Se-Rich Multinuclear Er-Containing Dawson-type Poly(selenotungstate).

A multinuclear Er-containing Dawson-type poly(selenotungstate) (poly(ST)) [HN(CH)]NaCsH [ErSeWO(HO)(SeWO)]·78HO () was made by the one-pot assembly with an excess SeO source in the reaction system. The polyoxoanion consists of an extremely rare ErSeWO(HO) ({ErSeW}) cluster core surrounded by six tetravacant Dawson-type SeWO ({SeW}) fragments, representing the most Se-containing Dawson-type structure so far. Notably, the {ErSeW} cluster exhibits an interesting trefoil-shaped configuration, formed by the condensation of a central ErSeO ({ErSe}) cage with three ErSeWO(HO) ({ErSeW}) clusters.

{SeO(OH)} Bridging Lanthanide-Containing Antimono-Seleno-Tungstates.

A series of new trigonal pyramidal {SeO(OH)} bridging lanthanide-containing antimono-seleno-tungstates [HN(CH)]NaCsH[LnSeWO(OH)(HO)(SbWO)(SeWO)(SeSbWO)]·32HO [Ln = Tb (), Dy (), Ho (), Er ()] have been prepared by the synthetic strategy of simultaneously using the antimonotungstate precursor and simple material in an acidic aqueous solution and structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR spectrometry, and thermogravimetric analysis. Their molecular structures contain an unprecedented hexameric polyoxoanion [LnSeWO(OH)(HO)(SbWO)(SeWO)(SeSbWO)] constituted by two equivalent trimeric subunits LnWO(HO)(SbWO)(SeWO)(SeSbWO) bridged via two μ-{SeO(OH)} linkers. Furthermore, the catalytic oxidation of various aromatic sulfides and sulfur mustard simulant 2-chloroethyl ethyl sulfide (CEES) by compound as the heterogeneous catalyst has been investigated, exhibiting high conversion and selectivity as well as good stability and recyclability.

{Ti} Cluster-Added Poly(polyoxometalate) Containing Mixed Trivacant Keggin and Dawson Fragments.

A new high-nuclear Ti-oxo-cluster-added poly(polyoxometalate) CsNaH[(Cs@TiO)@{(-α-SiWO) (PWO)}]·29HO () has been made by reacting two types of trivacant precursors with TiOSO under hydrothermal conditions. The polyoxoanion of contains one Keggin-type [-α-SiWO] and three Dawson-type [PWO] fragments that synergistically induce the Ti ions to aggregate at vacant sites, resulting in a large {Ti}-oxo-cluster cavity sealing a Cs ion. It is worth noting that the {Ti} cluster is built by three edge-shared TiO ({Ti}) cores and one corner-shared TiO ({Ti}) core bridged via 6 μ-O, which has never been seen before in polyoxometalate chemistry.

A Zr-added Dawson-type poly(polyoxometalate).

A novel Zr-added trimer, [HN(CH)]H[(ZrPWO)]·7HO (1), has been made under hydrothermal conditions, and contains the highest number of Zr centers in known Dawson-type poly(POM)s. A remarkable feature of this study is the first discovery of a new type of divacant [α-5,10-PWO] fragment, which assembles with Zr ions to form a cyclic trimer. Furthermore, 1 as a heterogeneous catalyst exhibits high activity for the selective oxidative degradation of a sulfur mustard simulant CEES.

High-Nuclear Ni-Substituted Poly(polyoxometalate) Containing an Anderson-like {Cs} Cluster.

A novel high-nuclear Ni-substituted poly(polyoxometalate) [poly(POM)], [HN(CH)]NaCsH[(Cs(HO))@{(PO)-@(Ni(OH)(WO))@(-α-PWO)}]·30HO (), has been successfully developed and structurally characterized. The polyoxoanion of can be viewed as a unique huge sandwich structure made of an unprecedented Cs(HO) ({Cs}) cluster core encapsulated by two trimeric [(PO)@(Ni(OH)(WO))@(-α-PWO)] subunits, in which the {Cs} cluster presents an interesting Anderson-like arrangement and is the first example of a classical POM configuration based on the alkali metal cluster in the POM chemistry. The polyoxoanion can also be described as an unusual [(Cs(HO))@{(PO)@(Ni(OH)(WO))}] cluster packaged by six {PW} fragments.

