Syntheses, Structures And Properties Of Some New Polyoxotungstates Containing Transition Metal

The transition metal-containing polyoxotungstates have attracted great attention not onlystems from their intriguing variety of architectures, but also from their potential applicationsin the fields as diverse as catalysis, medicine, molecular magnetism and material science. Inrecent years, the synthesis of transition metal-containing polyoxotungstates has become animportant research area of the synthesis of polyoxometalates. In this paper, three classes of transition metal-containing polyoxotungstates (1-11) havebeen synthesized and characterized. Through a large number of studies we can somemeaningful conclusions:1. Germanotungstate with open Wells-Dawson structure: K13[{Co(H2O)}(μ-H2O)2(Ge2W18O66]·29H2O 1 [GeW9O34]10-is the perfect precursor for the synthesis of this class of compounds and thepresence of K+ is necessary for the formations of these compounds. The electrochemistryactivity of compound 1 shows the redox waves of transition metal, which is rare in othertransition metal-containing polyoxmetalates.2. Sandwich-type tungstobismutates containing low-valent heteroatom (BiIII):Na12[(Na(H2O)2)6(α-BiW9O33)2]?27H2O 2;Na18[(Cu(H2O))3(α-BiW9O33)2]?56H2O 3;Na 10 [Bi 2 W 20 M 2 O 70 (H 2 O) 6 ]?xH 2 O (M= Zn II 4,Ni II 5,Mn II 6,Co II 7)We have discussed in detail how the experimental conditions influnce the structures ofproducts and found an effective way to synthesize the tungstobismutates with Hervé andKrebs sandwich-types. The electrochemistry activities of these compounds indicate that MnIIand CoII were step oxide, which may have potential applications in the catalysis field.3. Compounds with one-to three-dimensional composed of paradodecatungstate-B clusterand transition metal as linkers: Na8[{Cd (H2O)2}(H2W12O42)]·32H2O 9, Na6[{Co(H2O)3}{Co(H2O)4}(H2W12O42)]·29H2O 10 and (H3O+)3[{Na(H2O)4}{Co (H2O)4}3 (H2W12O42)] 11Because there are many coordinated water and crystal water in compounds 11, it canreversibly adsorb and desorb water molecules leading to the color reversibly changing frompink to violet.Furthermore, the synthesis and structure of sandwich-type tungstobismutatesNa8[W2Co2(CoW9O34)2] ·54H2O 8 are reported in this paper.