2-arylimino-9-phenyl-1,10-phenanthrolinyl-iron, -cobalt and -nickel complexes: Synthesis, characterization and ethylene oligomerization behavior

A series of 2-imino-9-phenyl-1,10-phenanthrolines 1-6 has been prepared and investigated as new tridentate N3 ligands in coordination with metal chlorides. Their iron(II) (1a-6a), cobalt(II) (1b-6b), and nickel(II) (1c-6c) complexes have been synthesized and characterized by elemental and spectroscopic analysis in conjunction with single-crystal X-ray diffraction studies. Some of the iron complexes show good activities in the selective dimerization of ethylene upon treatment with MAO or MMAO, while the cobalt complexes show higher activities than their iron analogues and lead to the formation of C-6 and C-8 oligomers. The nickel complexes display high catalytic activities toward ethylene oligomerization in the presence of Et2AlCl and an auxiliary ligand (PPh3). ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).