摘要/Abstract

首先合成单取代和双取代杂环膦化合物R-PPh₂[R=2-吡啶基（3a），2-噻吩基（3b），2-呋喃基（3c）]和Ph₂P-R'-PPh₂[R'=2，6-吡啶基（6a），2，5-噻吩基（6b），2，5-呋喃基（6c）].然后与叠氮三甲基硅烷发生Staudinger反应生成相应的杂环膦亚胺配体R-PPh₂（NSiMe₃）和（Me₃SiN）Ph₂P-R'-PPh₂（NSiMe₃）.最后与环戊二烯三氯化钛反应脱去三甲基氯硅烷后得到具有烯烃聚合催化活性的杂环膦亚胺钛配合物.所有配合物结构都经过核磁的确认，为了进一步确定配合物分子结构，利用单晶X射线衍射解析了所有钛配合物的晶体结构.在助催化剂甲基铝氧烷（MAO）活化作用下，双钛中心配合物6a~6c比单钛中心类似配合物3a~3c表现出更高的催化乙烯聚合活性，所得聚合物具有较宽分子量分布呈双峰分布，6b在较低聚合温度下就可以制备超高分子量聚乙烯.
关键词: 双金属钛配合物, 杂环基团, 膦亚胺, 乙烯聚合
Mono-and bisdiphenyl substituted heteroarylphosphines R-PPh₂[R=2-pyridyl (3a), 2-thienyl (3b) and 2-furyl (3c)] and Ph₂P-R'-PPh₂[R'=2,6-pyridyl (6a), 2,5-thienyl (6b) and 2,5-furyl (6c)] were synthesized. After Staudinger reaction with Me₃SiN₃, those heteroarylphosphines were converted into the heteroarylphosphinimine ligands, R-PPh₂(NSiMe₃) and (Me₃SiN)Ph₂P-R"-PPh₂(NSiMe₃). The subsequently dehalosilylation reaction with CpTiCl₃ afforded the corresponding Ti heteroarylphosphinimine halfmetallocenes as olefin polymerization catalysts. The structures of all the complexes were determined by means of ¹H NMR, ¹³C NMR and ³¹P NMR spectroscopic methods and further confirmed by single-crystal X-ray diffraction analysis. When activated with methylaluminoxane (MAO) at a ratio of Al/Ti=600 and under 0.5 MPa of ethylene, these bimetallic Ti phosphinimine complexes displayed a higher catalytic activity compared to the monometallic analogues, but resulted in polymers with bimodal molecular weight distributions. Unexpectedly, 6b produced ultrahigh M_w polyethylene at lower polymerization temperature.
Key words: bimetallic titanium catalyst, heteroaryl, phosphinimine, ethylene polymerization


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