Anderson-type Polyoxoanions Research Articles

A New Organic-Inorganic Hybrid Based on L-Arginine and Polyoxoanion

Modifying polyoxometalates with organic and/or metal-organic moieties is a widely adopted method for broading the range of properties. In this work a new polyoxometalate constructed from Anderson-type polyoxoanions and L-arginine (Arg = L-arginine) molecules Na [CrMo6(OH)6O18]}(H2Arg)2·8H2O(1) has been synthesized via conventional method and characterized by routine techniques. Single-crystal X-Ray diffraction analysis shows that compound 1 is constructed by chiral L-arginine grafted Anderson-type clusters, sodium cation and water molecules which are further stabilized by hydrogen bonding interactions constitute 3D supramolecular networks. In addition, both antitumor behavior and photocatalytic activities of compound 1 were investigated.

Latent and active abPPO4 mushroom tyrosinase cocrystallized with hexatungstotellurate(VI) in a single crystal.

Tyrosinases, bifunctional metalloenzymes, catalyze the oxidation of monophenols and o-diphenols to o-quinones, the precursor compounds of the brown-coloured pigment melanin. In eukaryotic organisms, tyrosinases are expressed as latent zymogens that have to be proteolytically cleaved in order to form highly active enzymes. This activation mechanism, known as the tyrosinase maturation process, has scientific and industrial significance with respect to biochemical and technical applications of the enzyme. Here, not only the first crystal structure of the mushroom tyrosinase abPPO4 is presented in its active form (Ser2-Ser383) and in its 21 kDa heavier latent form (Ser2-Thr545), but furthermore the simultaneous presence of both forms within one single-crystal structure is shown. This allows for a simple approach to investigate the transition between these two forms. Isoform abPPO4 was isolated and extensively purified from the natural source (Agaricus bisporus), which contains a total of six polyphenol oxidases (PPOs). The enzyme formed crystals (diffracting to a resolution of 2.76 Å) owing to the employment of the 6-tungstotellurate(VI) salt (Na6[TeW6O24]·22H2O) as a cocrystallization agent. Two of these disc-shaped Anderson-type polyoxoanions [TeW6O24](6-) separate two asymmetric units comprising one crystallographic heterodimer of abPPO4, thus resulting in very interesting crystal packing.

1D Chain-Like Architecture in Anderson Heteropolymolybdate {[Eu(H2O)6]2(TeMo6O24)}·6H2O: Synthesis and Characterization

A new Anderson-based heteropolymolybdate {[Eu(H2O)6]2(TeMo6O24)}·6H2O (1) has been hydrothermally synthesized and characterized by elemental analyses, IR, thermal stability analysis, XRD and single crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P-1, a = 9.4023(6) A, b = 10.2530(7) A, c = 10.6525(10) A, α = 101.583(7)o, β = 108.024(7)o, γ = 107.150(6)o, V = 883.60(12) A3, Z = 1, R1 = 0.0338, wR2 = 0.0849. Compound 1 exhibits 1D chain-like structure formed by the alternative connection between Anderson type polyoxoanions [TeMo6O24]6− and Eu3+ along a-axis. Compound 1 displays good fluorescent emission of the Eu3+ ion at room temperature.

A host–guest hybrid framework with Anderson anions as template: synthesis, crystal structure and photocatalytic properties

A new Anderson-anion-templated inorganic–organic hybrid compound, H[(bitdc)Ni(H2O)3]2[IMo6O24]·6H2O (1) (bitdc = N,N′-bis(isonicotinoyl)-trans-1,2-diaminocyclohexane), has been synthesized and characterized by elemental analysis, IR spectroscopy, TG analysis, Powder XRD and single‐crystal X-ray diffraction. Compound 1 is made up of Anderson-type polyoxoanions [IMo6O24]5− and dinuclear [(bitdc)2Ni2(H2O)6]4+ coordination complexes to yield an intriguing 3D supramolecular host–guest structure. To our best knowledge, compound 1 represents the first example of host–guest compounds with Anderson anions as template. The photocatalytic properties and magnetic properties of 1 have been investigated.

