Bis(Μ-4-Methyl­Benzoato-Κ2 O:O′)Bis­[Aqua­(4-Methyl­Benzoato-Κ2 O,O′)Zinc(II)]–Bis­(Μ-4-Methyl­Benzoato-Κ2 O:O′)Bis­[(4-Methyl­Benzoato-Κo)(Nicotinamide-Κn)Zinc(II)]–Water (1/1/2)

Abstract

The crystal structure of the title compound, [Zn2(C8H7O2)4(H2O)2]·[Zn2(C8H7O2)4(C6H6N2O)2]·2H2O, consists of two kinds of dinuclear ZnII complexes (complex A and complex B) and uncoordinated water mol­ecules. In complex A, [Zn2(C8H7O2)4(H2O)2], each Zn cation is chelated by a 4-methyl­benzoate (PMB) anion and coordinated by a water mol­ecule, and is further bridged by two PMB anions in a trigonal-bipyramidal geometry. In complex B, [Zn2(C8H7O2)4(C6H6N2O)2], each ZnII cation is coordinated by a monodentate PMB anion and one nicotinamide (NA) ligand, and is further bridged by two PMB anions in a tetra­hedral geometry. Weak intra-mol­ecular π–π stacking between adjacent benzene rings is observed in complex B, the centroid–centroid distance being 3.710 (2) Å. Extensive O—H⋯O and N—H⋯O hydrogen bonding and weak C—H⋯O hydrogen bonding is present in the crystal structure. The crystal studied was a racemic twin; the minor twin component refined to 38%.