Two new organic–inorganic hybrid materials based on the polyoxotungstoaluminates

Two new organic–inorganic hybrid compounds, {[Cu(2,2′-bipy)2]2(Hbpy)[α-AlW12O40]}·H2O (1) and {[H2en][CuI(4,4′-bipy)]3(α-AlW12O40)}·4H2O (2) (2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine, py = pyridine, en = ethylene dimine) based on Keggin-type α-[AlW12O40]5− polyoxoaions and transition-metal organoamine subunits, have been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis (TG), and single-crystal X-ray diffraction. In addition, the electrochemical properties and photocatalytic activity of compound 1 were studied. The structural analysis reveals that 1 shows a 1D infinite chain structure constructed from [α-AlW12O40]5− polyoxoanions and {[CuII(2,2′-bipy)2][CuII(2,2′-bipy)(py)]}4+ fragments, in which the remarkable aspect is that [α-AlW12O40]5− polyoxoanion is modified in a fascinating symmetrical mode. Compound 2 displays an unprecedented 2D extended structure constructed from [α-AlW12O40]5− polyoxoanions and 4,4′-bipy-CuI-4,4′-bipy linear chains, in which three – chain belts formed by three linear chains arranged Cu parallel connect alternately with [α-AlW12O40]5− polyoxoanions. As far as we know, compounds 1 and 2 represent the first 1D and 2D extended hybrid materials constructed from 3d transition metals and polyoxotungstoaluminates linked through covalent bonds.