A novel alkenyl-substituted ansa-zirconocene complex with dual application as olefin polymerization catalyst and anticancer drug

Abstract The alkenyl substituted fulvene compound, (C 5 H 4 ) CMe(CH 2 CH 2 CH CMe 2 ) ( 1 ), reacts with one equivalent of LiMe to give the lithium derivative Li{C 5 H 4 (CMe 2 CH 2 CH 2 CH CMe 2 )} ( 2 ). The reaction of 2 with Me 2 Si(C 5 Me 4 H)Cl gave the ansa -ligand precursor Me 2 Si(C 5 Me 4 H)(C 5 H 4 (CMe 2 CH 2 CH 2 CH CMe 2 )) ( 3 ), which after the subsequent reaction with 2 equivalents of LiBu n yielded the dilithium salt Li 2 {Me 2 Si(C 5 Me 4 )(C 5 H 3 (CMe 2 CH 2 CH 2 CH CMe 2 ))} ( 4 ). The alkenyl-substituted zirconocene complex [Zr{Me 2 Si(η 5 -C 5 Me 4 )(η 5 -C 5 H 3 (CMe 2 CH 2 CH 2 CH CMe 2 ))}Cl 2 ] ( 5 ) was synthesized by the equimolar reaction of 4 and ZrCl 4 . 5 was characterized by spectroscopic methods and by single crystal X-ray diffraction studies. The zirconocene compound 5 has been tested as a catalyst in the polymerization of ethylene at different temperatures and Al:Zr ratios, and also in the co-polymerization of ethylene and 1-octene, observing modest co-monomer incorporations. In addition, the cytotoxic activity of 5 was tested against tumour cell lines 8505C anaplastic thyroid cancer, A253 head and neck tumour, A549 lung carcinoma, A2780 ovarian cancer and DLD-1 colon carcinoma. Complex 5 showed the best cytotoxic activity on A2780 ovarian cancer (IC 50 value of 36.8 ± 5.9 μM). This represents the highest reported cytotoxic activity of a zirconocene complex on A2780 ovarian cancer. In addition, the cytotoxic activities of 5 , have been compared with those obtained using cisplatin.