Stoichiometric Schiff base condensations of sterically bulky primary amines with acenaphthenequinone yield isolable monoimines. In the presence of iron(II) chloride, the remaining ketone reacts with a second primary amine bearing a pendant donor atom to give asymmetric, tridentate, α-diimine complexes that possess remarkable structural variability. A series of NNP and NNS tridentate iron(II) complexes are prepared; these coordination compounds become active catalysts ...