Organic-Inorganic Hybrids Constructed from Mixed-Valence Multinuclear Copper Complexes and Templated by Keggin Polyoxometalates

Five organic-inorganic hybrids containing mixed-valence multinuclear copper complexes and Keggin polyoxometalates, [(Cu5Cu3II)-Cu-I(ptz)(8)(H2O)] [HSiW12O40] (1), [(Cu10Cu2II)-Cu-I(ptz)(8)(Cl)(3)] [PW12O40] (2), [(Cu2Cu4II)-Cu-I(ptz)(6)(OH)-(H2O)(2)] [PW12O40] center dot 2H(2)O (3) (Cu2Cu5II)-Cu-I(ptz)(6)(OH)(2)SiW12O40 center dot 6H(2)O (4), and [(Cu2Cu5II)-Cu-I(ptz)(6)] [PMo(3)(V)Mo(VI)9O(40)]center dot 8H(2)O (5) (ptz = 5-(2-pyridyl)-tetrazole), were hydrothermally synthesized and structurally characterized. Compound 1 exhibits a three-dimensional (3D) network that features unprecedented double chains consisting of tetranuclear Cu clusters. Compound 2 displays a 3D network that has unusual Cl-centered hexanudear Cu clusters and Cl-bridged tetranuclear Cu units. Compound 3 shows a 3D supramolecular network extended by two-dimensional (2D) grid-like sheets which are composed of mixed-valence multinuclear copper chains and PW12 polyanions. Isostructural compounds 4 and 5 exhibit a 3D network consisting of 2D ladder-like copper-ptz layers and SiW12 (PMo12 in 5) polyanions. The roles of copper ions with different oxidation states and ptz ligands with different coordination modes in the construction of the copper-ptz frameworks are discussed. Their electrochemical properties were investigated as well.