{Ti}/{Ti} Wheel Cluster Substituted Silicotungstate Aggregates.

Two novel Ti-oxo wheel cluster substituted silicotungstates (STs) [HN(CH)]H[TiO(SiWO)]·11HO () and [HN(CH)]H[TiO(SiWO)(SiWO)]·14HO () have been made by hydrothermal reactions. The polyoxoanion of is a ring-shaped trimer where a TiO ({Ti}) wheel cluster is encapsulated by three divacant [SiWO] (SiWO) fragments. However, is built by two divacant SiWO units and two rare trivacant [SiWO] (SiWO) fragments and further installs an unprecedented TiO ({Ti}) double-wheel cluster.

A {TiW}-Cluster-Substituted Polyoxotungstate: Synthesis, Structure, and Catalytic Oxidation Properties.

A novel Ti-W-O-cluster-substituted tungstoantimonate (TA), [HN(CH)]NaH[{TiWO(OH)(HO)}(B-α-SbWO)]·20HO (), has been made by hydrothermal reactions of trivacant [B-α-SbWO] units, Ti cations, and WO anions in the presence of [HN(CH)]·Cl and structurally characterized. Intriguingly, the polyoxoanion of is constructed from three [B-α-SbWO] units and a previously unobserved decanuclear heterometallic Ti-W-O cluster [TiWO(OH)(HO)] ({TiW}) that is comprised of an octahedral [TiWO(HO)] cluster and an edge-sharing [WO(OH)] fragment via six W-O-Ti/W linkers. Furthermore, studies on the catalytic oxidation properties reveal that possesses good catalytic activity toward the oxidation reactions of various sulfides and cyclooctene based on the environmentally friendly oxidant HO.

A μ-AsO-Bridging Hexadecanuclear Ni-Substituted Polyoxotungstate.

A novel tetrahedral μ-AsO-bridging hexadecanuclear Ni-substituted silicotungstate (ST) NaH[(AsO){Ni(OH)(HO)(CO)(SiWO)}]·60HO () was made by the reactions of trivacant [-α-SiWO] ({SiW}) units with Ni cations and NaAsO·12HO and characterized by IR spectrometry, elemental analysis, thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD). contains a novel polyoxoanion [(AsO){Ni(OH)(HO)(CO)(SiWO)}] built by four trivacant Keggin [SiWO] fragments linked through an unprecedented [(AsO){Ni(OH)(HO)(CO)}] cluster, where the tetrahedral AsO acts as an exclusively μ-bridging unit to link multiple Ni centers; such a connection mode appears for the first time in polyoxometalate chemistry. Furthermore, the electrochemical and catalytic oxidation properties of compound have been investigated.

Three Zr(IV)-Substituted Polyoxotungstate Aggregates: Structural Transformation from Tungstoantimonate to Tungstophosphate Induced by pH.

Three novel Zr-substituted polyoxotungstate aggregates [HN(CH)]NaH[ZrSbO(-α-PWO)]·16HO (), [HN(CH)]H[ZrSb(OH)O(-α-PWO)(-α-PWO)]·33HO (), and [HN(CH)]NaH[ZrWSbPO(OH)(-α-SbWO)]·53HO () have been made in hydrothermal reactions of the [-α-SbWO] precursor with Zr cations and PO anions in the presence of dimethylamine hydrochloride and sodium acetate buffer (pH = 4.8) and structurally characterized. Different pH values induce structural transformation from tungstoantimonate (TA) to tungstophosphate (TP).

Nonanuclear Heterometal Five-Layer Sandwich-Type Polyoxometalate.

