Complexes of 2,6-diacetylpyridine dioxime (dapdoH2). Crystal structures of [M(dapdoH2)2](ClO4)2 (M = Cu and Mn)

The family of compounds [M(dapdoH^sub 2^)^sub 2^](ClO^sub 4^)^sub 2^ (dapdoH^sub 2^ = diacetylpyridine dioxime; M = Mn, Co, Fe, Ni, Cu and Zn) were prepared and their properties studied and compared with the literature. The X-ray crystal structures of [Mn(dapdoH^sub 2^)^sub 2^](ClO^sub 4^)^sub 2^, (1), and [Cu(dapdoH^sub 2^)^sub 2^](ClO^sub 4^)^sub 2^, (5), are reported. Both exhibit the expected coordination sphere with six nitrogen atoms coordinated to the central metal, but each shows deformation from pseudo-octahedral geometry. In the case of (1), this takes the form of a significant tilting of one ligand, while in (5) the ligands are twisted toward each other, reducing the dihedral angle between them to 72°. In both cases, hydrogen bonding between the perchlorate ions and the oxime O-H groups links the units into chains. Attempts to prepare and crystallize the corresponding anions led to isolation of the oxidized products.[PUBLICATION ABSTRACT]