作者:Eric N. T. Cuthbert、Vincenzo Busico、David E. Herbert、Peter H. M. Budzelaar
DOI:10.1002/ejic.201900716
日期:2019.8.7
Zr and Hf complexes of bis(phenolate‐ether) (“O4”) ligands feature high activity, stereoselectivity and molecular weight capability for propene polymerization at high temperature. Here we report a simplified ligand synthesis and several new examples of O4 ligands. The formation of precatalysts LMR2 (M = Zr, Hf; R = Bn, Me) from LH2 and MR4 was found to be accompanied in some cases by the formation
双(酚盐醚)(“ O4”)配体的Zr和Hf配合物具有高温下丙烯聚合的高活性,立体选择性和分子量能力。在这里,我们报告了简化的配体合成和O4配体的几个新实例。由L H 2和MR 4形成的预催化剂L MR 2(M = Zr,Hf; R = Bn,Me)在某些情况下伴随着二聚物(µ-L)2 [MR 2 ]的形成。2,并且已经确定了两个这样的二聚体的X射线结构。用[Ph 3 C] + [B(C)处理L MMe 26 F 5)4 ] –产生相当干净的阳离子物种L MMe +,通过1 H NMR研究。二维ROESY数据尤其表明,对于“较小”的O4配体,L MMe +阳离子可逆地从活性形式(fac / fac)重新排列为大概无活性的fac / mer或mer / mer形式;更大的取代基似乎抑制了这种重排。讨论了聚合催化的意义。