Bimetallic phenylene-bridged Cp/amide titanium complexes and their olefin polymerization
作者:Sang Hoon Lee、Chun Ji Wu、Ui Gab Joung、Bun Yeoul Lee、Jinil Park
DOI:10.1039/b710017e
日期:——
Bimetallic dichlorotitanium complexes, 2,6-[η5-2,5-Me2C5H2]2-4-R-C6H2N-µN}Ti(IV)Cl2}2 (7, R = Me; 8, R = F) and 4,4′-A[2-(η5-2,3,5-Me3C5H)C6H3NC6H11-κN}Ti(IV)Cl2]2 (18, A = CH2; 19, A = O; 20, A = ortho-C6H4) are prepared via a key step of the Suzuki-coupling reaction of 2-dihydroxyboryl-3-methyl-2-cyclopenten-1-one (1) with dibromo-compounds. The solid state structure of 7 was determined by X-ray crystallography. Complexes 7 and 8 are not active for ethylene/1-hexene copolymerization. Meanwhile, the complexes 18–20 are highly active and their activities are higher than that of the mononuclear analogue, 2-(η5-2,3,5-Me3C5H)C6H3NC6H11-κN}Ti(IV)Cl2 (21). The molecular weights of the polymers obtained with the bimetallic complexes 18–20 are higher than that of the polymer obtained using 21. Slightly higher contents of long-chain-branching are observed for the copolymers obtained using the bimetallic system.
双金属二氯钛配合物2,6-[η5-2,5-Me2C5H2]2-4-R-C6H2N-µN}Ti(IV)Cl2}2 (7, R = Me; 8, R = F)和4,4′-A[2-(η5-2,3,5-Me3C5H)C6H3NC6H11-κN}Ti(IV)Cl2]2 (18, A = CH2; 19, A = O; 20, A = ortho-C6H4)是通过2-二羟基硼酰基-3-甲基-2-环戊烯-1-酮(1)与二溴化合物进行铃木偶联反应的关键步骤制备的。7的固态结构通过X射线晶体学测定。配合物7和8对乙烯/1-己烯共聚反应不活跃。同时,配合物18-20具有高度活性,其活性高于单核类似物2-(η5-2,3,5-Me3C5H)C6H3NC6H11-κN}Ti(IV)Cl2 (21)。用双金属配合物18-20制备的聚合物的分子量高于用21制备的聚合