Coexistence of Five Different Copper(II)−Phenanthroline Species in the Crystal Packing of Inorganic−Metalorganic Hybrids Based on Keggin Polyoxometalates and Copper(II)−Phenanthroline−Oxalate Complexes

Reaction of in situ generated copper(II)-monosubstituted Keggin polyoxometalates and copper(II)−phenanthroline−oxalato complexes in ammonium or rubidium acetate buffers led to the formation of the hybrid inorganic−metalorganic
compounds E4[Cu(phen)(H2O)4]2[Cu4(phen)4(H2O)4(ox)3]0.6[Cu2(phen)2(H2O)4(ox)]0.4[Cu(phen)(ox)]0.8[{SiW11O39Cu(H2O)}2{Cu2(phen)2(ox)}]·20H2O [E:  Rb (1), NH4 (2)]. The two compounds have been characterized by means of
elemental analysis, thermogravimetry, infrared and electron paramagnetic resonance spectroscopies, and magnetic
susceptibility measurements, and their structures have been established by single-crystal X-ray diffraction. Both
compounds are isostructural, and they contain a discrete bimolecular hybrid polyanion and several types of copper−phenanthroline complexes of variable nuclearity. The main structural features of these compounds are the presence
of the new hybrid POM [{SiW11O39Cu(H2O)}2{Cu2(phen)2(μ-ox)}]10-, where the dinuclear copper−oxalato complex
is sandwiched by two copper-monosubstituted POMs, and the coexistence of five different copper−phenanthroline
species with nuclearities ranging from one to four.