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.