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A monomeric phosphotungstate-supported rhenium carbonyl derivative, [N(CH3)4]6H4[P2W17O62{Re(CO)3}2]·25H2O (1), has been synthesized in a conventional solution system and structurally characterized by single crystal X-ray diffraction crystallography, IR spectroscopy, thermogravimetric (TG) analyses, X-ray powder diffraction (XRPD), and electrospray ionization mass spectrometry (ESI-MS). To our knowledge, this is the first time that the {Re2} fragment existing in the polyoxoanion has been observed in polyoxometalate-supported metal carbonyl derivatives. Moreover, UV-vis spectroscopy was employed to elucidate the stability of the polyoxoanion, and its electrochemical properties were also investigated. In particular, complex 1 could act as an efficient homogeneous catalyst for selective oxidation of thiophenes. For example, dibenzothiophene (DBT) undergoes up to 99% conversion and 99% sulfone selectivity in acetonitrile with 30% H2O2 as an oxidant. [ABSTRACT FROM AUTHOR]

Abstract: An acetate‐bridged Ru‐substituted arsenotungstate [H2N(CH3)2]14[As4W40O140{Ru2(CH3COO)}2]⋅22 H2O (1) has been synthesized and structurally characterized. Four Ru atoms occupy the respective lacunary S2 sites of the crown‐shaped polyanion [As4W40O140]28−, and each Ru atom is coordinated by one As atom and five μ2‐O atoms, comprising four from the S2 site and one from the acetate ligand. To the best of our knowledge, this coordination of the Ru atom, with an Ru−As bond length of 2.377(3)–2.387(3) Å, is unprecedented in polyoxometalate (POM) chemistry. Notably, 1 exhibits high efficiency, excellent selectivity, and good recyclability for the oxidation of sulfides with hydrogen peroxide (H2O2). Catalytic oxidation of various sulfides in the presence of 1 gives superior conversion and selectivity for sulfones in acetonitrile, whereas sulfoxides are obtained in methanol. [ABSTRACT FROM AUTHOR]

A 1-D infinite helical chain-like organic–inorganic hybrid arsenotungstate Na4H8[{Pr(H2O)2}2{As2W19O68}{WO2(mal)}2]·24H2O (mal = malate) (1) was prepared, which was characterized by elemental analyses, thermogravimetric (TG) analyses, IR spectroscopy, powder X-ray diffraction (PXRD) and X-ray single-crystal diffraction. Structural characterization revealed that 1 comprises the organo-functionalized [{As2W19O68}{WO2(mal)}2]18− polyanions hinged together by the Pr3+ ions forming a 1-D infinite helical chain-like architecture. The malate ligand may play a vital role to stabilize the structure of 1 by the formation of the five-membered W–O–C–C–O chelate ring. Solid state photoluminescence reveals that 1 features excitation wavelength-dependent emission properties, achieving a reversible emission color switching simply via changing the excitation wavelength. Time-resolved emission spectroscopy (TRES) indicates that the photoexcitation O → M ligand to metal charge transfer (LMCT) of arsenotungstate fragments can sensitize the Pr3+ ions through intramolecular energy transitions in 1. [ABSTRACT FROM AUTHOR]

A novel isopentatungstate-supported metal carbonyl derivative KH[(CH3)4N]3{[Re(CO)3]4[(μ2-OH)(μ3-O)(W5O18)]}·6H2O (1) has been synthesized and characterized. Compound 1 represents the second example of isopolyoxotungstate-supported metal carbonyl derivative. The catalysis of 1 for alkene epoxidation with H2O2 was investigated, and was found to efficiently catalyze the epoxidation of cyclooctene with high conversion (98.9%) and excellent selectivity (99%). Furthermore, the solution behavior of the polyanion 1 was also explored using electrospray ionization mass spectrometry. [ABSTRACT FROM AUTHOR]

