No 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 alpha-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 co-catalysts, 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.

The chemistry of nickel(N-heterocyclic carbene) species has blossomed at the beginning of this century with a particularly rapid acceleration in the last 5 years, as indicated by the fact that more than 65% of the discussed research articles in this comprehensive review date from the period 2010-2015. The rapid evolution of this chemistry has led to an increasing number of applications in the field of catalytic C-heteroatom bond formation, reduction and oxidation where the heteroatom is either nitrogen, sulfur, oxygen or boron. Thus, in addition to the development of aryl aminations, aryl thiolations, alkyne hydrothiolations, and transfer hydrogenations, which are the most ancient reactions of this type known for these systems, the last five years have seen the appearance of a number of novel interesting Ni(NHC)-catalyzed transformations such as the dehydrogenative cross-coupling of aldehydes and amines or alcohols, the hydroamination of alkenes, the hydroimination of alkynes, a one-step indoline synthesis,