Low-temperature preparation of tungsten halide clusters: Crystal structure of the adduct W<Subscript>5</Subscript>Br<Subscript>12</Subscript> · SbBr<Subscript>3</Subscript>

Single-crystals of a new compound W₅Br₁₂ · SbBr₃ (I) were isolated as a reaction product from the reduction of WBr₆ with elemental antimony at 250°C. The crystal structure was determined by single-crystal X-ray diffraction analysis. The structure contains square-pyramidal tungsten clusters being linked into infinite [(W₅Br₈ⁱ)Br₃^aBr₂^2/a-a] chains through shared W-Br^a-a-W contacts of adjacent clusters. The structure of the adduct I can be viewed as an intercalation compound composed of double-layers of cluster chains alternating with mono-layers of SbBr₃ molecules.     

The Cluster Compounds Ag[W6Br14] and Ag2[W6Br14]

The reaction of W₆Br₁₂ with AgBr in evacuated silica tubes (temperature gradient 925 K/915 K) yielded brownish black octahedra of Ag[W₆Br₁₄] ( I ) and yellowish green platelets of Ag₂[W₆Br₁₄] ( II ) both in the low temperature zone. ( I ) crystallizes cubically (Pn3 (no. 201); a = 13.355 Å, Z = 4) and ( II ) monoclinically (P2₁/c (no. 14); a = 9.384 Å, b = 15.383 Å, c = 9.522 Å, β = 117.34°, Z = 2). Both crystal structures contain isolated cluster anions, namely [(W₆Brⁱ₈)Br^a₆]^1– and [(W₆Brⁱ₈)Br^a₆])]^2–, respectively, with the mean distances and angles: ( I ) d(W–W) = 2.648 Å, d(W–Brⁱ) = 2.617 Å, d(W–Br^a) = 2.575 Å, d(Brⁱ…Brⁱ) = 3.700 Å, d(Brⁱ…Br^a) = 3.692 Å, ∠W–Brⁱ–W = 60.78°. ( II ) d(W–W) = 2.633 Å, d(W–Brⁱ) = 2.624 Å, d(W–Br^a) = 2.613 Å, d(Brⁱ…Brⁱ) = 3.710 Å, d(Brⁱ…Br^a) = 3.707 Å, ∠W–Brⁱ–W = 60.23°. The Ag⁺ cations are trigonal antiprismatically coordinated in ( I ) with d(Ag–Br) = 2.855 Å, but distorted trigonally planar in ( II ) with d(Ag–Br) = 2.588–2.672 Å. The structural details of hitherto known compounds with [W₆Br₁₄] anions will be discussed.     

Synthese und Kristallstruktur der molekularen Clusterverbindung W6Br14

Synthesis and Crystal Structure of the Molecular Cluster Compound W₆Br₁₄ Brownish-black crystals of W₆Br₁₄ are formed in the direct synthesis from W₆Br₁₂ and Br₂ (400 K). The compound crystallizes cubically with neutral cluster molecules ([W₆Br]Br): a = 13.458 Å; Pn3 (Nr. 201); d?(W? W) = 2.653 Å; d?(W? Brⁱ) = 2.616 Å; d?(W? Br^a) = 2.569 Å. The W atoms are 0.03 Å outside of the Br cube faces. The molecules are arranged according to a cF point configuration, but each is rotated ?23° about a threefold axis in order to avoid short inter cluster distances Br^a? Br^a. Nevertheless, via 12 short intermolecular distances per cluster of about d(Brⁱ …? Br^a) = 3.487 Å the clusters are interconnected by forming two independent and interpenetrating 3D nets (Cu₂O type). Although local distortion of the M₆X cluster does not occur, as is expected for this system with 22 electrons per M₆ octahedron, it is assumed that the Jahn-Teller theorem is fulfilled collectively via the low-symmetry nets of intermolecular interactions.     

