Salphen Bimetallic Organotitanium Olefin Polymerization Catalysis: Marked Cooperativity Without Sacrificing Activity
In Nature, multimetallicmetalloenzyme active sites play key roles in organizing reactive functional groups to achieve enhanced turnover frequencies and product selectivities.Inspired by such biocatalysts,bimetallic complexes have emerged as powerful polymerization catalysts, and metal…metal cooperative effects dramatically and instructively impact polymer microstructure--enhanced branching, α-olefin comonomer enchainment selectivity, and higher Mw (or Mn) versus the mononuclear counterparts.1 Nevertheless, despite these unusual, attractive, and potentially useful effects, the binuclear catalysts invariably exhibit lower activity than their mononuclear analogues.2-4 We report here the synthesis of a series of salphen bimetallic complexes having readily incorporated Ti(Cp)Me2 or Ti(Cp*)Me2moieties (Figure 1).It will be seen that the ancillary Cp and Cp* ligands enhance catalyst stability, and that these new bimetallic catalysts exhibit significantly enhanced polymerization activity in both homo-and copolymerizations versus the mononuclear analogues.This is the first case for a bimetallic catalyst which exhibits marked cooperativity without sacrificing activity for olefin polymerization.
Shaofeng Liu Zhibo Li
School of Polymer Science and Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Rd., Qingdao, 266042
国际会议
9th International Symposium on High-Tech Polymer Materials(第9届国际高技术高分子材料学术会议)(HTPM-9)
郑州
英文
12-12
2016-07-11（万方平台首次上网日期，不代表论文的发表时间）