Synthesis of allyl- and aryl-iminopyrrolyl complexes of nickel

The 2-iminopyrrole ligand precursors 2-C4H3NH[(R)C=N(2,4,6-C6H2Me3)] (R=H, I; R=Me, II) were synthesised and react with NaH to give the corresponding sodium salts 1 and 2, respectively. Salt 2 reacts with [NiPhBr(PPh3)(2)] to yield [NiPh(acetiminopyrrolyl)(PPh3)](3). Ligand precursors II and 2 react, respectively, with equimolar amounts of [NiMe2(TMEDA)] and [NiBr2(NCMe)(2)] to give [Ni(acetiminopyrrolyl)(2)] 4. Both 1 and 2 react with [Ni(eta(3)-C3H5)(mu-Br)](2) to give complexes [Ni(eta(3)-C3H5)(iminopyrrolyl)] 5 and 6. The crystal structures of ligand precursor II and of complex 3 are reported and compared. Complex 3 was tested for catalytic activity for the oligomerisation of ethylene and showed only moderate activity.