Synthesis, characterization and antitumor properties of titanocene derivatives with thiophene containing ligands

The titanocene complexes [TiCp2(Cl)R] (1), [TiCp2(Cl)SR] (2), [TiCp2(SR)2] (3) with R = benzothienyl (BT) A and dibenzothienyl (DBT) B, were synthesized and the molecular structures of [TiCp2(Cl)DBT] (1B) and [TiCp2(Cl)SDBT] (2B) confirmed by single crystal X-ray diffraction studies. The dibenzothiophene rings are planar and for 1B in the plane of the titanium and chloro ligand. The chloro ligand is in a trans position to the sulfur atom with respect to the titanium–carbon bond. The complexes were studied for their electronic and structural features and preliminary tests were conducted for their tumor inhibiting properties against HeLa and COLO 320M tumor cell lines. These antitumor activities were compared against those observed for titanocene dichloride (S-01) under similar conditions and the highest antitumor activity was recorded for 2B.