Experimental

R factor = 0.039; wR factor = 0.098; data-to-parameter ratio = 25.0. In the complex anion of the title compound, (C2H6N5)-[Cu(C7H4NO4)(C7H3NO4)]3H2O, the CuII atom is coordi-nated by tridentate 6-carboxypyridine-2-carboxylate and pyridine-2,6-dicarboxylate ligands and is surrounded by four O atoms in the equatorial plane and two N atoms in axial positions in a distorted octahedral geometry. In the crystal, the components are linked into a three dimensional network by O—H O, N—H O, N—H N and C—H O hydrogen bonds and a – interaction with a centroid–centroid distance of 3.6080 (8) Å. Related literature For general background to and applications of supramolecula