An Organic-inorganic Hybrid Sandwich-type Arsenotungstate [H_2dap]_2H_2[Ni(dap)_2][Ni(dap)_2(H_2O)_2]- [Ni_4(H_2O)_2(B-α-As^VW_9O_(34))_2]·8H_2O

A new organic-inorganic hybrid sandwich-type arsenotungstate[H2dap]2H2[Ni（dap）2] [Ni（dap）2（H2O）2][Ni4（H2O）2（B-α-AsVW9O34）2]·8H2O 1 （dap = 1,2-diaminopropane） has been synthesized by the reaction of Na6[AsIII2W21O69（H2O）]·nH2O, NiCl2·6H2O and dap under hydrothermal conditions and structurally characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction. 1 crystallizes in the monoclinic space group P21/n with a = 13.5133（19）, b = 19.043（3）, c = 17.647（2）, β = 102.585（2）°, V = 4432.0（11） 3, T = 296（2） K, Z = 2, μ = 25.350 mm–1, GOOF = 1.058, R = 0.0353 and wR = 0.0838. The molecular unit of 1 consists of two diprotonated [H2dap]2＋ cations, two protons, one four-coordinate [Ni（dap）2]2＋ cation, one six-coordinate [Ni（dap）2（H2O）2]2＋ cation, one classic tetra-NiII substituted sandwich-type [Ni4（H2O）2（B-α-AsVW9O34）2]10– polyoxoanion and eight lattice water molecules. Furthermore, some reported different types of transition-metal substituted sandwich-type polyoxoanions are summarized and compared.

Synthesis and crystal structure of a novel double 1:11 series arsenotungstate: [Cu^I(phen)_2]_5H_6[Sm(AsW_(11)O_(39))_2]·6H_2O

A novel double 1：11 series arsenotungstate, [Cu^I（phen）2]5H6[Sm（AsW11O39）2]·6H2O （phen=1, 10-phenanthroline） was synthesized by the hydrothermal method and characterized by elemental analysis, 1R spectra, and single-crystal X-ray diffraction. The title compound was monoclinic, space group P2 1/c, a=3.75710（2） nm, b=1.39776（8） nm, c=-3.33735（18） nm, β=96.967（10）°, V=17.3969（17） nm^3, Z=4. Single crystal X-ray structural analyses revealed that the dimeric polyanion, [SmAs2W22O78]^1-, consisted of one central Sm^3＋ ion and two tetradentate heteropoly ligands [ASW11O39]^7-. The Sm^3＋ ion and two tetradentate defective [AsW11O39]^7- anions were joined together by the sharing of four oxygen atoms from each heteropoly ligand. The bond valence sum （BVS） calculations of the title compound suggested that all four Cu atoms were in the ＋1 oxidation sate.

DL-Serine covalently modified multinuclear lanthanide-implanted arsenotungstates with fast photochromism

A series of DL-serine covalently modified multinuclear lanthanide implanted arsenotungstates K_(2)[{Ln(H_(2)O)_(7)}_(2){As_(4)W_(44)O_(137)(OH)_(18)(H_(2)O)_(2)(DL-Ser)_(2)}{Ln_(2)(H_(2)O)_(5)(DL-Ser)}_(2)]·65H_(2)O(DL-Ser=DL-serine,Ln=La(1),Ce(2),Pr(3))are obtained.Crystal structure analysis shows that these compounds are isomorphic and contain the basic[{As_(4)W_(44)O_(137)(OH)_(18)(H_(2)O)_(2)(DL-Ser)_(2)}{Ln_(2)(H_(2)O)_(5)(DL-Ser)}_(2)]^(8–)polyoxoanion constituted by two{As_(2)W_(19)O_(59)(OH)_(8)(H_(2)O)}^(6–)subunits,a[W_(6)O_(2)_(3)(OH)_(2)(DL-Ser)_(2)]_(14)–fragment,and two embedded[Ln_(2)(H_(2)O)_(5)(DL-Ser)]^(5+)groups,which further build into one dimensional linear chainlike structure via two peripheral Ln^(3+)ions.Most remarkably,these compounds exhibit rapid photochromic behaviors,which changed color quickly from white(1),yellow(2),green(3)to blue(1),brown(2)and glaucous(3)in ten minutes under UV irradiation,and that the colors gradually recovered in the dark for approximately 22 h.

An unprecedented dumbbell-shaped pentadeca-nuclear W-Er heterometal cluster stabilizing nanoscale hexameric arsenotungstate aggregate and electrochemical sensing properties of its conductive hybrid film-modified electrode

Cluster-based functional materials have made remarkable progress owing to their wonderful structures and distinctive physicochemical performances,one of on-going advancements of which is basically driven by synthetic chemistry of exploring and constructing novel nanosized gigantic polyoxometalate(POM)aggregates.In this article,an unprecedented nanoscale hexameric arsenotungstate aggregate Na_(9)K_(16)H_(4)[Er_(0.5)K_(0.5)(H_(2)O)_(7)][Er_(5)W10O_(2)6(H_(2)O)_(14)][B-α-AsW_(9)O_(33)]_(6)·102H_(2)O(1)has been synthesized by the combined synthetic strategy of simultaneously using the arsenotungstate precursor and simple tungstate material in a highly acidic aqueous solution.The{[Er_(5)W_(10)O_(26)(H_(2)O)_(14)][B-α-AsW_(9)O_(33)]6}31-polyanion in 1 consists of an intriguing dumbbell-shaped pentadeca-nuclear W-Er heterometal{Er_(5)W10O_(2)6(H_(2)O)_(14)}^(23+)cluster connecting six trilacunary[B-α-AsW_(9)O_(33)]^(9-)moieties,which has never been seen previously.Furthermore,through electropolymerization of 1 and pyrrole on the conductive substrate,a thickness-controllable and robust 1-PPY(PPY=polypyrrole)hybrid film was successfully prepared,which represents the first POM-PPY film assembled from high-nuclear lanthanide(Ln)encapsulated POM and PPY hitherto.The 1-PPY film-based electrochemical biosensor exhibits a favorable recognition performance for ochratoxin A in multiple media.This work not only provides a feasible combined synthetic strategy of the POM precursor and simple tungstate material for constructing complicated multi-Ln-inserted POM aggregates,but also offers a promising electrochemical platform constructed from POM-based conductive films for identifying trace biomolecules in complex environments.