Tetrakis[mu-4-(methylamino)benzoato-kappa O-2:O ']bis[(N,N-diethylnicotinamide-N-1)zinc(II)] dihydrate

Abstract

The title molecule, [Zn-2(C8H8NO2)(4)(C10H14N2O)(2)]center dot 2H(2)O, is a centrosymmetric binuclear complex, with two Zn-II ions [Zn center dot center dot center dot Zn' = 2.9301 (4) angstrom] bridged by four methylaminobenzoate (MAB) ligands. The four nearest O atoms around each Zn-II ion form a distorted square-planar arrangement with the distorted square-pyramidal coordination completed by the pyridine N atom of the N,N-diethylnicotinamide (DENA) ligand. Each Zn-II ion is displaced by 0.3519 (2) angstrom from the plane of the four O atoms, with an average Zn-O distance of 2.030 angstrom. The dihedral angles between carboxylate groups and adjacent benzene rings are 10.57 (10) and 16.63 (12)degrees, while the benzene rings are oriented at a dihedral angle of 81.84 (5)degrees. The pyridine ring is oriented at dihedral angles of 40.49 (6) and 51.25 (6)degrees with respect to the benzene rings. In the crystal structure, intermolecular O-H center dot center dot center dot O and N-H center dot center dot center dot O hydrogen bonds link the molecules into a three-dimensional network. The pi-pi contact between the inversion-related pyridine rings [centroid-centroid distance = 3.633 (1) angstrom] may further stabilize the crystal structure.