A new compound H[NaCuCl(HO)(B- α-AsWO)] 24HO ( 1) is synthetized by the reaction of the CuCl 2HO and Na[NaAsWO] 60HO in aqueous solution, which is constructed from a {CuNa} hexagon moiety sandwiched by two trilacunary [B- α-AsWO] units. The structure is determined by single-crystal X-ray diffraction technique and further characterized by IR spectroscopy. Single-crystal X-ray diffraction analysis reveals that 1 is built by two trilacunary [B- α-AsWO] units incorporating a {CuNa} hexagon moiety and further linked to each other to form an infinitely extended 2-D network via Cu-O-W bridges. Notably, magnetic measurement demonstrates that the occurrence of intramolecular ferromagnetic Cu-Cu interactions within {CuNa} hexagon moiety. [ABSTRACT FROM AUTHOR]

An organic–inorganic coplanar-shaped hexa-CuII sandwiched hybrid, (H2en){[Cu(en)2]2[Cu2(en)2Cu4(H2O)2](B-α-AsW9O34)2} · 5H2O (en = ethylenediamine) (1), has been synthesized via hydrothermal method and further characterized by IR spectroscopy, thermogravimetric analysis, and X-ray single-crystal diffraction. Single-crystal X-ray diffraction analysis shows that 1 contains an organic–inorganic hybrid polyoxoanion {Cu2(en)2Cu4(H2O)2(B-α-AsW9O34)2}6−, which can be described as a coplanar-shaped hexa-CuII cluster sandwiched by two trivacant [B-α-AsW9O34]9− fragments. Complex 1 represents a rare organic–inorganic coplanar-shaped hexa-CuII cluster sandwiched arsenotungstate. Magnetic susceptibility measurements indicate that 1 demonstrates ferromagnetic coupling interactions within the CuII centers. [ABSTRACT FROM PUBLISHER]

Two new organic-inorganic composite sandwich-type arsenotungstates [H2dap]6H8[Ni4(H2O)2(B-α-AsW9O34)2]2 · 33H2O (1) and {[Ni(dap)2(H2O)]2[Ni(dap)2]2[Ni4(Hdap)2(B-α-AsW9O34)2]} · 4H2O (2) (dap = 1,2-diaminopropane) have been hydrothermally synthesized by reaction of Na8[A-α-HAsW9O34] · 11H2O with NiCl2 · 6H2O in the presence of 1,2-diaminopropane and characterized by elemental analysis, IR spectra, X-ray single-crystal diffraction, and thermogravimetric analysis. 1 crystallizes in the triclinic P1 space group with a = 16.351(6) Å, b = 16.423(6) Å, c = 19.894(7) Å, α = 110.630(6)°, β = 92.684(7)°, γ =104.946(7)°, V = 4774(3) Å3, Z = 1, GOOF = 1.033, R1 = 0.0517, wR2 = 0.1086. 2 also crystallizes in the triclinic P1 space group with a = 13.305(4) Å, b = 13.882(4) Å, c = 17.031(5) Å, α = 68.109(5)°, β = 71.511(4)°, γ = 88.407(5)°, V = 2753.5(14) Å3, Z = 1, GOOF = 1.051, R1 = 0.0491, wR2 = 0.1150. Notably, 1 is a discrete structure, composed of two tetra-NiII substituted sandwich-type polyoxoanions [Ni4(H2O)2(B-α-AsW9O34)2]10- with different spatial orientation, whereas 2 displays a organic-inorganic composite 2-D sheet architecture constructed by tetra-NiII sandwiched [Ni4(H2O)2(B-α-AsW9O34)2]10- units by means of [Ni(dap)2]2+ bridges. Some previously reported transition-metal-substituted sandwich-type polyoxotungstates have been summarized. [ABSTRACT FROM AUTHOR]

Two new hybrid Dawson-based polyoxotungstates, [Mn(2,2'-bipy)3]H2[Mn(2,2'-bipy)2][P2W18O62] (1) and [Co(H2biim)3)]2H2[P2W18O62] · 8H2O (2) (2,2'-bipy = 2,2'-bipyridine, H2biim = 2,2'-biimdazole), have been prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, thermogravimetric analyses (TGA), X-ray photoelectron spectroscopy (XPS), and photoluminescence spectra. Compound 1 is a 1-D zigzag chain constructed from alternate Dawson-type heteropolyanions [α-P2W18O62]6- and metal coordination cations [Mn(2,2'-bipy)2]2+, in which the 1-D chains are extended into a 3-D framework through C-H ··· π and π-π stacking interactions. Compound 2 is a discrete structure consisting of [α-P2W18O62]6- and two [Co(H2biim)3)]2+ cations, forming a 3-D supramolecular framework via N-H ··· O hydrogen bonds and C-H ··· π interactions. Photoluminescence properties of 1 and 2 have been investigated at room temperature. [ABSTRACT FROM AUTHOR]