Two Modifications of Copper(I) Octahedro-Hexatungsten(II) Tetradecabromide,Cu2[W6Br14]

The reaction of W₆Br₁₂ with CuBr sealed in an evacuated silica tube at the temperature gradient 925/915 K and annealing at 625/300 K yields a mixture of orthorhombic α-Cu₂[W₆Br₁₄] and cubic β-Cu₂[W₆Br₁₄] in the low temperature zone. α-Cu₂[W₆Br₁₄] crystallizes in the space group Pbca (no. 61), a = 15.126 Å, b = 9.887 Å, c = 15.954 Å, Z = 4, oP88, and β-Cu₂[W₆Br₁₄] crystallizes in the space group Pn3 (no. 201), a = 13.391 Å, Z = 4, cP88. The crystal structures are built up by [(W₆Br)Br]^2– cluster anions and Cu⁺ cations. The cluster anions show only in the peripheral shells small deviation from m3m symmetry (d(W–W) = 2.630 Å; d(W–Brⁱ) = 2.618 Å; d(W–Br^a) = 2.614 Å). The anions are arranged in a slightly compressed bcc pattern (α) and ccp (β) pattern, respectively. The Cu⁺ cations are trigonal-planar coordinated by Br^a ligands with d(Cu–Br) = 2.377 Å (α) and 2.378 Å (β). The cubic β-modification is diamagnetic with an unexpected large susceptibility (χ_mol = –884 × 10^–6 cm³ mol^–1) and have a band gap of 2.8 eV. It decomposes under dynamic vacuum in two steps at 795 K und 1040 K.     

Die Umwandlung [W6X8]X4 [W6X12]X6 (X = Cl,Br)

Transformation of [W₆X₈]X₄ + 3 X₂ = [W₆X₁₂]X₆ (X = Cl, Br) The transformation of [W₆X₈]X₄ + 3 X₂ = [W₆X₁₂]X₆ (X = Cl, Br) has been investigated by changing the relation Cl₂/Br₂ and the temperature. In this way the compounds [W₆Br_12?nCl_n]Cl_6?mBr_m are isolated. All of the products are isotypic with W₆Cl₁₈ and W₆Br₁₈. Most often n equals 6, however compounds with other relations of Cl/Br are also observed (e. g. n = 4.8) The 6 ligands standing outside of the brackets are replaced by Cl or Br. The substitution of [W₆Br₆Cl₆]Cl₆ by means of bromine leads to the cluster [W₆Br₁₂]X₆. The backward transformation of the cluster compound [W₆Br₁₂]Br₆ happens by decomposition on the thermobalance, e. g. according to Gl. (1) (See Inhaltsübersicht). By analogy [W₆Br₁₂]Cl₆ is decomposed to [W₆Br₈]Cl₂Br₂, which by treatment with conc. HCl is transformed into [W₆Br₈]Cl₄ · 2 H₂O.     

Syntheses and Crystal Structures of the Cluster Compounds A2[(W6Br)Br] with A = K,Rb, Cs

K₂W₆Br₁₄ ( I ), Rb₂W₆Br₁₄ ( II ), and Cs₂W₆Br₁₄ ( III ) were formed by reactions of W₆Br₁₂ with the corresponding alkali metal bromides in evacuated silica tubes with a temperature gradient of 925 K/915 K. ( I ) crystallizes in the cubic space group Pn3 (no. 201), a = 13.808 Å, Z = 4, cP88. ( II ) crystallizes in the monoclinic space group C2/c (no. 15), a = 20.301 Å, b = 15.396 Å, c = 9.720 Å, β = 115.69°, Z = 4, mC88. ( III ) crystallizes in the trigonal space group P31c (no. 163), a = 10.180 Å, c = 15.125 Å, Z = 2, hP44. The crystal structures are composed of the isolated [(W₆Br)Br]^2– cluster anions and the alkali metal cations (d(W–W) = 2.635(2) Å, d(W–Brⁱ) = 2.624(4) Å, d(W–Br^a) = 2.595(4) Å). The shape of the anions is influenced by the crystal field symmetry, but the mean bond lengths are not changed by the cation size. The packing of the cluster anions corresponds to ccp pattern in ( I ) and hcp pattern in ( II ) and ( III ), respectively. The alkali metal cations in the octahedral holes are coordinated only by the Br^a ligands while those in the tetrahedral and trigonal-bipyramidal cavities are surrounded by Br^a and Brⁱ ligands. The details will be discussed and compared with other structures.     

