A metal–organic framework based on Wells–Dawson polyoxometalates [As2W18O62]6 − template

A metal–organic framework based on Wells–Dawson polyoxometalate [As2W18O62]6 −, Co2(bpy)3(ox)(As2W18O62)·2(H2bpy)·2H2O (1) (bpy = 4,4′-bipyridine, ox = oxalate), has been synthesized hydrothermally by reacting Co(NO3)2, 4,4′-bipyridine, oxalate and K6As2W18O62. Single-crystal X-ray diffraction reveals that compound 1 contains a 3D cationic host framework composed of oxalate-bridged binuclear secondary building unit and 4,4′-bipyridine linkers. The channels of the 3D host framework are occupied by Wells–Dawson [As2W18O62]6 − templates. Thermogravimetric analysis shows the host framework keeps high thermal stability up to 450 °C. Furthermore, the electrochemistry property of 1 has been studied. The result indicates 1 has good electrocatalytic activity toward the reduction of nitrite.