Two new polyoxometalate compounds based on the lacunary Keggin anion [α-GeW11O39]8- and the rare earth cation PrIII, [(CH3)4N]2.25H1.25[Pr1.5(GeW11O39)(H2O)5.75] · 1.25H2O (1) and [Pr0.5(H2O)2.25]H0.5[Pr2(GeW11O39)(DMSO)2(H2O)8] · 5.75H2O (2), have been synthesized and characterized by elemental analysis, inductively coupled plasma (ICP) analysis, IR and UV spectroscopy, and single-crystal X-ray diffraction. The solid-state structure of 1 consists of one-dimensional zig-zag chains built of [α-GeW11O39]8- anions connected by Pr3+. In 2, DMSO (DMSO = dimethyl sulfoxide) leads to a double-parallel chainlike structure constructed by two linear wires {[Pr(GeW11O39)(DMSO)(H2O)2]5-}n linked by Pr3+ coordination cations. [ABSTRACT FROM AUTHOR]

Abstract: Two arsenotungstates based on Dawson polyanions, 1-D chain H8[{CuI(en)2}4{CuI(2,2′-bipy)(H2O)}2{CuI(2,2′-bipy)(As2W17CuO61)}2]·4H2O (1) and 2-D network [Cu(2,2′-bipy)3]2 [(As2W18O62)Na4(H2O)11]2 ·7H2O (2) (2,2′-bipy=2,2′-bipyridine), have been hydrothermally synthesized and characterized by elemental analyses, IR, ESR, TG-DTA and single-crystal X-ray diffraction. Compound 1 crystallizes in triclinic system, space group P−1, a =11.640(3), b =13.177(3), c =31.143(7)Å, α =87.43(0)°, β =84.47(0)°, γ =68.02(0)°. Compound 2 crystallizes in hexagonal system, space group P−6 2c, with a =12.9175(7), c =28.371(3)Å. The structure of 1 represents the first 1-D chain consisted of oxo-bridged Wells–Dawson arsenotungstate anions. The compound 2 is the first 2-D sodium arsenotungstate, whose building units [(As2W18O62)(H2O)8Na2]4− were connected to neighboring units via [Na2(H2O)3]2+ bridging groups. [Copyright &y& Elsevier]

Two novel metatungstate compounds [Hdmpy] 4 H 2 [H 2 W 12 O 40 ]·4H 2 O (dmpy = 2,6-dimethyl pyridine) ( 1 ) and [Hpy] 4 H 2 [H 2 W 12 O 40 ] (py = pyridine) ( 2 ) have been synthesized by rational reaction, rather than hydrothermal or electrosynthetic reaction, of sodium tungstate dihydrate with 2,6-dimethyl pyridine and pyridine, respectively and characterized by IR and electronic spectroscopies, thermal behavior and electrochemistry. X-ray single-crystal structural analyses indicate that both structures consist of close-packed arrangements of the almost spherical Keggin-type anion [H 2 W 12 O 40 ] 6- with protonated 2,6-dimethyl pyridine or pyridine molecules filling the gap of the polyanions and interacting with the metatungstate anions in the mode of W-O···H-N or W-O···H-C, giving a two-dimensional network structure. The TG-DTA curves of 1 show that weight loss is divided into two stages, and reveal that the framework of the polyanion in 1 begins to decompose at 613°C. Electrochemical study shows that Compound 1 exhibits two chemically quasi-reversible one-electron reduction processes in aqueous solution (0.5 M NaCl + HCl) in the pH range 4-7. [ABSTRACT FROM AUTHOR]

Correction for 'A new phosphotungstate-supported rhenium carbonyl derivative: synthesis, characterization and catalytic selective oxidation of thiophenes' by Jingkun Lu et al., CrystEngComm, 2019, 21, 7322–7328. [ABSTRACT FROM AUTHOR]

