Ethylene trimerisation and tetramerisation catalysts with polar-substituted diphosphinoamine ligands.

Chromium-based catalyst systems with polar-substituted diphosphinoamine ligands are selective for either trimerisation or tetramerisation of ethylene, depending on the position of the polar groups on the aryl rings.

Highly selective chromium-based ethylene trimerisation catalysts with bulky diphosphinoamine ligands.

In situ prepared chromium catalysts containing bulky diphosphinoamine (PNP) ligands, upon activation with MAO, are extremely efficient catalysts for the trimerisation of ethylene to 1-hexene.