C1-bridged fluorenylidene-indenylidene complexes of the type (C13H8-CR2-C9H6-nR′n)ZrCl2 (n = 0, 1, R = Me, Ph, butenyl, R′ = alkyl, alkenyl) as metallocene catalyst precursors for ethylene polymerization

Twenty-three new ansa metallocene complexes of the type (C13H8-CR2-C9H6-nRn')ZrCl2 (38-64) (n = 0, 1; R = Me, Ph, butenyl; R' = alkyl, alkenyl) and the corresponding ligand precursors have been synthesized and characterized. The bonding situation of the pi-ligands to the metal of C-1-bridged complexes in solution was determined by NMR-spectroscopy. All complexes were tested for catalytic ethylene polymerization after activation with methyl aluminoxane (MAO). The substituents R in the bridge and the substituents R' in the 3-position of the indenylidene moiety have a strong influence on the activity of the catalysts and the molecular weight of the formed polymers. The omega-alkenyl substituents R and R' allow self-immobilization of the catalysts during the polymerization.