某些过渡金属组成的Ziegler-Natta催化剂聚合共轭双烯烃,所得聚合物的微观结构易随聚合条件和主催化剂配体的改变而异.具有d电子的钴、钛催化体系聚合丁二烯,既可得cis-1,4结构聚丁二烯,又可得1,2结构的聚丁二烯;而具有f电子的稀土催化剂聚合共轭双烯烃,无论怎样改变其聚合条件和配体,一般皆得高顺式聚合物.一般认为:这种定向性的特征是由单体向活性中心上配位、插入时的环境及活性中心的本质所决定的.在第一报中作者利用同一种配位体,使具有d电子的过渡金属Fe和具有f电子的稀土 Some transition metal Ziegler-Natta catalyst polymerization of conjugated dienes, the microstructure of the resulting polymer easily with the polymerization conditions and the main catalyst ligand changes with a d-electron cobalt, titanium catalytic system polymerization of butadiene, Both available cis-1,4 structure of polybutadiene, but also available 1, 2 structure of polybutadiene; and f-electron rare earth catalyst for the polymerization of conjugated dienes, no matter how changing its polymerization conditions and ligands, In general, it is believed that this directional characteristic is determined by the nature of the coordination and insertion of monomers into the active center and the environment and active center of the insertion.In the first report, the authors used the same The ligands are such that the transition metal Fe with d electrons and the rare earth with f electrons