Cyclopentadienyltin(IV) derivatives: Synthesis, characterization and study of their cytotoxic activities

Abstract

The organotin compounds, [SnPh 3(C 5H 4R)] (R = Bu t ( 1), CMe 2(CH 2CH 2CH CH 2) ( 2)) and [SnPh 3(C 5Me 4R)] (R = H ( 3), SiMe 3 ( 4)), were prepared by the reaction of SnPh 3Cl with the lithium derivative of the corresponding cyclopentadiene. 1– 4 have been characterized by multinuclear NMR spectroscopy ( 1H, 13C{ 1H} and 119Sn{ 1H}). In addition, the molecular structures of 1, 2 and 4 were determined by single-crystal X-ray diffraction studies. The cytotoxic activity of the organotin(IV) complexes ( 1– 4) was tested against human tumour cell lines 8505C anaplastic thyroid cancer, A253 head and neck tumour, A549 lung carcinoma, A2780 ovarian cancer, DLD-1 colon carcinoma. Compounds 1– 4 present higher activities than cisplatin in all the studied cells. The highest sensitivity of the synthesized tin(IV) complexes was observed against A2780 ovarian cancer and DLD-1 colon carcinoma. Complex 3 presents the highest cytotoxic activity of all the studied complexes in all the cancer cells, with IC 50 values from 0.037 to 0.085 μM, however, its trimethylsilyl-substituted analogue ( 4), showed the lowest activity against all the studied cells with IC 50 values from 0.163 to 0.351 μM. Complexes 1 and 2 presented very similar activities on all the cancer cells (IC 50 values from 0.044 to 0.119 μM).