Abstract The development of visible‐light‐induced photocatalysts for chemoselective functional group transformations has received considerable attention. Polyoxometalates (POMs) are potential materials efficient because their properties can be precisely tuned by changing constituent elements and structures the introduction additional metal cations. Furthermore, they thermally oxidatively more stable than frequently utilized organometallic complexes. visible‐light‐responsive tetranuclear...

An Ag4 diamond is encapsulated by silicotungstate ligands in TBA8[Ag4(DMSO)2(γ-H2SiW10O36)2]⋅2 DMSO⋅2 H2O (Ag4; DMSO=dimethyl sulfoxide, TBA=tetra-n-butylammonium), which was obtained reaction of TBA4H4[γ-SiW10O36] with AgOAc an organic medium. Polyoxometalate (see picture) selectively catalyzes hydrolytic oxidation various silanes to the corresponding silanols high yields (72–96 %).

An yttrium-pillared silicotungstate dimer (see picture) catalyzes the cyanosilylation of structurally diverse ketones and aldehydes with trimethylsilyl cyanide (TMSCN). The reactions proceed selectively afford corresponding cyanohydrin ethers. catalytic performance is significant, in particular for aldehydes, a turnover number 18 000 frequency 540 h−1 n-hexanal. Detailed facts importance to specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not...

Efficient polyoxometalate (POM)-based Lewis acid-base catalysts of the rare-earth-metal-containing POMs (TBA(6)RE-POM, RE = Y(3+), Nd(3+), Eu(3+), Gd(3+), Tb(3+), or Dy(3+)) were designed and synthesized by reactions TBA(4)H(4)[γ-SiW(10)O(36)] (TBA tetra-n-butylammonium) with RE(acac)(3) (acac acetylacetonato). TBA(6)RE-POM consisted two silicotungstate units pillared rare-earth-metal cations. Nucleophilic oxygen-enriched surfaces negatively charged incorporated cations could work as bases...

The di- and tetranuclear metal sandwich-type silicotungstates of Cs10[(γ-SiW10O36)2{Zr(H2O)}2(μ-OH)2]·18H2O (Zr2, monoclinic, C2/c (No. 15), a = 25.3315(8) Å, b 22.6699(7) c 18.5533(6) β 123.9000(12)°, V 8843.3(5) Å3, Z 4), Cs10[(γ-SiW10O36)2{Hf(H2O)}2(μ-OH)2]·17H2O (Hf2, space group 25.3847(16) 22.6121(14) 18.8703(11) 124.046(3)°, 8974.9(9) Cs8[(γ-SiW10O36)2{Zr(H2O)}4(μ4-O)(μ-OH)6]·26H2O (Zr4, tetragonal, P41212 92), 12.67370(10) 61.6213(8) 9897.78(17)...

Zinc in: Polyoxometalate 1 reacts with Zn2+ ions in acetone to form a novel sandwich-type POM 2 almost quantitative yield. The H2O2-based oxidation of secondary alcohols efficiently proceeds, an activity and chemoselectivity that is very different from those tungsten-based catalysts including (see scheme; green Zn).

A novel dialuminum-substituted silicotungstate TBA3H[γ-SiW10O36{Al(OH2)}2(μ-OH)2]·4H2O (1, TBA = tetra-n-butylammonium) was synthesized by the reaction of potassium salt [γ-SiW10O36]8− (SiW10) with 2 equiv Al(NO3)3 in an acidic aqueous medium. It confirmed X-ray crystallographic analysis that compound 1 a monomer γ-Keggin {Al2(μ-OH)2} diamond core. The cluster framework maintained structure solution states. pyridine yielded TBA3[(C5H5N)H][γ-SiW10O36{Al(C5H5N)}2(μ-OH)2]·2H2O (2), and...

