Syntheses,crystal structures and electrochemical properties of three organic-inorganic hybrid supramolecular compounds based on copper-complex fragments and different polyoxometalates

Three new organic–inorganic hybrid compounds H[Cu^I(dafo)₂]₃{[Cu^I(dafo)₂]₂P₂W₁₈O₆₂} · H₂O (1), [Cu^I(dafo)₂]₃PMo₁₂O₄₀ (2) and [Cu^I(dafo)₂]₄SiW₁₂O₄₀ (3) (dafo = 4, 5-diazafluoren-9-one) have been hydrothermally synthesized and characterized by IR, TG and CV. Compound 1 exhibits a 3D supramolecular framework based on weak interactions between bisupported Dawson structure P₂W₁₈O₆₂ ⁶⁻ units and copper-complex fragments. With the aid of π–π stacking and hydrogen bonding interactions, a 1D supramolecular framework accommodating polyoxometalate (POM) anions is generated in 2. Compound 3 has similar fundamental units as 2, but the units are assembled in a different way. The distinction of their structures indicates that the POMs are the key factor in determining the frameworks of the final products. The electrochemical properties of these compounds have been studied using bulk-modified carbon paste electrodes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.