Structure–reactivity relationships in SHOP-type complexes: tunable catalysts for the oligomerisation and polymerisation of ethylene

Abstract

For over 30 years complexes with the general formula [NiPh(P,O)L] (L = tertiary phosphine; P,O = chelating phosphanylenolato ligand) have been used as highly efficient oligomerisation catalysts suitable for the production of linear α-olefins. The same complexes, which are usually referred to as SHOP-type catalysts (SHOP = Shell Higher Olefin Process) can also be used as ethylene polymerisation catalysts, provided they are treated with a phosphine scavenger that selectively removes the tertiary phosphine ligand (L). This Perspective examines the impact of various parameters (influence of the substituents, backbone size, solvent, use of cocatalysts, etc.) on the catalytic outcome of the complexes. Overall, this review shows that the selectivity and activity of the catalyst may be tuned efficiently through directed modification of the P,O chelator.