By the reaction of TBA(4)H(4)[γ-SiW(10)O(36)] (TBA = tetra-n-butylammonium) with AgOAc (OAc acetate) using dimethylphenylsilane as a reductant in acetone, unique polyoxometalate containing discrete octahedrally shaped [Ag(6)](4+) cluster, TBA(8)[Ag(6)(γ-H(2)SiW(10)O(36))(2)]·5H(2)O, could be synthesized, and molecular structure was determined.

A void in the issue: one-step self-assembly of γ-Keggin sandwich-type silicotungstates with M2Zn2 (M=Co, Ni, Zn) tetranuclear cores and tetrabutylammonium cations gave porous ionic crystals. These crystals are hollow frameworks containing large voids (ca. 38×38×38 Å3, see picture, yellow), between which guest molecules can be exchanged through connecting channels. Detailed facts importance to specialist readers published as "Supporting Information". Such documents peer-reviewed, but not...

The exploration of composition–structure–function relationship in proton-conducting solids remains a challenge materials chemistry. Polyoxometalate-based compounds have been long considered as candidates for proton conductors; however, their low structural stability and large decrease conductivity under reduced relative humidity (RH) limited applications. To overcome such limitations, the hybridization polyoxometalates with polymers has emerged promising method. Besides, 4f lanthanide ions...

Dicopper-substituted polyoxovanadate [Cu2V16O44(NO3)]5− (Cu2V16) was synthesized through the reaction of [Cu2V8O24]4− and [V4O12]4− in presence nitrate salt. From single crystal X-ray analysis, Cu2V16 exhibited same helical structure as that nitrate-incorporated polyoxovanadate, [V18O46(NO3)]5− (V18). Both complexes had framework with guest anion are considered to be substituted isomers for each other by replacing two Cu2+ ions [VO]2+ ions. The incorporated showed short long N–O bond lengths...

Polyoxometalates (POMs), anionic nanosized oxoclusters that can be considered as fragments of metal oxides, have been extensively studied for their diverse composition and structure, showing promise in various fields such catalysis electronics. Proton conduction, relevant to electronics, has attracted interest materials chemistry, POM anions are advantageous terms proton carrier density mobility. Recently, polar POMs attention unique ferroelectric behaviors, yet they little with regard...

Abstract The development of visible‐light‐induced photocatalysts for chemoselective functional group transformations has received considerable attention. Polyoxometalates (POMs) are potential materials efficient because their properties can be precisely tuned by changing constituent elements and structures the introduction additional metal cations. Furthermore, they thermally oxidatively more stable than frequently utilized organometallic complexes. visible‐light‐responsive tetranuclear...

Ein Yttrium-verbrücktes Silicowolframat-Dimer (siehe Bild) katalysiert die Cyanosilylierung von Ketonen und Aldehyden mit Trimethylsilylcyanid (TMSCN). Die Reaktionen verlaufen selektiv geben entsprechenden Cyanhydrintrimethylsilylether. katalytische Aktivität des Dimers ist vor allem für Aldehyde beeindruckend, einer Umsatzzahl 18 000 Umsatzfrequenz 540 h−1 n-Hexanal.

Polyoxometalates (POMs) are oxide cluster anions composed of high-valence early transition metals and widely used as catalysts. Yet base catalysis POMs remains an ongoing challenge; group V (V, Nb, Ta) elements form more negatively charged than VI (Mo W) elements, in particular, polyoxoniobates polyoxotantalates known to show strong basicity solution due the highly negative surface oxygen atoms. Herein, we report for first time porous ionic crystals (PICs) comprising Nb or Ta. The PICs...

A cobalt salt of a γ-Keggin dilacunary silicotungstate, {CoL5}2[γ-SiW10O34L2] [Co-SiW10; L = N,N-dimethylformamide (DMF) or H2O], could be synthesized by the cation-exchange reaction TBA4[γ-H4SiW10O36] (TBA tetra-n-butylammonium) with 2 equiv Co(NO3)2 respect to in mixed solvent DMF and acetone (97% yield). Each Co-SiW10 was linked water molecules via hydrogen-bonding network. Besides Co-SiW10, various kinds isostructural M-SiW10 same procedure as that for (M Mn2+, Fe2+, Ni2+, Cu2+, Zn2+,...

