Tetrahedral and octahedral coordination for zinc in polymeric tris(μ3-4-carboxyphenoxyacetato)di-μ3-hydroxo-bis(μ2-4,4′-bipyridine)tetrazinc(IV) dihydrate

The hydroxide group in the centrosymmetric title complex, {[Zn-4(C9H6O5)(3)(OH)(2)(C10H8N2)(2)].2H(2)O}(n), which adopts a three-dimensional network structure, bridges three Zn atoms. One of the symmetry-independent dicarboxylate groups chelates to a Zn-OH-Zn unit through the carboxyl group on the aromatic ring, while its other oxyacetate arm uses only one O atom for binding. The other dicarboxylate dianion is disordered over a center of inversion and functions as a chelating ligand to two Zn-OH-Zn units. The modes of coordination by the hydroxide, heterocycle and dicarboxylate ligands give rise to tetrahedral coordination for one Zn atom and octahedral coordination for the other.