Antimony(V) Bromide and Polybromide Complexes with N‐alkylated Quinolinium or Isoquinolinium Cations: Substituent‐dependent Assembly of Polymeric Frameworks

Reactions of [Sb^IIIBr₆]^3– with Br₂ in HBr in the presence of N‐substituted quinolinium or isoquinolinium cations result in new complexes of hexabromidoantimonates of Sb^V and their polybromide adducts: (N‐MeQuin)₂{[SbBr₆](Br₃)} ( 1 ), (N‐MeIsoquin)₂{[SbBr₆](Br₃)} ( 2 ), and (N‐EtQuin)[SbBr₆] ( 3 ). Thermal stability was studied; estimated energies of supramolecular Br ··· Br interactions were calculated.     

The Mixed Valence Tungsten(IV,V) Compound Na[W2O2Br6]

The reaction of W₆Br₁₂, NaBr, and WO₂Br₂ in the presence of Br₂ in a sealed silica tube yields Na[W₂O₂Br₆] together with WOBr₄ and WO₂Br₂ in the low temperature zone (temperature gradient 1030/870 K). Na[W₂O₂Br₆] crystallizes orthorhombically in the space group Immm (no. 71) with a = 3.775 Å, b = 10.400 Å, c = 13.005 Å and Z = 2. Pairs of condensed trans-[WO₂Br₄] octahedra with a common Br₂ edge form along [100] double chains [W₂O_4/2Br₆]^1– via the oxygen atoms. The mixed valent tungsten atoms are bonded to W₂ pairs with a 2 c–3 e bond (d(W–W) = 2.946 Å, d(W–O) = 1.888 Å, d(W–Br^b) = 2.537 Å, d(W–Br^t) = 2.535 Å, ∢O–W–O = 177.4°, ∢Br^b–W–Br^b (endocyclic) = 109.0°). The Na⁺ cations connect the anionic double chains to form two-dimensional layers parallel (001), which interact by van der Waals forces. The cations are eightfold coordinated by a cube of the terminal Br^t ligands of the polymeric anions (d(Na–Br) = 3.138 Å). Na[W₂O₂Br₆] may be discussed as an intercalation compound of the oxide bromide WOBr₃.     

Synthese,Kristallstrukturen und 121Sb-Mößbauer-Spektren von [SbBr3(15-Krone-5)], [SbBr2Me(15-Krone-5)] und [SbBr2Ph(15-Krone-5)]

Synthesis, Crystal Structure, and ¹²¹Sb-Mössbauer Spectra of [SbBr₃(15-Crown-5)], [SbBr₂Me(15-Crown-5)], and [SbBr₂Ph(15-Crown-5)] The compounds [SbBr₃(15-crown-5)] ( 1 ), [SbBr₂Me(15-crown-5)] ( 2 ), [SbBr₂Ph(15-crown-5)] ( 3 ), and [SbCl₂Me(15-crown-5)] ( 4 ) are formed by the reaction of 15-crown-5 with SbBr₃, SbBr₂Me, SbBr₂Ph, and SbCl₂Me, respectively, in toluene solution at ?40°C. The complexes were characterized by IR spectroscopy, ¹²¹Sb-Mössbauer spectroscopy, 1–3 as well as by X-ray structure determinations.

• 1 : Space group P2₁2₁2₁, Z = 4, 1735 observed, independent reflections, R = 0.050, Lattice dimensions at ?65°C: a = 787.03(7); b = 1313.0(2); c = 1619.3(2) pm.
• 2 : Space group Pca2₁, Z = 8, 2730 observed, independent reflections, R = 0.050, Lattice dimensions at ?65°C: a = 1308.2(2); b = 1611.8(2); c = 1640.5(3) pm.
• 3 : Space group P2₁/n, Z = 4,2458 observed, independent reflections, R = 0.040, Lattice dimensions at ?60°C: a = 900.3(3); b = 1390.6(6); c = 1618.5(7) pm, β = 96.32(3)°.

The complexes 1–3 have molecular structures, in which the antimony atoms are surrounded by the five oxygen atoms of the crown ether molecule and by three ligands Br₃, Br₂CH₃, Br₂Ph, respectively.     

