Synthesis, structure and electrochemical properties of a polyoxometalate-templated compound with 2D twofold interpenetrating network

A new Keggin-type polyoxometalate-based compound {[Cu-2(L)(4)(H2O)(4)](PW (11) (VI) (WO40)-O-V)}center dot 16H(2)O (1) constructed from PW (11) (VI) (WO40)-O-V (4-), N,N'-bis(4-pyridylformyl) piperazine (L) and Cu(II) has been hydrothermally synthesized and structurally characterized by elemental analyses, IR and single-crystal X-ray diffraction analysis. Single-crystal X-ray diffraction analysis reveals that the semi-rigid piperazine-based ligands L coordinate to the Cu(II) atoms to constitute a two dimensional coordination network. The 2D (4, 4) cationic layers are stacked together in a perpendicular mode, resulting in the formation of twofold interpenetrating frameworks with large cavities. The PW12 anions reside in the large cubic-like cavities, serving as non-coordinating templates. The compound 1 displays good electrocatalytic activity toward the reduction of nitrite in 1 M H2SO4 aqueous solution.