Oxidative additions to nickel(0): preparation and properties of a new series of arylnickel(II) complexes

A new series of stable arylnickel(II) complexes of the type (PPh3)2Ni(aryl)X (X=Cl, Br) were prepared by oxidative additions of aryl halides to Ni(PPh3)4, where aryl is not only an ortho-substituted, but also phenyl or a meta- or para-substituted aromatic ligand. The order of decrease in their thermal stability was o-tolyl > p-chlorophenyl > m- or p-tolyl.