A novel reduced a-Keggin type polyoxometalate coordinated to two and a half copper complex moieties: [Cu(2,20-bipy)2][PMoVI 8MoV 4O40{Cu(2,20-bipy)}2.5]$H2O

A novel reduced polyoxometalate derivative [Cu(2,20-bipy)2][PMoVI 8MoV 4O40{Cu(2,20-bipy)}2.5]$H2O 1 has been hydrothermally synthesized and characterized by IR and XPS spectra, TG analysis and single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic system, space group P21/c, aZ21.620(4) A ° , bZ19.070(4) A ° , cZ17.810(4) A ° , bZ109.99(3)8, VZ6901(2) A ° 3, ZZ4. The result of structure determination shows that the reduced a-Keggin polyoxoanion [PMoVI 8MoV 4O40]7K is capped by two divalent Cu atoms through four bridging oxo groups on two opposite {Mo4O4} faces or pits and supports a half {Cu(2,20-bipy)} complex via the surface bridging oxygen atoms. q 2005 Elsevier B.V. All rights reserved.