Chromium complex pre-catalysts in ethylene oligomerization/polymerization

Recent progress of chromium complex pre-catalysts in ethylene oligomerization and polymerization is reviewed herein. As well as the well-established trimerization of ethylene by chromium catalytic systems, such pre-catalysts have more generally been explored for ethylene oligomerization. Furthermore, chromium complex pre-catalysts have been found to exhibit high activities during ethylene polymerization. The catalytic activities can be influenced by the nature of ligands present, which can provide useful knowledge in determining structure-activity relationships. This review provides collective references concerned with the design of complex pre-catalysts with a view to ethylene reactivity