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。