Using Chiral Ligand Substituents To Promote the Formation of Dinuclear, Double‐Stranded Iron, Manganese, and Zinc Mesocates

The synthesis and structures of dinuclear manganese, iron, and zinc complexes of chiral di‐iminodipyrromethane ligands (L) are reported. Schiff base condensation reactions between 5,5′‐diformyl‐2,2′‐dipyrromethane and the chiral amines (–)‐( R )‐CH(Me) t Bu and (+)‐( R )‐CH(Me)Ph result in the straightforward synthesis of the new, chiral ligands H 2 L 2 and H 2 L 3 , respectively. Salt elimination reactions between K 2 L and divalent Mn and Fe halides, and protonolysis reactions between ZnMe 2 and H 2 L result in the formation of the new dinuclear complexes [M 2 (L) 2 ]. Investigation of the structures of these compounds in solution and in the solid state reveal that chiral mesocates are formed for L = L 2 , whereas for L = L 3 , a racemic mixture of helicates is present.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)