Use of homogeneous catalytic systems which include as a pre-catalyst a complex of a group 4 metal and a Salan ligand in the polymerization of alpha-olefins, is disclosed. The Salan ligand is characterized by a sequential diamino-containing skeleton unit which is non-symmetric, and the pre-catalysts can also be such that are devoid of a symmetry element. The disclosed polymerization results in alpha-olefin polymers such as polypropylene which are characterized by high levels of tacticity. Also disclosed are novel Salan ligands and novel complexes thereof with group 4 metals.
揭示了在α-烯烃聚合中使用包括第4族
金属和Salan
配体的预催化剂的均相催化体系的用途。Salan
配体的特点是具有非对称的顺序二
氨基骨架单元,预催化剂也可以是不具有对称元素的。所揭示的聚合产物为α-烯烃聚合物,例如高度具有定向性的聚
丙烯。还揭示了新型的Salan
配体及其与第4族
金属的新配合物。