(W6I8)Cl4 – A Basic Model Compound for Photophysically Active [(W6I8)L6]2– Clusters?

The heteroleptic cluster compound (W₆I₈)Cl₄ was prepared by thermal conversion of the homoleptic clusters W₆I₁₂ and W₆Cl₁₂ at 700 °C to yield a bright yellow powder. The presence of the smaller chlorido ligands in apical positions of [(W₆I₈)Cl₆]^2– creates nearly spherically clusters showing thermal and chemical inertness. Photoluminescence studies revealed a strong red phosphorescence from excited spin‐triplet states.     

Cubane Tellurido Clusters [Zn(NH3)4]3[Mo4Te4(CN)12] and [Cd(NH3)4]3[W4Te4(CN)12]: Syntheses and Crystal Structures

Single crystals of [Zn(NH₃)₄]₃[Mo₄Te₄(CN)₁₂] (I) and [Cd(NH₃)₄]₃[W₄Te₄(CN)₁₂] (II) were obtained by applying solutions of K₇[Mo₄Te₄(CN)₁₂] · 11H₂O and K₆[W₄Te₄(CN)₁₂] · 5H₂O in aqueous ammonia over solutions of ZnCl₂ and Cd(NO₃)₂ in glycerol and were characterized by X-ray diffraction analysis. The IR spectra and thermal properties of compounds I and II were examined.     

Polyoxometalate immobilization in Cu/Ag-pz porous coordination polymers: The influences of them on the structural properties of frameworks

Three new high dimensional Cu^I/Ag-pz porous coordination polymers (PCPs) with different Keggin polyoxometalate templates have been hydrothermally synthesized: [Cu^I₅(pz)₆Cl][HPMo^VI₁₀Mo^V₂O₄₀] (1) [Ag₅(pz)₇(BW₁₂O₄₀)] (2) and [Cu^I₅(pz)₆H(H₂W₁₂O₄₀)]·4H₂O (3) (pz=pyrazine). The choice of the particular Keggin POM templates is shown to influence the structural properties of the Cu/Ag PCPs. Compound 1 shows a Cl-bridged Cu-pz-Cl double layer, between which two kinds of [HPMo^VI₁₀Mo^V₂O₄₀]⁴⁻(PMo₁₂) polyanions are located. Compound 2 presents a 3D Ag-pz framework with parallelogram-like voids, into which BW₁₂O₄₀⁵⁻ (BW₁₂) Keggin ions are incorporated. Compound 3 contains a Cu-pz cationic layer framework, between which are located [H(H₂W₁₂O₄₀)]⁵⁻ (W₁₂) Keggin ions. Primary photocatalytic experiment indicates that compound 1 presents excellent photocatalytic activity. The photoluminescence properties and electrochemistry properties of the compounds are also discussed.     

Hydrothermal syntheses, crystal structures and properties of 0-D, 1-D and 2-D organic-inorganic hybrid borotungstates constructed from Keggin-type heteropolyanion [α-BW12O40] and transition-metal complexes

Three novel organic-inorganic hybrid borotungstates {[Ni(phen)₂(H₂O)]₂H(α-BW₁₂O₄₀)}·4H₂O (1), [Cu^I(2,2'-bipy)(4,4′-bipy)_0.5]₂{[Cu^I(2,2′-bipy)]₂Cu^I(4,4′-bipy)₂(α-BW₁₂O₄₀)} (2) and {[Cu^I(4,4′-bipy)]₃H₂(α-BW₁₂O₄₀)}·3.5H₂O (3) (phen=1,10-phenanthroline, 2,2′-bipy=2,2′-bipyridine, 4,4′-bipy=4,4′-bipyridine) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, UV spectra, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), single-crystal X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and photoluminescence. The structural analysis reveals that 1 consists of a 0-D bisupporting polyoxometalate cluster where two [Ni(phen)₂(H₂O)]²⁺ cations are grafted on the polyoxoanion [α-BW₁₂O₄₀]^5- through two terminal oxygen atoms, 2 shows a 1-D infinite chain constructed from [α-BW₁₂O₄₀]^5- polyoxoanions and {[Cu^I(2,2′-bipy)]₂Cu^I(4,4′-bipy)₂}³⁺ cations by means of alternating fashion, and 3 displays an unprecedented 2D extended structure built by [α-BW₁₂O₄₀]^5- polyoxoanions and -Cu^I-4,4′-bipy- linear chains, in which each [α-BW₁₂O₄₀]^5- polyoxoanion acts as a tetradentate inorganic ligand and provides three terminal oxygen atom and one two-bridging oxygen atom. The presence of Ni^II and W^VI in 1, Cu^I ions and W^VI in 2 and 3 are identified by XPS spectra. The photoluminescence of 2 and 3 are also investigated.     