Two large ionic crystals: Both their anions and cations constructed by Anderson-type POM-supported transition metal complex

Abstract Two large ionic crystals, [{Cu(C12N2H8)(H2O)3}2{Al(OH)6Mo6O18}][{Cu2(C2O4)(C12N2H8)2} {Al(OH)6Mo6O18}]·10H2O (1) ≡ [1c][1a]·10H2O ≡ 1 and [{Cu(C12N2H8)(H2O)3}2{Cr(OH)6Mo6O18}][{Cu2(C2O4)(C12N2H8)2} {Cr(OH)6Mo6O18}]·12H2O (2) ≡ [2c][2a]·12H2O ≡ 2, whose anions and cations constructed by Anderson–type POM–supported transition metal complex, have been isolated by conventional solution method, and characterized by elemental, IR, thermogravimetric, X-ray powder diffraction, EPR, magnetic and single-crystal X-ray diffraction analyses. Compounds 1 and 2 are isomorphic and consist of one-dimensional anion chains, which are constructed by alternating Anderson-type polyoxoanions and dinuclear copper complexes. 1D anions chains, 1c (2c) cations and lattice waters lead to their three-dimensional structures through hydrogen bonds and π–π interactions. The EPR studies and magnetic studies elucidate the electronic properties of the metal ions (Cu2+ or Cu2+/Cr3+), and the results are in good agreement with the structural feature of these compounds.

Two new architectures based on Anderson-type polyoxoanions and cadmium fragments

Two new hybrid compounds with cadmium cations/coordination complexes as linkers, (C 6H 5NO 2) 4[(H 2O) 14Cd 3(CrMo 6H 6O 24) 2] 1 (C 6H 5NO 2 = pyridine-4-carboxylic acid) and H[(H 2O) 2(C 6H 5NO 2)(C 6H 4NO 2)Cd] 2[CrMo 6H 6O 24]·9H 2O 2 (C 6H 5NO 2, C 6H 4NO 2 = pyridine-3-carboxylic acid), have been synthesized and characterized by elemental analyses, IR, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in the polar space group Pc and is made up of [CrMo 6H 6O 24] 3− polyoxoanions covalently linked by cadmium cations to yield an unprecedented one-dimensional chain, which represents the first example of one-dimensional assemblies based on Anderson-type POMs and cadmium cations. Adjacent inorganic chains are further in close contact by pyridine-4-carboxylic acid glues to form three-dimensional supramolecular polar networks via strong hydrogen-bonding interactions. Compound 2 exhibits a three-dimensional supramolecular channel framework constructed from cationic cadmium-pyridine-3-carboxylic acid coordination polymer sheets pillared by Anderson-type polyoxoanions, with dissociated water molecules situated in the channels. Furthermore, both of the compounds exhibit photoluminescent properties at ambient temperature.

A series of compounds based on the Anderson-type polyoxoanions and Cu-amino acid complexes

Three new compounds, [Cu(C 6H 8N 3O 2)(C 6H 9N 3O 2)(H 2O) 2][Na(H 2O) 2] 2[Al(OH) 6Mo 6O 18]·6H 2O ( 1), [Cu(C 6H 8N 3O 2)(C 6H 9N 3O 2)(H 2O) 2][Na(H 2O)] 2[Cr(OH) 6Mo 6O 18]·3H 2O ( 2) and [Cu(C 6H 10N 3O 2)(C 6H 9N 3O 2)(H 2O) 2][Al(OH) 6Mo 6O 18]·9H 2O ( 3) have been synthesized and characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction. In the structures of compounds 1 and 2, the sodium cations connected the Anderson-type polyoxoanions to form 1D zigzag chains, which are connected to 2D layers by the Cu-histidine complexes. Compound 3 is a contrast for them, when the reactant without sodium cations is used, a discrete structure is formed.

Synthesis and characterization of B-type Anderson polyoxoanions supported copper complexes with mixed ligands

Two novel compounds constructed by Anderson-type polyoxoanions and copper complexes with mixed ligands, (H 3O +)[Cu(C 6NO 2H 4)(phen)(H 2O)] 2[Al(OH) 6Mo 6O 18]·5H 2O (1) and (H 3O +)[Cu (C 6NO 2H 4)(phen)(H 2O)] 2[Cr(OH) 6Mo 6O 18]·5H 2O (2) have been isolated by conventional solution method, and characterized by elemental analyses, IR spectra, thermal stability analyses, X-ray powder diffraction and single-crystal X-ray diffraction. Compounds 1 and 2 are isomorphic and reveal an example of three-dimensional supramolecular organic–inorganic hybrids based on copper complexes with mixed 1,10-phenanthroline and pyridine-4-carboxylic acid ligands supported on Anderson-type polyoxoanions. Furthermore, both of the compounds exhibit photoluminescent properties at ambient temperature, and to elucidate the electronic properties of the metal ions (Cu 2+ or Cu 2+/Cr 3+), EPR studies have been performed, and the results are in good agreement with the structural feature of these compounds.

