Organic-inorganic hybrids based on polyoxometalates and copper coordination complexes

Two new hybrids based on Keggin polyoxometalates have been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, TG analysis, and single-crystal X-ray diffraction. The crystal structure analyses reveal that complex 1 has an infinite 1D chain structure, constructed from [Cu(2,2'-bpy)(4,4'-bpy)(H2O)] fragments and [H2PMo11VO40](2-) building blocks. Complex 2 has a 2D molecular ladder structure, with a basic structural unit composed of one bis(A mu-OH) dicopper(II) [Cu-2(OH)(2)(H2O)(2)(4,4'-bpy)(3)] fragment, one [HPMo12O40], and four water molecules. The [Cu-2(OH)(2)(H2O)(2)(4,4'-bpy)(3)] units connect alternately to form edge rails. The [HPMo12O40] clusters act as rungs of the ladder, linking pairs of Cu atoms from the two adjacent edge rails. The electrochemical behavior of the complexes in modified carbon paste electrodes and their electrocatalytic reduction of nitrite were investigated.