A New 1D Chain-like Complex Built Up of Cu-containing Sandwich Tungstogermanate

Two new tungstogermanates K₂Na₁₀[Cu₄(GeW₉O₃₄)₂] · 15.5H₂O (1) and K₄Na₆[Cu_3.5W_0.5(H₂O)₂(GeW₉O₃₄)₂] · 17H₂O (2) have been obtained by the conventional aqueous solution methods and characterized by IR, element analysis, electrochemistry and single-crystal X-ray analysis. Compound 1 is composed of the [Cu₄(GeW₉O₃₄)₂]¹²⁻ anions linked by two equivalent bonds of Cu–O–W, representing the first one-dimensional chain-like structure based on sandwich-type polyoxometalates by direct condensation to form oxo-bridged arrays of clusters. Compound 2 is a sandwich structure, consisting of two trivacant [GeW₉O₃₄]¹⁰⁻ units linked by a [Cu_3.5W_0.5(H₂O)₂] cluster, and the anions are linked by the K⁺ and Na⁺ to form a three-dimensional structure. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A Facile Method for the Synthesis of Binary Tungsten Iodides

The preparation of tungsten iodides in large quantities is a challenge because these compounds are not accessible using an easy synthesis method. A new, remarkably efficient route is based on a halide exchange reaction between WCl₆ and SiI₄. The reaction proceeds at moderate temperatures in a closed glass vessel. The new compounds W₃I₁₂ (W₃I₈?2 I₂) and W₃I₉ (W₃I₈? I₂) containing the novel [W₃I₈] cluster are formed at 120 and 150 °C, and remain stable in air. W₃I₁₂ is an excellent starting material for the synthesis of other metal‐rich tungsten iodides. At increasing temperature these trinuclear clusters undergo self‐reduction until an octahedral tungsten cluster is formed in W₆I₁₂. The synthesis, structure, and an analysis of the bonding of compounds containing this new trinuclear tungsten cluster are presented.     

Cyanide Complexes Based on {Mo6I8}4+ and {W6I8}4+ Cluster Cores

Compounds based on new cyanide cluster anions [{Mo₆I₈}(CN)₆]^2–, trans-[{Mo₆I₈}(CN)₄(MeO)₂]^2– and trans-[{W₆I₈}(CN)₂(MeO)₄]²⁻ were synthesized using mechanochemical or solvothermal synthesis. The crystal and electronic structures as well as spectroscopic properties of the anions were investigated. It was found that the new compounds exhibit red luminescence upon excitation by UV light in the solid state and solutions, as other cluster complexes based on {Mo₆I₈}⁴⁺ and {W₆I₈}⁴⁺ cores do. The compounds can be recrystallized from aqueous methanol solutions; besides this, it was shown using NMR and UV-Vis spectroscopy that anions did not undergo hydrolysis in the solutions for a long time. These facts indicate that hydrolytic stabilization of {Mo₆I₈} and {W₆I₈} cluster cores can be achieved by coordination of cyanide ligands.     

New supramolecular adducts of chloroaquacomplexes [M3(μ3-S)S3?xSexCly(H2O)9?y](4?y)+ (M = Mo, W) with cucurbit[6]uril

New supramolecular adducts of cucurbit[6]uril with triangular cluster chloroaquacomplexes of Mo and W with mixed sulfido-selenido bridging ligands, {[W₃S₃Se(H₂O)₇Cl₂]₂(C₃₆H₃₆N₂₄O₁₂)}Cl₂·15H₂O (1), {[W₃S_1.5Se_2.5Cl_1.5(H₂O)_7.5]₂(C₃₆H₃₆N₂₄O₁₂)}Cl₅·18.5H₂O (2), and {[Mo₃SSe₃(H₂O)_7.5Cl_1.5]₂× (C₃₆H₃₆N₂₄O₁₂)}C_l5·11H₂O (3) are obtained treating the mixture of products in Mo-S-Se-Br and W-S-Se-Br systems, isolated, and structurally characterized. In all compounds, the supramolecular structure is based on hydrogen bonded associates of cucurbit[6]uril molecule with two cluster cations.     