A new nonanuclear heterometal five-layer sandwich silicotungstate [HN(CH)]HNaK{[NaMnO(OAc)][SiWO]}·34HO () has been made under hydrothermal reactions of MnCl·4HO, KMnO, trivacant [-α-SiWO] {SiW} fragment, and [HN(CH)]·Cl in NaOAc-HOAc buffer (pH = 4.8). The polyoxoanion of is a sandwich architecture, in which the nonanuclear heterometal cluster [NaMnO(OAc)] made of two triangular pyramid clusters [MnO(OAc)] {Mn} via a hexacoordinate antitrigonal prism Na linkage is encapsulated by two trivacant fragments of {SiW}.

A new octa-Mn-substituted poly(polyoxotungstate).

A novel octa-Mn-substituted silicotungstate (ST) [HN(CH)]HNa{[K(HO)WO][SiMnWO]}[SiMnWO]·27HO (1) has been made by the hydrothermal reaction of the trivacant [A-α-SiWO] ({SiW}) building block with Mn and Mn cations in the presence of dimethylamine hydrochloride and systematically characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) and single crystal X-ray diffraction. 1 is a tetrameric cluster formed by a hexa-Mn substituted cyclic trimeric {[K(HO)WO][SiMnWO]} unit and a {SiMnWO} fragment via two W-O-Mn linkers. Furthermore, its electrochemistry, thermal stability and magnetic properties have been studied.

Two Ce-Substituted Selenotungstates Regulated by N, N-Dimethylethanolamine and Dimethylamine Hydrochloride.

Two multi-Ce-substituted selenotungstates (STs), [HDMEA][HN(CH)]HNa[Ce(HO)(DMEA)WO(α-SeWO)]·26HO (1) and [HN(CH)]HNa[CeWO(HO)(α-SeWO)]·63HO (2), were prepared by the one-pot approach of sodium tungstate, sodium selenite, and lanthanide nitrate in an acidic water solution in the presence of N, N-dimethylethanolamine (DMEA) or dimethylamine hydrochloride (DMAHC). 1 was obained in the presence of DMEA, whereas 2 was synthesized in the presence of DMAHC. The trimeric polyoxoanion of 1 contains an unusual V-shaped [SeWO] group embracing a prominent heterometal oxide fragment, [Ce(HO)(DMEA)WO], and the hexameric polyoxoanion of 2 is constructed from two equivalent trimeric [CeWO(HO)(SeWO)] subunits through two -O-W-O-Ce-O- linkages.

Syntheses, Structures, and Electrochemical Properties of Three New Acetate-Functionalized Zirconium-Substituted Germanotungstates: From Dimer to Tetramer.

Under hydrothermal conditions, three new acetate-functionalized zirconium-substituted polyoxometalates, HNa[Na(HO)][Zr(μ-O)(OH)(OAc)(α-GeWO)]·32HO (1), HKNa[Zr(μ-O)(OH)(OAc)(HO)(β-GeWO)]·20HO (2), HKNa[{Zr(μ-OH)(OH)}@{Zr(OAc)(α-GeWO)}]·22HO (3), were synthesized and characterized. In 1, the sandwiched dimer [Zr(μ-O)(OH)(OAc)(α-GeWO)] was linked to a hexameric [Na(HO)] cluster to form a 1D chain. In 2, the trimer was constructed from three [β-GeWO] units and a new [ZrO(OH)(OAc)(HO)] cluster.

A new tetra-Zr(iv)-substituted polyoxotungstate aggregate.

A new tetra-Zr-substituted tungstophosphate (TP), [H2N(CH3)2]6Na6H8{Zr2[SbP2W4(OH)2O21][α2-PW10O38]}2·50H2O (1), has been made by the hydrothermal reaction of the [B-α-SbW9O33]9- building block with Zr4+ cations and PO43- anions in the presence of dimethylamine hydrochloride and NaOAc-HOAc (pH = 4.8), and further characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), 31P NMR spectroscopy and single-crystal X-ray diffraction. 1 is a toroidal structure formed by two divacant [α2-PW10O38]11- units and two [SbP2W4(OH)2O21]7- fragments linked by four Zr4+ cations.

Unprecedented Selenium and Lanthanide Simultaneously Bridging Selenotungstate Aggregates Stabilized by Four Tetra-vacant Dawson-like {Se W } Units.

