A series of 2-(1-aryliminopropyl)-1,10-phenanthrolines (L1-L7) and their corresponding iron(II) chlorides (Fe1-Fe7) are synthesized and characterized by elemental and spectroscopic analyses. The molecular structures of 2-[1-(2,6-diisopropy1phenylimino)propyl]-1,10-phenanthroline (13) and (2-11(2,6-diethylphenylimino)propyl]-1,10-phenanthroline (L3) and {2-[1-(2,6-diethylphenylimino)propyl]-1,10-phenanthroline} center dot FeCl2 (Fe2) are determined by the single crystal X-ray diffraction. All iron complexes, activated with methylaluminoxane (MAO), exhibit high activities in ethylene oligomerization with high selectivity for alpha-olefins produced. Compared with other 2-imino-phenanthrolines, the title complexes show better thermal stability, and their oligomerization products are potentially more useful due to lower contents of butenes and waxes observed. (c) 2010 Elsevier B.V. All rights reserved.