[Ho5(H2O)16(OH)2As6W64O220]25−, ein großes neuartiges Polyoxoanion aus trivakanten Keggin‐Fragmenten

[Ho₅(H₂O)₁₆(OH)₂As₆W₆₄O₂₂₀]^25?, a Large Novel Polyoxoanion from Trivacant Keggin Fragments The novel polyoxotungstate Na₇K₁₈[Ho₅(H₂O)₁₆(OH)₂As₆W₆₄O₂₂₀] · 56 H₂O ( 1 ) was synthesized in aqueous solution and characterized by X‐ray structure analysis, elemental analysis and IR spectroscopy. The anion in 1 represents one of the largest polyoxoanions known yet and exhibits an unusual arrangement of six Keggin units. It consists of six trivacant lacunary α‐B‐(AsW₉O₃₃)^9? Keggin fragments which are connected by a bridging [Ho₅W₁₀(H₂O)₁₆(OH)₂O₂₂]²⁹⁺ unit. The five Ho^III atoms are coordinated by eight oxygen atoms, forming a square‐antiprism.     

Dodecanuclear rhenium cluster complexes with an interstitial carbon atom: Synthesis, structures and properties of two new compounds K6[Re12CS17(OH)6]·4H2O and Na12Re12CS17(SO3)6·48.5H2O

The dodecanuclear rhenium anionic complex with terminal hydroxo ligands [Re₁₂CS₁₇(OH)₆]⁶⁻ was obtained by the reaction of K₆[Re₁₂CS₁₇(CN)₆]·20H₂O with molten KOH at 300 °C. The cluster complex was crystallized as a potassium salt from aqueous solution. The reaction between K₆[Re₁₂CS₁₇(OH)₆]·4H₂O and Na₂S₂O₄ in water under reflux results in the formation of the complex Na₁₂[Re₁₂CS₁₇(SO₃)₆]·48.5H₂O. Both new compounds were characterized by single-crystal X-ray diffraction, elemental analyses and IR spectroscopy. The electronic structure of [Re₁₂CS₁₇(OH)₆]⁶⁻ was also elucidated by DFT calculations.     

Triangular telluride complexes containing a cluster fragment [M3(µ3-Te)(µ2-Te2)3]4+ (M = Mo, W): Study of specific non-valence interactions

Various synthetic approaches are used to obtain new triangular complexes with rare cluster nuclei M₃Te₇ ⁴⁺ (M = Mo, W), as well as with partial substitution for chalcogen W₃Te_3.8Se _3.2 ⁴⁺ . The crystalline structure has been identified for K₅{[Mo₃Te₇(CN)₆]₂I}·2.5H₂O (I), K₃{[Mo₃Te₇(CN)₆]SeCN}·3.25H₂O (II), Cs₂K{ [W₃Te₇(CN)₆]Br_0.8Cl_0.2}·2.5H₂O (III), Cs₃{ [W₃Te₇(CN)₆]Br}·2H₂O (IV), Cs_1.59K_1.41{[W₃Te_3.8Se_3.2× ×(CN)₆]Br}·1,5H₂O (V), [W₃Te₇((EtO)₂PS₂)₃]Br (VI). The compounds are characterized by IR methods and electronic spectroscopy, electrospray-mass-spectrometry. The crystalline structure of this class of compounds is analyzed. Specific non-valence interactions in these systems are considered in detail.     

Synthesis and crystal structure of KNa3[Fe3O(CH3COO)6(H2O)2]3 [α-P2W17Fe(H2O)O61]·32.5H2O

A complex of the composition KNa₃[Fe₃O(CH₃COO)₆(H₂O)₃]₃ [α-P₂W₁₇Fe(H₂O)O₆₁]·32.5H₂O (I) was obtained by interaction of FeCl₃·6H₂O and phosphotungstate K₁₀[α₂-P₂W₁₇O₆₁]·20H₂O in an acetate buffer with a yield of 52%. Compound I was characterized by single crystal X-ray phase analysis and IR spectroscopy. In the crystal structure, the Na and K cations bind [Fe₃O(CH₃COO)₆(H₂O)₃]⁺ trinuclear cations and [α-P₂W₁₇Fe(H₂O)O₆₁]⁷⁻ heteropolytungstate anions into infinite zigzag chains. Original Russian Text Copyright ? 2005 by N. V. Izarova, M. N. Sokolov, A. V. Virovets, H. G. Platas, and V. P. Fedin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 1, pp. 149–155, January–February, 2005.     