The Cocrystallization of the Cubic [Ta6Br12(H2O)6][CuBr2X2]·10H2O and Triclinic [Ta6Br12(H2O)6]X2·trans‐[Ta6Br12(OH)4(H2O)2]·18H2O (X = Cl,Br, NO3) Phases with the Coexistence of [Ta6Br12]2+ and [Ta6Br12]4+ in the Latter

Cubic [Ta₆Br₁₂(H₂O)₆][CuBr₂X₂]·10H₂O and triclinic [Ta₆Br₁₂(H₂O)₆]X₂·trans‐[Ta₆Br₁₂(OH)₄(H₂O)₂]·18H₂O (X = Cl, Br, NO₃) cocrystallize in aqueous solutions of [Ta₆Br₁₂]²⁺ in the presence of Cu²⁺ ions. The crystal structures of [Ta₆Br₁₂(H₂O)₆]Cl₂·trans‐[Ta₆Br₁₂(OH)₄(H₂O)₂]·18H₂O ( 1 ) and [Ta₆Br₁₂(H₂O)₆]Br₂·trans‐[Ta₆Br₁₂(OH)₄(H₂O)₂]·18H₂O ( 3 )have been solved in the triclinic space group P&1macr; (No. 2). Crystal data: 1 , a = 9.3264(2) Å, b = 9.8272(2) Å, c = 19.0158(4) Å, α = 80.931(1)?, β = 81.772(2)?, γ = 80.691(1)?; 3 , a = 9.3399(2) Å, b = 9.8796(2) Å, c = 19.0494(4) Å; α = 81.037(1)?, β = 81.808(1)?, γ = 80.736(1)?. 1 and 3 consist of two octahedral differently charged cluster entities, [Ta₆Br₁₂]²⁺ in the [Ta₆Br₁₂(H₂O)₆]²⁺ cation and [Ta₆Br₁₂]⁴⁺ in trans‐[Ta₆Br₁₂(OH)₄(H₂O)₂]. Average bond distances in the [Ta₆Br₁₂(H₂O)₆]²⁺ cations: 1 , Ta‐Ta, 2.9243 Å; Ta‐Brⁱ , 2.607 Å; Ta‐O, 2.23 Å; 3 , Ta‐Ta, 2.9162 Å; Ta‐Brⁱ , 2.603 Å; Ta‐O, 2.24 Å. Average bond distances in trans‐[Ta₆‐Br₁₂(OH)₄(H₂O)₂]: 1 , Ta‐Ta, 3.0133 Å; Ta‐Brⁱ, 2.586 Å; Ta‐O(OH), 2.14 Å; Ta‐O(H₂O), 2.258(9) Å; 3 , Ta‐Ta, 3.0113 Å; Ta‐Brⁱ, 2.580 Å; Ta‐O(OH), 2.11 Å; Ta‐O(H₂O), 2.23(1) Å. The crystal packing results in short O···O contacts along the c axes. Under the same experimental conditions, [Ta₆Cl₁₂]²⁺ oxidized to [Ta₆Cl₁₂]⁴⁺ , whereas [Nb₆X₁₂]²⁺ clusters were not affected by the Cu²⁺ ion.     

New Ternary Hafniumhalides: Cs[Hf2Br9] and Rb[Hf2Br9]

The syntheses and crystal structures of two new ternary hafnium compounds, Cs[Hf₂Br₉] ( 1 ) and Rb[Hf₂Br₉] ( 2 ), are described. Both compounds are obtained in high yield from the chemical reaction of HfBr₄ and CsBr or RbBr, respectively, in the presence of a small amount of elemental Al at 450 °C in sealed silica tubes. They crystallize isostructurally in the monoclinic space group P2/n. The lattice parameters are a = 9.946(1) ( 1 ) and 9.9388(4) Å ( 2 ), b = 6.6580(9) ( 1 ) and 6.6695(3) Å ( 2 ), c = 12.930(2) ( 1 ) and 12.8435(6) Å ( 2 ), and β = 112.479(6)° ( 1 ) and 112.726(2)° ( 2 ). The crystals of the two compounds contain dinuclear tri‐μ‐bromido‐hexabromido‐dihafnate(–) complex anions, [Hf₂Br₉]^–, besides the alkali metal cations. The complex anions can be described as face‐sharing bioctahedral units.     

