Organic–inorganic hybrids constructed by Anderson-type polyoxoanions and copper coordination complexes

Four organic–inorganic hybrid compounds based on Anderson-type polyoxoanions, namely, {[Cu(2,2′-bpy)(H2O)3]2[Cr(OH)6Mo6O18]}{[Cu(2,2′-bpy)(H2O)Cl][Cu(2,2′-bpy)(H2O)(NO3)][Cr(OH)6Mo6O18]}·18H2O (1), [Cu(2,2′-bpy)(H2O)2Cl]{[Cu(2,2′-bpy)(H2O)2][Cr(OH)6Mo6O18]}·4H2O (2), (H3O){[Cu(2,2′-bpy)(H2O)2]2[Cu(2,2′-bpy)(H2O)]2}[Cr(OH)6Mo6O18]3·36H2O (3), and (H3O){[Cu(2,2′-bpy)(H2O)2]2[Cu(2,2′-bpy)(H2O)]2}[Al(OH)6Mo6O18]3·33H2O (4), were isolated by conventional solution method, and crystal structures have been determined by single-crystal X-ray diffraction. Among them, compound 1 displays a discrete supramolecular structure, compound 2 shows a chainlike structure with chloro-copper complexes as counteranions, and compounds 3 and 4 are isomorphic and exhibit unique 3D open frameworks with lattice water molecules residing in the channels. The compounds 3 and 4 represent the first example of 3D organic–inorganic hybrid compounds in the TMs/2,2′-bpy/POMs system. Investigation of the reaction conditions reveals that the geometry and size of the anions together with its coordinating abilities to the metal centers have a decisive influence on both the composition and the dimensionality of the final compounds.