridged dinuclear arene osmium complexes

•Synthesis of dinuclear arene osmium complexes bridged by thiolato ligands.•The single-crystal X-ray structure analysis of a derivative is presented.•The antiproliferative activity of the complexes has been evaluated in vitro.•Highly active complexes on cancerous cells.

Trithiolato-bridged arene osmium complexes of the general formula [(p-cymene)2Os2(μ-SR)3]+ (R = C6H5, [1]+; C6H4-p-Me, [2]+; C6H4-p-OMe, [3]+; C6H4-p-Pri, [4]+; C6H4-p-But, [5]+; CH2C6H5, [6]+; CH2CH2C6H5, [7]+; CH2C6H4-p-But, [8]+) were synthesized in ethanol by reacting the p-cymene osmium dimer [(p-cymene)2Os2(μ-Cl)2Cl2] with the corresponding thiol (RSH). The complexes were isolated as their chloride salts, and fully characterized by spectroscopic methods. The single-crystal X-ray structure analysis of the salt [6]Cl is also presented. These osmium complexes were found to be highly cytotoxic towards several cancerous cell lines (A2780, A549, B16F10, HeLa) with IC50 values comparable or even better to those found for doxorubicin.

Graphical abstractTrithiolato-bridged p-cymene osmium complexes were synthesized and characterized. The antiproliferative activity of all complexes has been established using cancerous and noncancerous cell lines. All complexes were highly active with IC50 values reaching the nanomolar range.Figure optionsDownload full-size imageDownload as PowerPoint slide