Sandwich-type polyoxotungstate hybrids decorated by nickel-aromatic amine complexes

Three new sandwich-type polyoxotungstates (POTs) decorated by nickel-2,2′-bpy complexes [{Ni(2,2′-bpy)2(H2O)}2{Ni(2,2′-bpy)}2 {Ni4(H2O)2(B-α-XW9O34)2}]n− (X=PV, n=4 for 1; X=AsV, n=4 for 2; X=GeIV, n=4 for 3) (2,2′-bpy=2,2′-bipyridine) were successfully synthesized under hydrothermal conditions and structurally characterized by elemental analyses, IR spectroscopy, single-crystal X-ray diffraction, and magnetic properties. Single-crystal structural analyses indicate that 1 and 2 are isostructural and both crystallize in the monoclinic space group C2/c, whereas 3 belongs to the triclinic space group P1¯. To our knowledge, 1, 2 and 3 represent rare examples of the organic–inorganic hybrid sandwich-type polyoxometalates functionalized by multiple nickel-aromatic amine complexes. Magnetic measurements of 1 exhibit the presence of ferromagnetic interactions within the rhombic tetranuclear-NiII cluster.

Graphical abstractThree new sandwich-type polyoxotungstates (POTs) decorated by nickel-2,2'-bpy complexes were successfully synthesized under hydrothermal conditions and structurally characterized.Figure optionsDownload full-size imageDownload as PowerPoint slide