Dipicolinate Oxovanadium(IV) Complexes - Well-Defined, Universal Precatalysts for Ethylene Polymerization and Polar Monomers Oligomerization

In the field of polymers and organometallic chemistry, a significant gap is apparent in the area of research on well-defined metal complexes targeted for using in catalysis leading to olefinic oligomers and polymers. Here, we report on the use in these processes the dipicolinate oxovanadium(IV) complexes, without and with auxiliary ligands, i. e. 1,10-phenanthroline and 2,2'-bipyridine. The investigated complexes turned out to be versatile precatalysts. After reaction with appropriate activator, they exhibited 11 times higher a catalytic activity than reference vanadium(IV) complexes with salen ligands - so far, precatalysts from a group of vanadium(IV) complexes with the highest known catalytic activity for polymerization of ethylene. In the case of the oligomerization of polar monomers (2-chloro-2-propen-1-ol and 3-buten-2-ol) the complexes described in this report have a catalytic activity (very high) similar to vanadium(IV) complexes known in the literature. The oxovanadium(IV) complexes: [VO(dipic)], [VO(dipic)(phen)], [VO(dipic)(bipy)] play role the precatalysts in both oligomerization and polymerization of olefinic monomers. The results shows that oxovanadium(IV) complexes belong to the group of catalysts with very high catalytic activity in these oligomerization processes. All oxovanadium(IV) complexes with EtAlCl2 or Et2AlCl are active toward ethylene. image