Synthesis and crystal structures of novel β-diketiminato-lithium, iron, cobalt, nickel, zirconium complexes and their catalytical behaviors in polymerization of ethylene

Treatment of azaallyl-lithium with equal portion of 1-piperidinecarbonitrile gave mix-substituted β-diketiminato-lithium 2. Double ratio of 2 with FeCl2, CoCl2 and NiCl2·6H2O yielded the β-diketiminate iron 3, cobalt 4, nickel 5, or equivalent of ZrCl4 led to zirconium complex 6, respectively. The structural features of these complexes were described, and the catalytical behaviors of the complexes 3–6 for the polymerization of ethylene were investigated.