Ni(acac)2/Phosphine as an Excellent Precursor of Nickel(0) for Catalytic Systems

The coordination of phosphine ligands to nickel acetylacetonate was studied in toluene solution, and the first X-ray structure of the unstable complex trans- [Ni(acac) 2 (PMe 2 Ph) 2 ] has been reported. A convenient procedure was developed to generate Ni(0) species in situ in solution from a Ni(acac) 2 precursor, and their application in catalysis was demonstrated. A study of the reaction mechanism has suggested that water may play an important role in the formation of zerovalent nickel species. The nature of the Ni(0) species was confirmed by trapping with Ph 2 S 2, and the structure of the resulting complexes trans- [Ni(SPh) 2 L 2 ] was established by X-ray analysis for L = PMe 2 Ph, PMePh 2, PBu 3 .