title: Two hexa-TM-containing (TM = Co2+ and Ni2+) {P2W12}-based trimeric tungstophosphates.
abstract: Reactions of hexavacant polyoxotungstates [H(2)P(2)W(12)O(48)](12-) ({P(2)W(12)}) with transition-metal (TM), and alkali-metal ions lead to the isolation of two hexa-TM-containing polyoxotungstates Na(15)[Na(3) subset {M(H(2)O)(4)}(6){WO(H(2)O)}(3)(P(2)W(12)O(48))(3)].xH(2)O (M = Co(2+), x = 109 for 1; M = Ni(2+), x = 110 for 2). Single-crystal X-ray diffraction analysis revealed that compounds 1 and 2 both crystallized in the orthorhombic system, space group Cmcm, with lattice constants a = 21.353(3) A, b = 32.114(3) A, c = 33.848(4) A, for 1; a = 21.643(6) A, b = 31.870(6) A, c = 33.861(7) A for 2. Polyoxoanions [Na(3) subset {M(H(2)O)(4)}(6){WO(H(2)O)}(3)(P(2)W(12)O(48))(3)](15-) in 1 and 2 exhibit a crown-type structure composed of a [{WO(H(2)O)}(3)(P(2)W(12)O(48))(3)](18-) (abbreviated as {P(6)W(39)}) shell encapsulating six TM ions and three Na(+) cations. Polyoxoanions 1 and 2 represent the first hexa-TM-containing {P(2)W(12)}-based trimeric POMs, which offer new examples with the potentially aqua-ligand-induced capability of "trapping" metal ions in the {P(6)W(39)} shell. Electrocatalytic studies show that compounds 1 and 2 display electrocatalytic activity to reduce nitrite.
authors.affiliation: Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Renmin Street No. 5268, Changchun, Jinlin 130024, P. R. China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Yao
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Zhang
authors.forename: Yangguang
authors.initials: Y
authors.lastname: Li
authors.forename: Enbo
authors.initials: E
authors.lastname: Wang
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008968:Molecular Conformation; D009532:Nickel / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D028561:Transition Elements; D014414:Tungsten / Q000737:chemistry*
chemical_list: D010710:Phosphates; D011108:Polymers; D028561:Transition Elements; D003035:Cobalt; D009532:Nickel; D014414:Tungsten