Bimetallic phenylene-bridged Cp/amide titanium complexes and their olefin polymerization.

Bimetallic dichlorotitanium complexes, {2,6-[eta(5)-2,5-Me2C5H2](2)-4-R-C6H2N-microN}{Ti(IV)Cl2}2 (, R=Me; , R=F) and 4,4'-A[{2-(eta(5)-2,3,5-Me3C5H)C6H3NC6H11-kappaN}Ti(IV)Cl2]2 (, A=CH2; , A=O; , A=ortho-C6H4) are prepared via a key step of the Suzuki-coupling reaction of 2-dihydroxyboryl-3-methyl-2-cyclopenten-1-one () with dibromo-compounds. The solid state structure of was determined by X-ray crystallography. Complexes and are not active for ethylene/1-hexene copolymerization. Meanwhile, the complexes are highly active and their activities are higher than that of the mononuclear analogue, {2-(eta(5)-2,3,5-Me3C5H)C6H3NC6H11-kappaN}Ti(IV)Cl2 (). The molecular weights of the polymers obtained with the bimetallic complexes are higher than that of the polymer obtained using . Slightly higher contents of long-chain-branching are observed for the copolymers obtained using the bimetallic system.