Hydrothermal Syntheses, Crystal Structures, And Magnetic Properties of a Series of Complexes Constructed from Multinuclear Copper Clusters and Polyoxometalates

A series of complexes constructed from multinuclear copper clusters and polyoxometalates, namely, [Cu6(PO4)2(H2O)2(bpy)6](H3O)2[P2W18O62](bpy=2,2′-bipyridine, 1), [Cu6(PO4)2(H2O)4(phen)6](H2O)2[P2W18O62] (phen = 1,10-phenanthroline, 2), [Cu2Cl(phen)4][PW12O40] (3), [Cu4(HPO4)2(H2O)4(phen)4](H3O)2[PV3W9O40] (4), and [Cu4(HPO4)2(H2O)2(bpy)4](H2O)2[PVW11O40] (5), have been successfully synthesized in situ under hydrothermal conditions via changing the ligand, adjusting the pH value, and introducing low-valence metal (V5+). Complex 1 represents the first example of 1D linear chain constructed from alternating mixed-valence hexacopper (four Cu2+ and two Cu+) clusters and Wells−Dawson type polyoxometalates. Complex 2 exhibits an unprecedented 2D layer network based on hexacopper phosphate and Wells−Dawson type polyoxometalates. Complex 3 constructed from dicopper coordination compounds and Keggin polyoxometalates, was obtained from the similar hydrothermal treatment of 2 at much lower pH value. Complexes 4−5 represent the first two examples of 1D linear chain constructed from alternating tetracopper phosphate cations and V5+-substituted Keggin type polyoxometalates. The magnetic properties of the complexes have been investigated between 2 and 300 K.