New synthetic routes for the preparation of the triangular trinuclear clusters of tungsten-containing bromine atoms as terminal ligands: Structural characterization of [W3S4Br3(depe)3]PF6·0.5C7 H8 and [W3S4Br3(depe)3]Br·2CH3OH

Synthetic methods are reported for the preparation of compounds containing the trinuclear triangular cluster [W₃S₄Br₃(depe)₃[⁺. These involve reactions between WBr₅ and NaB(C₂ H₅)₃H or NaBH₄ as reducing agent in THF, and subsequent addition of methanolic solutions of NaHS and depe ligand. Both compounds, [W₃S₃Br₃(depe)₃]PF₆·0.5C₇H₈,1, and [W₃S₄Br₃(depe)₃]Br·2CH₃OH,2, are characterized by x-ray single crystal studies. Compounds1 and2 crystallize in space group \(P\bar 1\) . For1,a=10.427 (3) Å,b=15.415(4) Å,c=18.140(5) Å, α=79.36(2)°, β=73.59(2)°, γ=81.54(2)°, andV=2734.8(2) ų;R=0.050 and for 2a=10.491(3) Å,b=15.074(3) Å,c=18.246 Å, α=95.76(2)°, β=105.82(2)°, γ=98.18(2)°, andV=2718.4(3) ų;R=0.081. The two cations in1 and2 possess C₃ symmetry. The W-W distances are in the range 2.783?2.891 Å (for1) and 2.778?2.785 Å (for2) and the average W-Br distances in1 and2 are 2.616[2] Å and 2.594[4] Å, respectively. Each metal atom in the [W₃S₄Br₃(depe)₃]⁺ ions is attached to one capping sulfur atom, two bridging sulfur atoms, one bromine atom, and one chelating depe ligand. One P atom in depe ligand istrans to μ₃-S and the otherP atom istrans to a μ₂-S atom. UV-Vis and NMR spectra for these compounds are also reported.     

The first seven-electron triangular tungsten sulfide cluster

A new cluster complex [W₃S₄(Dppe)₃Br₃] · 3THF (Dppe = Ph₂PCH₂CH₂PPh₂), the first example of a triangular tungsten cluster with a seven-electron core, was synthesized. The molecular and crystal structures of the compound were determined by X-ray diffraction.     

Simplified Synthesis and Structural Study of { Ta6Br12} Clusters

Direct reaction of stoichiometric amounts of KBr, tantalum and bromine at 720 °C, followed by extraction and crystallization gives Ta₆Br₁₄ · 7H₂O (1) . This compound slowly aquates into [(Ta₆Br₁₂)(H₂O)₆]²⁺, which crystallized as mixed Cs⁺/Br^– ( 2 ), Cl^– ( 3 ) and SO₄^2– ( 4 ) salts. In Bu₄NBr melt, 1 undergoes oxidation into (Bu₄N)₂[(Ta₆Br₁₂)Br₆] ( 5 ). Reaction of 1 with dimethylsulfoxide also induces oxidation of the { Ta₆Br₁₂} ²⁺ core into { Ta₆Br₁₂} ⁴⁺, and the corresponding complex [(Ta₆Br₁₂)(dmso)₂Cl₄] · iPrOH · 4.8H₂O ( 6 ) was isolated and structurally characterized. Molecular and crystal structures for 2 – 6 were determined.     

Bi24Ru3Br20: Ein pseudo-tetragonales Subbromid mit [RuBi6Br12]-Clustern und [Ru2Bi17Br4]-Gruppen

Bi₂₄Ru₃Br₂₀: A Pseudo-Tetragonal Structure with [RuBi₆Br₁₂] Clusters and [Ru₂Bi₁₇Br₄] Groups The melting reaction of Ru with Bi and BiBr yields black, lustrous, air insensitive crystals of the subbromide Bi₂₄Ru₃Br₂₀. The orthorhombic crystal structure (space group Pc2₁n, a = b = 1377.8(1) pm, c = 3222.3(4) pm, V = 6117.0 · 10⁶ pm³) deceives pseudo-symmetry with respect to the tetragonal space group P4/ncc leading to multiply twinned crystals. The structure can formally be subdivided in [RuBi₆Br₁₂] clusters, [Ru₂Bi₁₇Br₄] stacks, and [BiBr₄] groups.     

