Complexes based on four-membered cyclic anionic six-electron-donor ligands

摘要

A single-site olefin polymerization catalyst and method of making it are disclosed. The catalyst comprises an activator and an organometallic complex. The complex comprises a Group 3 to 10 transition metal, M, and at least one anionic heterocyclobutenyl ligand that is bonded to M. Molecular modeling results indicate that single-site catalysts based on anionic heterocyclobutenyl ligands will have advantages compared with the performance of catalysts based on cyclopentadienyl and substituted cyclopentadienyl ligands.