A Ti-substituted phosphotungstate (<bold>I</bold>) showed high catalytic performance for several oxidation reactions. The truly catalytically active species was successfully isolated, and its anion structure determined.

Abstract A tetranuclear cerium-containing polyoxometalate, TBA6[{Ce(H2O)}2{Ce(CH3CN)}2(µ4-O)(γ-SiW10O36)2] (I, TBA: tetra-n-butylammonium), showed a unique intramolecular multiple electron transfer (Ce3+-to-POM(W6+)) on irradiation of visible light (λ &amp;gt; 400 nm). This could induce hydrogen (H2) evolution using alcohols as the donors, and high turnover number (TON) 1960 was achieved. Moreover, I be reused without an appreciable loss in its catalytic performance.

Design of cavities for a target molecule and the elucidation corresponding host-guest interactions are important molecular manipulation. A discrete dodecavanadate bowl, [V12 O32 ]4- (V12), with an entrance diameter 4.4 Å electron-rich guest at center was stabilized by electrostatic interactions. characteristic V12 is solid-state polytopal rearrangement during elimination recapture. guest-free dodecavanadate, (V12-free), prepared removal from CH2 Cl2 -inserted under vacuum 50 °C....

Local structure change of the vanadium-oxygen cluster with nitrate at center controls catalytic performance in selective oxidation.

To construct an environmentally friendly crystalline proton conductor and establish a composition–structure–function relationship, polyoxometalate poly(vinyl alcohol), anionic metal-oxide cluster, polymer with hydroxyl groups, respectively, providing carriers conduction pathways, were combined lanthanide ion large coordination sphere to trap water effectively. The composite exhibited high conductivity of 8.3 × 10–3 S cm–1 at 368 K 75% relative humidity. We demonstrate the potential for...

A novel dinuclear zirconium sandwich-type silicotungstate cluster of [(gamma-SiW(10)O(36))(2)Zr(2)(mu-OH)(2)](10-) (1) was synthesized by the reaction a divacant lacunary gamma-Keggin [gamma-SiW(10)O(36)](8-) with ZrOCl(2).8H(2)O. The anion consisted two units sandwiching diamond Zr(2)(mu-OH)(2) core, and each atom in 1 six-coordinated to mu-OH ligands four oxygen atoms units. core reacted methanol give corresponding monomethoxo derivative [(gamma-SiW(10)O(36))(2)Zr(2)(mu-OH)(mu-OCH(3))](10-) (2).

Two novel sandwich-type silicotungstates, TBA8[{Zn2W(O)O3}2H4{α-SiW9O33}2]·5H2O (α-Zn4; TBA = tetra-n-butylammonium) and TBA8[{Zn2W(O)O3}2H4{β-SiW9O33}2]·7H2O (β-Zn4), were synthesized by the solid-state thermally induced isomerization of metastable TBA8[{Zn(OH2)(μ3-OH)}2{Zn(OH2)2}2{γ-HSiW10O36}2]·9H2O (γ-Zn4). Compounds α-Zn4 β-Zn4 consisted two [SiW9O33]8− subunits sandwiching unprecedented distorted hexaprismane core [{Zn2W(O)O3}2]4+.

The dodecavanadate framework, [V12O32]4-, exhibits a unique bowl-type structure with an open molecular oxide cage having cavity diameter of 4.4 Å, and different synthetic paths were required to construct the guest. A new dodecavanadate, {(n-C4H9)4N}4[V12O32(CH3NO2)] (1), is synthesized nitromethane guest, which stacked above entrance hemisphere rather than fully occupying cavity, it enables guest-capturing reaction, while retaining anionic structure. Compound 1 good precursor for...