A convenient solution method for conversion of a W(II) octahedral cluster to W(IV) triangular cluster: synthesis and characterization of Cs3Na2[W3Se4(CN)9] · 0.5Et4NBr · 5H2O

A new solution method for the preparation of a triangular W(IV) cluster starting from an octahedral W(II) cluster is reported. The product Cs₃Na₂[W₃Se₄(CN)₉]?·?0.5Et₄NBr?·?5H₂O (1) has been synthesized by boiling W₆Br₁₂ in an aqueous solution of Na₂Se _x , followed by filtering off the dark solid which was then heated with an aqueous solution of NaCN and crystallized by the addition of CsBr and Et₄NBr. The compound was characterized by IR, UV-Vis, elemental analysis, and single crystal X-ray diffraction. The described W(II)-to-W(IV) conversion in solution is reported for the first time.     

Synthesis,structure and luminescence properties of new chalcogenide octahedral rhenium cluster complexes with 4-aminopyridine [{Re6Q8}(4-NH2-py)6]2+

Two new cationic octahedral rhenium cluster complexes [{Re₆Q₈}(4-NH₂-py)₆]²⁺ (Q=S, Se; 4-NH₂-py = 4-aminopyridine) were synthesized by reactions of cesium salts of cluster anions [{Re₆Q₈}Br₆]^4?/3? with molten 4-aminopyridine. Both complexes were separated as salts with Br^? as counterions and the structure of [{Re₆S₈}(4-NH₂-py)₆]Br₂·6DMF was revealed by X-ray single-crystal diffraction analysis. The compounds were characterized by elemental analysis, energy dispersive X-ray, IR, NMR, and luminescence spectroscopies.     

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.     

Die Kristallstruktur von Ph3PNBr · Br2

Crystal Structure of Ph₃PNBr · Br₂ Ph₃PNBr · Br₂ ( 1 ) has been prepared besides of other products from the reaction of Ph₃PNH with bromine, forming orange‐yellow single crystals which are characterized by IR‐spectroscopy and by a crystal structure determination. Space group P2₁/n, Z = 4, lattice dimensions at 20 °C: a = 916.76(10), b = 1351.42(8), c = 1494.9(2) pm, β = 96.191(5)°, R₁ = 0.0538. 1 has a molecular structure in which the Br₂ molecule is coordinated at the nitrogen atom of the N‐bromine‐phosphoraneimine Ph₃PNBr in a linear arrangement N–Br–Br with bond lengths N–Br of 224.5(6) pm and Br–Br of 248.4(1) pm. The nitrogen atom of 1 is ψ‐tetrahedrally coordinated in addition by the phosphorus atom with a P–N distance of 165.3(6) pm and by the covalently bonded bromine atom with a bond length of 188.9(6) pm.     

Synthese und Struktur des μ-Sulfido-μ-disulfido-octabromodiwolframat(V)-Ions [W2S3Br8]2−

Synthesis and Structure of μ-Sulfido-μ-disulfido-octabromoditungstate(V), [W₂S₃Br₈]^?2 Tungsten hexabromide reacts with H₂S in dichloromethane yielding a brown product which, by addition of tetraphenylphosphonium bromide in CH₂Cl₂, is converted to brown, crystalline (PPh₄)₂[Br₄W(μ-S)(μ-S₂)WBr₄] · CH₂Cl₂ · CH₂S. Its IR spectrum is reported, its crystal structure was determined by X-ray diffraction (2330 reflexions, R = 0.097). Crystal data: orthorhombic, Pnma, a = 1 766.5, b = 2 412.7, c = 1 416.3 pm, Z = 4. In the diamagnetic [W₂S₃Br₈]^2? ions the two W atoms are linked via a sulfido and a disulfido bridge and by a W? W bond.