Synthesis and characterization of two inorganic–organic hybrid polyoxometalates bridged by Keggin-type building blocks and copper(II) organonitrogen complexes

Two new inorganic–organic hybrid compounds, namely [Cu(dab)2]2[α-SiW12O40]·H2O (dab = 1,2-diaminobenzene) and [Cu(dafo)3]2[Cu(dafo)2(H2O)2][α-PMo12O40]2·4H2O (dafo = 4,5-diaza- fluorene-9-one) have been synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction. [Cu(dab)2]2[α-SiW12O40]·H2O exhibits an alternating 2D ladder-like structure built of [α-SiW12O40]4− and [Cu(L)2]2+ units. As the inorganic building block, the Keggin-type polyoxoanion [α-SiW12O40]4− is linked to two metal–organic complexes [Cu(dab)2]2+ through different kinds of oxygen atoms (terminal and bridging). [Cu(dafo)3]2[Cu(dafo)2(H2O)2][α-PMo12O40]2·4H2O shows an extended 3D supramolecular network via hydrogen bonding. Both complexes were characterized by physico-chemical and spectroscopic methods.