Twonovel 1D copper-bridged tetrahedral polyoxometalate nanoclusterswith tetrameric rare-earth cores and germanotungstate vertexes, Na3H7[Cu(en)2]5[Cu(en)2(H2O)]2[RE4Ge4W46O164(H2O)3]·nH2O (RE = GdIII, n= 25 for 1; RE = YIII, n= 23 for 2; en = ethylenediamine),have been hydrothermally synthesized and structurally characterizedby elemental analyses, IR spectra, thermogravimetric analysis (TGA),and single-crystal X-ray diffraction. The most prominent structuralfeature of 1and 2consists of unprecedentedtetrahedral RE-substituted germanotungstate nanoclusters {[(α-GeW11O39RE)2(μ3-WO4)(α-GeW11O39RE(H2O))](μ4-WO4)[α-GeW11O39RE(H2O)2]}24–, in which four mono-REIII-substituted Keggin [α-GeW11O39RE(H2O)n]5–(n= 0, 1, 2) moieties arecombined together with the aid of two WO42–connectors. What’s more interesting is that adjacent tetrahedralnanoclusters are interconnected with each other via [Cu(en)2]2+bridges, forming a 1D extended chain architecture.To our knowledge, 1and 2are the firstpolyoxometalate-based Cu–RE containing 1D chain constructedfrom tetrahedral RE-substituted germanotungstate nanoclusters andcopper–organic bridges. Furthermore, the solid-state electrochemicaland electrocatalytic properties of 1and 2have been carried out in 0.5 mol·L–1Na2SO4+ H2SO4aqueous solutionby entrapping them in a carbon paste electrode. 1and 2display apparent electrocatalytic activities for the nitriteand bromate reduction. [ABSTRACT FROM AUTHOR]

A series of organic–inorganic hybrid lacunaryKeggin silicotungstate3d-4f heterometallic derivatives, {[Cu (en)2]1.5Ln[(α-SiW11O39)2]}220–[Ln = GdIIIfor 1,TbIIIfor 2, DyIIIfor 3, ErIIIfor 4, LuIIIfor 5], {[Cu(en)2]1.5Ln[(α-SiW11O39)]}2–[Ln = LaIIIfor 6, CeIII, for 7] and {[Cu(en)2(H2O)][Cu(en)2]nLn[(α-SiW11O39)2]}m−[(Ln, n, m) = (PrIII, 2, 7) for 8, (SmIII, 3, 5) for 9] (en = ethylenediamine) havebeen successfully synthesized under hydrothermal conditions and furthercharacterized by elemental analyses, inductively coupled plasma atomicemission spectrometry (ICP-AES) analyses, X-ray powder diffraction(XRPD), IR spectra, thermogravimetric (TG) analyses, and single-crystalX-ray diffraction. The common features of 1–5and 8–9are that they allconsist of a sandwich-type [Ln(α-SiW11O39)2]13–polyoxoanion, whereas both 6and 7consist of the unusual 1:1 [Ln(α-SiW11O39)]5–units and [Cu(en)2]2犊⭶⧚똪 cations. 1–5show dimeric structures, and 6–9display unprecedented three-dimensional (3D) frameworks,representing the first 3D 3d-4f heterometallic silicotungstates. Thefeatures of 6and 7are that the componentsare closely packed along the 21screw axis to generatescarce 5-connected network structures with the Schläfli symbolof (48·62), while 8and 9exhibit the 4-connected (66) topology and 6-connected(48·54·63) topologystructures, respectively. Furthermore, 2, 3, and 9manifest apparent fluorescence signals, whichcan be assigned to the characteristic emissions of TbIII, DyIII, and SmIIIcations, respectively. [ABSTRACT FROM AUTHOR]

