Structure and Properties of Transition‐Metal Complexes with Chiral C₂‐symmetric binucleating ligands

The coordination behavior of chiral binucleating ligands of type 1 – 4 with various transition metals has been investigated. 1 H‐NMR Titration experiments with zinc(II) salts gave detailed structural information about the structure of the resulting zinc complexes. Ligand 1 forms an unusual C 3 ‐symmetric dinuclear zinc complex [Zn 2 CIL 3 ] ( 8a ) which was characterized by X‐ray crystallography. Treatment of complex 8a with various carboxylic acids resulted in ligand‐exchange reactions. With ligand 2 , a hydroxo‐bridged dinuclear copper complex 15 was synthesized and its structure elucidated by X‐ray analysis. Solution studies UV and 1 H‐NMR spectroscopy of the reaction of ligand 3 with Zn II and N II salts revealed the formation of dimeric species of the type [M 2 X 4 L 2 ]. Ligand 4 formed well‐defined dinuclear complexes with Ni II and Cu II salts of which the corresponding Ni II complex [Ni 2 (AcO) 2 (ClO 4 ) 2 L] ( 22a ) was characterized by crystal‐structure analysis.