In the presence of the larger [H N(CH ) ] and K counter cations as structure-stabilizing agents, a class of unprecedented selenium and lanthanide (Ln) simultaneously bridging tetra-vacant Dawson-like selenotungstate aggregates [H N(CH ) ] Na K H {[Ln W Se O (H O) ](Se W O ) } ⋅60 H O [Ln=Tb (1), Dy (2), Ho (3), Er (4), Tm (5), Yb (6)] have been obtained by the one-pot assembly reaction of Na WO ⋅2 H O, Ln(NO ) ⋅6 H O, and Na SeO under moderately acidic aqueous conditions and the complexes were structurally characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. It should be noted that the appropriate molar ratio of Se/W is extremely important in the formation of 1-6 and can effectively ameliorate the yield of 1-6. Moreover, dimethylamine hydrochloride is also indispensable and plays a considerably important role in improving the solubility of Ln ions and stabilizing the structures of 1-6.

Structural Transformation from Dimerization to Tetramerization of Serine-Decorated Rare-Earth-Incorporated Arsenotungstates Induced by the Usage of Rare-Earth Salts.

Three types of serine-decorated rare- earth-containing arsenotungstate [H N(CH ) ] NaH[RE W O (H O) (Ser) (B-α-AsW O ) ]⋅30 H O (RE =Eu , Gd , Tb , Dy , Ho , Er , Tm , Yb , and Y ; 1), [H N(CH ) ] Na RE H [RE W O (H O) (OH) (Ser) (B-α-AsW O ) ]⋅n H O (RE =Tb , x=1, y=2, n=36; RE =Dy , Ho , Er , Yb , Y , x=0, y=0, n=38; RE = Tm , x=1, y=0, n=38; Ser=serine; 2), and [H N(CH ) ] Na RE H [RE W O (H O) (OH) (Ser) (B-α-AsW O ) ]⋅Cl ⋅n H O (RE =Ce , Pr , x=1, y=0, n=65; RE =Nd , Sm , x=0, y=0, n=65; RE =Eu , Gd , x=1, y=2, n=45; 3) were synthesized with the participation of the organic solubilizers dimethylamine hydrochloride and l-serine and were structurally characterized. The use of different amounts of rare-earth salts results in the structural transformation from dimerization to tetramerization of types 1-3. Type 1 is a dimeric sandwich-type assembly of a dual-Ser-participating [RE W O (H O) (Ser) ] entity sandwiched by two [B-α-AsW O ] moieties, whereas types 2 and 3 have a tetrameric square structure formed by four [B-α-AsW O ] moieties that anchor a dual/tetra- Ser-participating [RE W O (H O) (OH) (Ser) ] or [RE W O (H O) (OH) (Ser) ] core.

Lanthanide-Connecting and Lone-Electron-Pair Active Trigonal-Pyramidal-AsO3 Inducing Nanosized Poly(polyoxotungstate) Aggregates and Their Anticancer Activities.

By virtue of the stereochemical effect of the lone-electron pair located on the trigonal-pyramidal-AsO3 groups and the one-pot self-assembly strategy in the conventional aqueous solution, a series of novel lanthanide-bridging and lone-electron-pair active trigonal-pyramidal-AsO3 inducing nanosized poly(polyoxotungstate) aggregates [H2N(CH3)2]6 Na24H16{[Ln10W16(H2O)30O50](B-α-AsW9O33)8}·97H2O [Ln = Eu(III) (1), Sm(III) (2), Gd(III) (3), Tb(III) (4), Dy(III) (5), Ho(III) (6), Er(III) (7), Tm(III) (8)] were prepared and further characterized by elemental analyses, IR spectra, UV spectra, thermogravimetric (TG) analyses and single-crystal X-ray diffraction. The most remarkable structural feature is that the polyanionic skeleton of {[Ln10W16(H2O)30O50](B-α-AsW9O33)8}(46-) is constructed from eight trivacant Keggin [B-α-AsW9O33](9-) fragments through ten Ln centers and sixteen bridging W atoms in the participation of fifty extraneous oxygen atoms. Notably, 4 and 8 can be stable in the aqueous solution not only for eight days but also in the range of pH = 3.