Zirconium complexes in homogeneous ethylene polymerization

This article reviews the recent progress of zirconium complexes for ethylene polymerization. Zirconium complexes are one of the most important types of catalysts for homogeneous ethylene polymerization. Polymerization behavior and polymer structure can be adjusted through the balancing of ligand structure. We surveyed the zirconium complexes synthesized from 2006 to early 2009 and summarize their comparative catalytic activities. Generally, the main factor observed is the steric bulk which on increasing reduces the catalytic activity. Electron count, electronic cloud, and inductive effect also influence the catalytic activity.