Tris(1,10-phenanthroline-κ2N,N')iron(II) bis(2,4,5-tricarboxybenzoate) monohydrate and tris(2,2'-bipyridine-κ2N,N')iron(II) 2,5-dicarboxybenzene-1,4-dicarboxylate-benzene-1,2,4,5-tetracarboxylic acid-water (1/1/2).

The title compounds, tris(1,10-phenanthroline-κ(2)N,N')iron(II) bis(2,4,5-tricarboxybenzoate) monohydrate, Fe(C(12)H(8)N(2))(3)(2)·H(2)O, (I), and tris(2,2'-bipyridine-κ(2)N,N')iron(II) 2,5-dicarboxybenzene-1,4-dicarboxylate-benzene-1,2,4,5-tetracarboxylic acid-water (1/1/2), Fe(C(10)H(8)N(2))(3)·C(10)H(6)O(8)·2H(2)O, (II), were obtained during an attempt to synthesize a mixed-ligand complex of Fe(II) with an N-containing ligand and benzene-1,2,4,5-tetracarboxylic acid via a solvothermal reaction. In both mononuclear complexes, each Fe(II) metal ion is six-coordinated in a distorted octahedral manner by six N atoms from three chelating 1,10-phenanthroline or 2,2'-bipyridine ligands. In compound (I), the Fe(II) atom lies on a twofold axis in the space group C2/c, whereas (II) crystallizes in the space group P2(1)/n. In both compounds, the uncoordinated carboxylate anions and water molecules are linked by typical O-H···O hydrogen bonds, generating extensive three-dimensional hydrogen-bond networks which surround the cations.