Structural characterization of Group 4 transition metal halide bis-Arduengo carbene complexes MCl4L2:
作者:Martin Niehues、Gerald Kehr、Gerhard Erker、Birgit Wibbeling、Roland Fröhlich、Olivier Blacque、Heinz Berke
DOI:10.1016/s0022-328x(02)01731-x
日期:2002.12
trans-(imidazol-2-ylidene)MCl4 complexes 4a–c (M=Zr) and 5a (M=Hf), respectively. These four Arduengo carbene-Group 4 metal halide complexes were characterized by X-ray diffraction. The pairs of carbene ligands are trans-positioned in a pseudo-octahedral coordination geometry at the Group 4 metals, and adopt a conformational orientation in the solid state where the two five-membered heterocycles are arranged
Arduengo Carbenes 1,3-二异丙基-,1-甲基-3-(1-甲基丙基)-和1-甲基-3-(2,4,6-三甲基苄基)咪唑-2-亚烷基(3a – c)为与MCl 4(thf)2(M = Zr,Hf)反应,分别得到各自的反式-(咪唑-2-亚甲基)MCl 4配合物4a – c(M = Zr)和5a(M = Hf)。这四种Arduengo卡宾-第4组金属卤化物配合物通过X射线衍射表征。卡宾配体对是反式的在第4族金属上以伪八面体配位几何构型排列,并在固态中采用构象取向,其中两个五元杂环共面排列并平分ClMCl角。DFT计算表明,这些化合物中Arduengo carbenes用作纯的σ-供体配体,并且优选的构象配体取向基于空间原因。当在甲苯中用大量过量的甲基铝氧烷活化时,配合物4a – c形成中等活性的乙烯聚合催化剂。