A series of inorganic–organic complexes based on polymolybdate anions and copper–organic subunits, [Cu(H2O)(bim)2]{[Cu(Hbim)2][P2Mo5O23]}·2H2O (1), [Cu(Hbim)2]{[Cu(bim)(H2O)2]2[Cu(bim)2]2[(P2Mo5O23)2]}·20H2O (2), [Cu(phen)(H2O)][Cu(bim)2]2[P2Mo5O23]·H2O (3) and Mg[Cu(bim)(H2O)]2[P2Mo5O23]·4H2O (4) (bim = 2,2′-biimidazole, phen = 1,10-phenanthroline), have been synthesized under hydrothermal conditions and their crystal structures have been determined by single-crystal X-ray diffraction analysis. All of these compounds contain the [P2Mo5O23]6− polyoxoanions as building units. The structure determination shows that the polyoxoanion of compound 1 is mono-supported by one copper complex subunit. In compound 2, the [P2Mo5O23]6−cluster is supported by two distinct [Cu(bim)(H2O)2]2+ and [Cu(bim)2]2+ fragments. Compound 3 presents a tri-supported polyoxometalate cluster structure, where each [P2Mo5O23]6− anion is decorated by two [Cu(bim)2]2+ and one [Cu(phen)(H2O)]2+ cations. In compound 4, the [P2Mo5O23]6− anion is supported by four symmetry [Cu(bim)(H2O)]2+ units. The cyclic voltammetry results for 1–4 indicate the known fingerprint of the [P2Mo5O23]6− anion. Although compounds 1–4 contain similar polyoxometalate anions, the mean peak potentials are slightly different, due to their different chemical environments. The magnetic behaviours of 1–4 were also investigated, in the temperature range of 2–300 K.