Ein oktaedrischer Niobcluster mit sechs terminalen Azidgruppen: Die Struktur von Rb4[Nb6Br12(N3)6](H2O)2

An Octahedral Niobium Cluster containing Six Terminal Azide Groups: The Structure of Rb₄[Nb₆Br₁₂(N₃)₆](H₂O)₂ Six terminal halide ligands of [Nb₆Br₁₂Br₆]^4? can be substituted in solution by azide ions. Single-crystals of Rb₄[Nb₆Br₁₂(N₃)₆](H₂O)₂ were obtained during the evaporation of the water/methanol solvent, and structurally characterized by X-ray methods: Space group P2₁/c, Z = 2, a = 970.8(5) pm, b = 1525.4(7) pm, c = 1280.0(7) pm, β = 97.15(6)°. The [Nb₆Br₁₂(N₃)₆]^4? ions contain six terminal azide groups at the corners of the octahedral niobium cluster (d _Nb–N = 227 pm). The [Nb₆Br₁₂(N₃)₆]^4? ions are interconnected by Rb⁺ and H₂O. Crystals of Rb₄[Nb₆Br₁₂(N₃)₆](H₂O)₂ are explosive towards heat or mechanic pressure.     

Synthesis, crystal structure, spectroscopic and thermal properties of [Et4N][Ta6Br12(H2O)6]Br4·4H2O (Et=ethyl)—A new compound with the paramagnetic [Ta6Br12] cluster core

A new hexanuclear cluster compound, [Et₄N][Ta₆Br₁₂(H₂O)₆]Br₄·4H₂O (Et=ethyl) (1), with the paramagnetic [Ta₆Br₁₂]³⁺ cluster entity, was synthesized and characterized by elemental and TG/DTA analyses, IR and UV/Vis spectroscopy and by a single-crystal X-ray diffraction study. The presence of the paramagnetic [Ta₆Br₁₂]³⁺ unit was confirmed also by the room-temperature magnetic and EPR measurements. The compound crystallizes in the tetragonal I4₁/a space group, with a=14.299(5), c=21.241(5) Å, Z=4, R₁(F)/wR₂(F²)=0.0296/0.0811. The structure contains discrete [Ta₆Br₁₂(H₂O)₆]³⁺ cations with an octahedron of metal atoms edge-bridged by bromine atoms and with water molecules occupying all six terminal positions. The cluster units are positioned in the vertices of the three-dimensional (pseudo)diamond lattice. The structure shows similarities with literature reported structures of cluster compounds crystallizing in the diamond space group.     

The Structure and Optical Properties of the [Au18(SR)14] Nanocluster

Decreasing the core size is one of the best ways to study the evolution from Au^I complexes into Au nanoclusters. Toward this goal, we successfully synthesized the [Au₁₈(SC₆H₁₁)₁₄] nanocluster using the [Au₁₈(SG)₁₄] (SG=L ‐glutathione) nanocluster as the starting material to react with cyclohexylthiol, and determined the X‐ray structure of the cyclohexylthiol‐protected [Au₁₈(C₆H₁₁S)₁₄] nanocluster. The [Au₁₈(SR)₁₄] cluster has a Au₉ bi‐octahedral kernel (or inner core). This Au₉ inner core is built by two octahedral Au₆ cores sharing one triangular face. One transitional gold atom is found in the Au₉ core, which can also be considered as part of the Au₄(SR)₅ staple motif. These findings offer new insight in terms of understanding the evolution from [Au^I(SR)] complexes into Au nanoclusters.     

Alkaline Earth Cluster Compounds AE[W6I14] and the Solvate [Ca(C2H6SO)6][W6I14]

Alkaline earth tungsten iodide clusters AE[W₆I₁₄] with AE = Mg, Ca, Sr, Ba and the solvated compound [Ca(C₂H₆SO)₆][W₆I₁₄] were prepared and structurally characterized. A new synthesis was employed, starting from W₆I₂₂, which is an exceptional compound among binary tungsten iodides because it is soluble in common polar organic solvents. As evidence for the wide range of the applicability of W₆I₂₂, we report the synthesis of the new AE[W₆I₁₄] compounds in comparison to a solid‐state reaction departing from W₃I₁₂.     