Organic–inorganic hybrids constructed by Anderson-type polyoxoanions and copper coordination complexes

Four organic–inorganic hybrid compounds based on Anderson-type polyoxoanions, namely, {[Cu(2,2′-bpy)(H 2O) 3] 2[Cr(OH) 6Mo 6O 18]}{[Cu(2,2′-bpy)(H 2O)Cl][Cu(2,2′-bpy)(H 2O)(NO 3)][Cr(OH) 6Mo 6O 18]}·18H 2O ( 1), [Cu(2,2′-bpy)(H 2O) 2Cl]{[Cu(2,2′-bpy)(H 2O) 2][Cr(OH) 6Mo 6O 18]}·4H 2O ( 2), (H 3O){[Cu(2,2′-bpy)(H 2O) 2] 2[Cu(2,2′-bpy)(H 2O)] 2}[Cr(OH) 6Mo 6O 18] 3·36H 2O ( 3), and (H 3O){[Cu(2,2′-bpy)(H 2O) 2] 2[Cu(2,2′-bpy)(H 2O)] 2}[Al(OH) 6Mo 6O 18] 3·33H 2O ( 4), were isolated by conventional solution method, and crystal structures have been determined by single-crystal X-ray diffraction. Among them, compound 1 displays a discrete supramolecular structure, compound 2 shows a chainlike structure with chloro-copper complexes as counteranions, and compounds 3 and 4 are isomorphic and exhibit unique 3D open frameworks with lattice water molecules residing in the channels. The compounds 3 and 4 represent the first example of 3D organic–inorganic hybrid compounds in the TMs/2,2′-bpy/POMs system. Investigation of the reaction conditions reveals that the geometry and size of the anions together with its coordinating abilities to the metal centers have a decisive influence on both the composition and the dimensionality of the final compounds.

Hydrothermal assembly and luminescence property of lanthanide-containing Anderson polyoxometalates

Two compounds, {[Sm(H 2O) 5] 2(TeMo 6O 24)}·6H 2O ( 1) and {[Eu(H 2O) 7] 2 (TeMo 6O 24)}·5H 2O ( 2) have been synthesized by hydrothermal reactions and characterized by elemental analyses, IR spectra, thermal stability analyses, X-ray powder diffraction, and single-crystal X-ray diffraction. Compound 1 represents the first example of a 2D layer architecture constructed from Anderson-type polyoxoanions [TeMo 6O 24] 6− and rare-earth ions Ln 3+. Compound 2 displays a 1D chain structure built up of alternating Anderson-type polyoxoanions [TeMo 6O 24] 6− and rare-earth ions Eu 3+ along the c-axis. Luminescence measurement of 2 exhibits typical red fluorescent emission of the Eu 3+ ion at room temperature. Furthermore, the emission is intense enough to be observed macroscopically under UV irradiation (365 nm).

Self-assembly of polyoxometalate clusters and metal–organic coordination fragments into 1D homochiral chains

A pair of enantiomerically pure polyoxometalates, (C 4NH 7O 4)[Na 2( l-C 4H 8N 2O 3) 2(H 2O) 9Zn] 2[CrMo 6H 6O 24] 2 · 7H 2O ( l- 1), and (C 4NH 7O 4)[Na 2( d-C 4H 8N 2O 3) 2(H 2O) 9Zn] 2[CrMo 6H 6O 24] 2 · 7H 2O ( d- 1), have been synthesized for the first time and characterized by elemental analyses, IR, TG, UV and single crystal X-ray diffraction. l- 1 and d- 1 are enantiomers and crystallize in the chiral space group P2 12 12. To our best knowledge, they represent the first examples of 1D homochiral polyoxometalate compounds constructed from Anderson-type polyoxoanions.

Synthesis and characterization of a novel Anderson-type tungstotellurate decorated by transition metal complexes: [Na(H2O)3]2[{Cu(2,2′-bipy)2}2(TeW6O24)] · 4H2O

A novel organic–inorganic hybrid tungstotellurate [Na(H2O)3]2[{Cu(2,2′-bipy)2}2(TeW6O24)] · 4H2O, has been synthesized and characterized by elemental analyses, IR spectra, TG analyses, and single-crystal X-ray diffraction. The saturated Anderson-type polyoxoanions are covalently bonded with two [Cu(2,2′-bipy)2]2+, and linked by Na+ into an infinite one-dimensional chain. Furthermore, the three-dimensional supramolecular architectures are formed by π–π stacking interactions of the 2,2′-bipyridine groups between adjacent layers and the hydrogen-bonding interactions respectively.