Abstract: A S-shaped multi-iron substituted arsenotungstate [enH2]2[(α-H2AsVW6O26)Fe3(H2O)(B-α-H4AsVW9O34)]2[Fe]2·8H2O (1) (en=ethylenediamine) has been prepared by reaction of K14[As2 IIIW19O67(H2O)]·nH2O with Fe2(SO4)3·xH2O under hydrothermal conditions and structurally characterized by elemental analyses, IR spectra, UV spectra, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. The skeleton of 1 consists of two asymmetric sandwich-type subunits [(α-H2AsVW6O26)Fe3(H2O)(B-α-H4AsVW9O34)]5− linked by a di-FeIII cluster. Moreover, magnetic susceptibility measurements demonstrate that 1 indicates the antiferromagnetic coupling interactions within FeIII centers with the best-fitting set of parameters of J 1=−7.07cm−1, J 2=−0.45cm−1 and g=2.05, which are generated by the addition of the expressions of the molar susceptibilities of two tri-FeIII clusters and one di-FeIII cluster derived from for spin pairs coupled through the isotropic exchange interactions. [Copyright &y& Elsevier]

Abstract: A new organic–inorganic hybrid nickel-substituted arsenotungstate [Na(H2O)3]2[Ni(H2O)6]2[Ni(H2O)5]{[Ni3(dap)(H2O)2]2(H2W4O16)}{(α-H2AsW6O26)[Ni6(OH)2(H2O)(dap)2](B-α-HAsW9O34)}2·7H2O (1) (dap=1,2-diaminopropane) has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Crystal data for 1: C18H144As4N12Na2Ni21O176W34, Mr=11174.92, triclinic, space group P-1, a =15.004(4)Å, b =16.357(5)Å, c =22.070(6)Å, α =80.458(5)°, β =79.291(5)°, γ =72.074(5)°, V =5030(3)Å3, Z =1, GOOF =1.007, R 1 =0.0703, wR 2 =0.1670. The skeleton of 1 is a centric nanoscale cluster and is composed of two asymmetric sandwich-type clusters {(α-H2AsW6O26)[Ni6(OH)2(H2O)(dap)2](B-α-AsW9O34)}7− linked by a symmetric cluster {[Ni3(dap)(H2O)2]2(H2W4O16)}6+. Notably, 1 is an interesting polyoxometalate containing the trivacant Keggin [B-α-AsW9O34]9−, hexavacant Keggin [α-AsW6O26]11− and tetrameric [W4O16]8− units. Magnetic measurements indicate that 1 shows the ferromagnetic interactions within NiII centers. [Copyright &y& Elsevier]

Abstract: A 65·8 CdSO4-like 3-D framework [Cu(en)2]3[α-AsW11NaO39]·2H2O (1) constructed by monosodium-substituted Keggin arsenotungstates and copper(II)-ethylenediamine complexes (en=ethylenediamine) has been synthesized by reaction of Na8[α-HAsW9O34]·11H2O, CuCl2·2H2O and ethylenediamine under hydrothermal conditions and structurally characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction. Crystal data for 1: C12H52AsCu3N12NaO41W11, monoclinic, Cc, a =20.409(9)Å, b =16.737(8)Å, c =16.561(7)Å, β =104.607(7)°, V =5474(4)Å3, T =296(2)K; Z =4, μ =24.860mm−1, GOOF =1.086, R 1 =0.0284, wR 2 =0.0759. To the best of our knowledge, 1 represents the first 65·8 CdSO4-like 3-D monovacant Keggin arsenotungstate derivative in polyoxometalate chemistry. [Copyright &y& Elsevier]

Abstract: An unprecedented 2-D organic–inorganic hybrid sandwich-type polyoxotungstate containing O-donor organic ligands [DMAH]4{[Mn(DMF)4]2[Mn4(DMF)2(α-B-HPW9O34)2]} (1) (DMA=dimethylamine, DMF=N,N-dimethylformamide) has been solvothermally synthesized and characterized by IR, UV spectra and X-ray single-crystal diffraction. The 2-D organic–inorganic hybrid network of 1 is built by tetra-MnII substituted sandwich-type polyoxotungstates [Mn4(DMF)2(α-B-HPW9O34)2]8− and [Mn(DMF)4]2+ cation bridges, which displays the common 2-D (4,4) topological net. It should be noted that the major difference between [Mn4(DMF)2(α-B-HPW9O34)2]8− in 1 and the reported [Mn4(H2O)2(α-B-PW9O34)2]10− is that two DMF ligands substitute two H2O ligands on the Mn4O16 unit located in the sandwich belt. Magnetic susceptibility measurement indicates the occurrence of antiferromagnetic coupling interaction within MnII ions. [Copyright &y& Elsevier]