Bulky Cations and Four different Polyiodide Anions in [Lu(Db18c6)(H2O)3(thf)6]4(I3)2(I5)6(I8)(I12)

Black single crystals of [Lu(Db18c6)(H₂O)₃(thf)₆]₄(I₃)₂(I₅)₆(I₈)(I₁₂) were obtained from lutetium, I₂ and Db18c6 (dibenzo‐18‐crown‐6) in THF solution. In the bulky cation, Lu³⁺ is surrounded by nine oxygen atoms, six of Db18c6 and three of water molecules to which two THF molecules are attached each. Meanwhile, four polyiodide anions, (I₃)^–, (I₅)^–, (I₈)^2– and (I₁₂)^2–, in a 2:6:1:1 ratio form a three‐dimensional network and leave space for the bulky cations.     

One-dimensional inorganic-organic hybrid material [Cu(En)2]2H2[{Cu(En)2}2(H2W12O42)] · 6.5H2O: Hydrothermal syntheses and crystal structure

A novel inorganic-organic hybrid material, [Cu(En)₂]₂H₂[{Cu(En)₂}₂(H₂W₁₂O₄₂)] · 6.5H₂O (I) based on polyoxotungstates and Cu²⁺ ions, has been successfully synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction, IR spectra, and TG analysis. Structural analysis indicates that the structure consists of a one-dimensional structure constructed from the polyoxoanion [H₂W₁₂O₄₂]¹⁰⁻ bridged by {Cu(En)₂}²⁺ groups. Each [H₂W₁₂O₄₂]¹⁰⁻ cluster in the polymeric chain is linked to two neighbors through four coordination groups of μ₂-[Cu(En)₂]²⁺. Furthermore, it extends into a three-dimensional supramolecular network by hydrogen bonding interactions.     

[La2I2(OH)2(Dibenzo-18-Krone-6)2]I(I3), ein kationischer,dimerer in-cavity-Komplex mit Iodid und Triiodid als Anionen

[La₂I₂(OH)₂(dibenzo-18-crown-6)₂]I(I₃), a Cationic Dimeric in-cavity Complex with Iodide and Triiodide as Anions Single crystals of [La₂I₂(OH)₂(dibenzo-18-crown-6)₂]I(I₃) are obtained from the reaction of LaI₃ and dibenzo-18-crown-6 in acetonitrile. The crystal structure monoclinic, C2/m, Z = 4, T = 293 [100] K, a = 2179(3) [2162.3(3)], b = 1070.3(3) [1069.6(1)], c = 1118.2(3) [1110.6(1)] pm, β = 93.1(1) [92.83(1)]°, R1 = 0.0601 [0.0411], wR2 = 0.1449 [0.1014] contains hydroxide-bridged cationic dimers and iodide as well as triiodide as anions.     

Facile preparation of an α-Keggin-type [H3W12O40] complex: Does it exist in aqueous solution?

The formation processes of α-Keggin-type [H₂W₁₂O₄₀]⁶⁻ and [H₃W₁₂O₄₀]⁵⁻ complexes were investigated in aqueous W^VI (0.05–0.50 M) solutions. The formation of [H₂W₁₂O₄₀]⁶⁻ was ascertained by the appearance of a ¹⁸³W NMR line at −117 ppm, but no evidence was found for the existence of [H₃W₁₂O₄₀]⁵⁻ in the solution at the accessible pH range. The addition of (CH₃)₄N⁺ (Me₄N⁺) to the W^VI solution directly precipitated the (Me₄N)₆[H₂W₁₂O₄₀] salt. On the other hand, the addition of the larger Bu₄N⁺ cation precipitates the (Bu₄N)_4.5H_0.5[H₃W₁₂O₄₀] salt, because a naked proton formed during the crystallization process or in the solid state may enter into the Keggin shell to produce [H₃W₁₂O₄₀]⁵⁻. This explanation is based on the fact that [H₂W₁₂O₄₀]⁶⁻ is not spontaneously converted into [H₃W₁₂O₄₀]⁵⁻ in acidified aqueous solution. On the basis of their voltammetric properties, a simple diagnostic criterion was developed to distinguish between [H₂W₁₂O₄₀]⁶⁻ and [H₃W₁₂O₄₀]⁵⁻.