Organic−Inorganic Hybrids Constructed of Anderson-Type Polyoxoanions and Oxalato-Bridged Dinuclear Copper Complexes

Two novel organic-inorganic hybrid compounds based on Anderson-type polyoxoanions, [Cu2(bpy)2(mu-ox)][Al(OH)7Mo6O17] (1) and [Cu2(bpy)2(mu-ox)][Cr(OH)7Mo6O17] (2), have been synthesized and characterized by elemental analyses, IR, and X-ray powder diffraction. The crystal structures of 1 and 2 have been established by single-crystal X-ray diffraction, which reveals the presence of 1D chains constructed of alternating Anderson-type polyoxoanions and oxalato-bridged dinuclear copper complexes for both compounds and extensive hydrogen bonding that plays an important role in the formation of the 3D supramolecular network structures of 1 and 2. To elucidate the electronic properties and magnetic properties of the metal ions (Cu2+ or Cu2+ and Cr3+), EPR studies and magnetic susceptibility studies have been performed, respectively. The results are consistent with the structural feature of these compounds.

Synthesis and characterization of a new dimeric polyoxometalate based on Anderson-type polyoxoanions and a trinuclear lanthanide coordination complex

An unusual compound, H5[(C6NO2H4)4(H2O)15Nd3][IMo6O24]2·13.5H2O (1) has been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), and single crystal X-ray diffraction. Compound 1 consists of two [IMo6O24]5− units joined by a trinuclear neodymium-pyridine-4-carboxylic acid complex, resulting in a dimeric polyoxometalate, which further interact via weak intermolecular interactions to form a three-dimensional supramolecular framework with channels. To the best of our knowledge, no analogous dimeric polyoxometalate structure composed of an Anderson-type polyoxometalate has been reported in the literature.

Synthesis and characterization of two new extended structures based on Anderson-type polyoxoanions

Two new chain-like polymers, (C 6H 5NO 2) 2Na 2[(C 6H 5NO 2) 2NaCrMo 6H 6O 24] 1 and (C 6H 5NO 2) 2[(H 2O) 6DyCrMo 6H 6O 24]·4H 2O 2, have been synthesized and characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction. Compound 1 is built up of [CrMo 6H 6O 24] 3− cluster as the structural motif covalently linked by sodium-pyridine-3-carboxylic acid fragments to yield unprecedented one-dimensional chains, which are further in close contact forming a three-dimensional supramolecular framework via extensive hydrogen-bonding interactions among polyoxoanions, coordinated pyridine-3-carboxylic acid ligands and dissociated pyridine-3-carboxylic acid molecules. Compound 2 exhibits one-dimensional chain structure constructed from [CrMo 6H 6O 24] 3− building blocks and dysprosium cations, and adjacent chains are further pillared by free pyridine-4-carboxylic acid molecules to form an unusual two-dimensional supramolecular layer via hydrogen-bonding interactions.

Organic–inorganic hybrids with three-dimensional supramolecular channels based on Anderson type polyoxoanions

Two unusual compounds, (C 6H 5NO 2) 2[La(H 2O) 7][CrMo 6H 6O 24]·10.5H 2O 1 and (C 2H 5NO 2) 2[Nd(H 2O) 5][CrMo 6H 6O 24]·10H 2O 2, have been synthesized and characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction. Compound 1 is made up of supramolecular sheets of [Cr(OH) 6Mo 6O 18] 3− polyoxoanion-supported lanthanum complexes pillared by individual [Cr(OH) 6Mo 6O 18] 3− clusters via weak intermolecular interactions forming a three-dimensional microporous framework with two types of channels, and the ‘guest’ water molecules reside in the channels. Compound 2 also exhibits a new three-dimensional supramolecular network with one-dimensional sandglass-like channels based on the extensive hydrogen-bonding interactions between the [Cr(OH) 6Mo 6O 18] 3− polyoxoanions and neodymium–glycine coordination complexes.

Self-assembly of a novel 3D open framework from Anderson-type polyoxoanions

A new polyoxoanion-based compound, Na 4[Pr(H 2O) 5] 2[IMo 6O 24] 2 · 7H 2O ( 1), has been synthesized and characterized by elemental analyses, IR, XPS, TG, and single crystal X-ray diffraction. Compound 1 possesses a unique three-dimensional open framework composed of [IMo 6O 24] 5− polyoxoanions covalently linked by praseodymium cations, containing “guest” sodium ions and water molecules in the rectangular channels.

A novel chain-like polymer constructed from heteropolyanions covalently linked by lanthanide cations: (C5H9NO2)2[La(H2O)7CrMo6H6O24] · 11H2O (Proline=C5H9NO2)

A new polymer (C5H9NO2)2[La(H2O)7CrMo6H6O24]·11H2O (1), has been synthesized and structurally characterized. Compound 1 exhibits a novel one-dimensional (1-D) chain-like structure consisting of Anderson-type polyoxoanions hexamolybdochromate [CrMo6H6O24]3− covalently linked by hydrated La3+ ions, furthermore pseudo-2-D layers can be formed owing to the strong (La)OH2⋯O hydrogen bonds among adjacent chains.