Air‐Stable,Well‐Soluble AI2[Nb6Cl18] Cluster Compounds (AI = Organic Cation): A New Route for Preparation,Single‐Crystal Structures,Properties, and ESI‐Mass Spectra

Five niobium cluster compounds of the A^I₂[Nb₆Cl₁₈] type (A^I = organic cation: [nPr₄N]⁺, [nBu₄N]⁺, [BMIm]⁺, [Ph₄P]⁺, and [PPN]⁺) are obtained through treatment of [Nb₆Cl₁₄(H₂O)₄] · 4H₂O with excess of thionyl chloride in the presence of an organic chloride, A^ICl. Single‐crystal structure studies show that the compounds consist of discrete cations and cluster [Nb₆Cl₁₈]^2– anions. The cluster unit of the hydrated cluster starting material is oxidized by two electrons. Powder diffraction studies and NMR spectroscopic measurements show all compounds to crystallize without co‐crystallized solvent molecules. They are air and water stable. The solubility in organic solvents changes to a great extent on changing the type of cation. The ESI‐MS spectra of [nPr₄N]₂[Nb₆Cl₁₈] and [Ph₄P]₂[Nb₆Cl₁₈] show the pseudomolecular peak of the anionic cluster as well as additional signals, which involve simultaneously chloride mass loss and reduction processes.     

Synthesis and structures of new niobium cluster compounds with pyridinium cations: (PyrH)2[Nb6Cl18]·EtOH (Pyr: pyridine, Et: ethyl) and the cubic modification of (PyrH)2[Nb6Cl18]

Slow crystallization of (PyrH)₂[Nb₆Cl₁₈] from hot ethanol solution affords triclinic (PyrH)₂[Nb₆Cl₁₈]·EtOH. Treatment of [Nb₆Cl₁₄(H₂O)₄]·4H₂O with pyridine in a methanol solution gives the second title compound, the cubic modification of (PyrH)₂[Nb₆Cl₁₈]. Both structures were determined by single crystal X-ray diffraction, (PyrH)₂[Nb₆Cl₁₈]·EtOH: P1¯, a=9.3475(3), b=9.3957(3), c=10.8600(3) Å, α=82.582(1)°, β=78.608(1)°, and γ=78.085(1)°, Z=1, R₁(F)/wR₂(F²)=0.0254/0.0573, cub.-(PyrH)₂[Nb₆Cl₁₈]: Fd3¯m, a=19.935(2) Å, Z=8, R₁(F)/wR₂(F²)=0.0557/0.1796. The cluster compounds contain isolated, molecular [Nb₆Clⁱ₁₂Cl^a₆]²⁻ cluster anions with an octahedron of metal atoms edge bridged by chlorido ligands with additional ones on all the six exo positions. These cluster anions are separated by the pyridinium cations and ethanol solvent molecules, respectively. For the cubic modification of (PyrH)₂[Nb₆Cl₁₈], a structural comparison is given to the known rhombohedral modification using the group-subgroup relations as expressed by a Bärnighausen tree.     

Hexanuclear Niobium Cluster Complex Anions with Acetato Ligands on Intramolecular Bridging Sites: [Nb6Cli4(OAc)i8Cla6]2– and [Nb6(OAc)i12Cla6]2–

From the reaction of [Nb₆Cl₁₄(H₂O)₄] · 4H₂O with acetic anhydride in the presence of an excess of (nBu₄N)F the novel cluster compounds (nBu₄N)₂[Nb₆Clⁱ₄(OAc)ⁱ₈Cl^a₆] ( 1 ) and (nBu₄N)₂[Nb₆(OAc)ⁱ₁₂Cl^a₆] ( 2 ) (OAc = acetato ligand) are obtained. They are the first examples of hexanuclear niobium cluster compounds with acetato ligands on the inner sites of the metal atom octahedron. The crucial role of the presence of fluoride ions in the synthesis is discussed. Each acetato ligand bridges in a μ₂-η¹-fashion with one O atom an edge of the metal atom octahedron. The monoclinic crystals of 1 consist of discrete (nBu₄N)⁺ cations and [Nb₆Clⁱ₄(OAc)ⁱ₈Cl^a₆]^2– cluster anions. They are oxidized by two electrons with respect to the cluster starting material. Besides the syntheses of 1 and 2 , the structure of 1 and spectral properties of both compounds are reported.     

K2SrNb6Cl18, dipotassium strontium hexaniobium octadecachloride

The structure of dipotassium strontium hexaniobium octadeca­chloride is based on [Nb₆Clⁱ₁₂Cl^a₆]^4? units (i and a denote `inner' and `outer' ligands, respectively), which have crystallographically imposed symmetry, linked together by K⁺ and Sr²⁺ cations. The K⁺ cation occupies a tetrahedral site in the face‐centered cubic lattice of cluster units, and is bonded to 12 Cl ligands. The Sr atom is located in an octahedral site and is bonded to six outer Cl ligands.     

Cluster Compounds with Oxidised,Hexanuclear [Nb6Cli12Ia6]n− Anions (n=2 or 3)

Four mixed-halide cluster salts with chloride-iodide-supported octahedral Nb₆ metal atoms cores were prepared and investigated. The cluster anions have the formula [Nb₆Clⁱ₁₂I^a₆]ⁿ⁻ with Cl occupying the inner ligand sites and I the outer one. They are one- or two-electron-oxidized (n=2 or 3) with respect to the starting material cluster. (Ph₄P)⁺ and (PPN)⁺ function as counter cations. The X-ray structures reveal a mixed occupation of the outer sites for only one compound, (PPN)₃[Nb₆Clⁱ₁₂I^a_5.047(9)Cl^a_0.953]. All four compounds are obtained in high yield. If in the chemical reactions a mixture of acetic anhydride, CH₂Cl₂, and trimethylsilyl iodide is used, the resulting acidic conditions lead to form the two-electron-oxidised species (n=2) with 14 cluster-based electrons (CBEs). If only acetic anhydride is used, the 15 CBE species (n=3) is obtained in high yield. Interesting intermolecular bonding is found in (Ph₄P)₂[Nb₆Clⁱ₁₂I^a₆] ⋅ 4CH₂Cl₂ with I⋅⋅⋅I halogen bonding and π-π bonding interactions between the phenyl rings of the cations in (PPN)₃[Nb₆Clⁱ₁₂I^a_5.047(9)Cl^a_0.953]. The solubility of (Ph₄P)₂[Nb₆Clⁱ₁₂I^a₆] ⋅ 4CH₂Cl₂ has been determined qualitatively in a variety of solvents, and good solubility in the aprotic solvents CH₃CN, THF and CH₂Cl₂ has been found.     

New Cluster Complexes with Octahedral Cores of Niobium Atoms: Syntheses, Structures, and Properties of [K(18-crown-6)]2[K(18-crown-6)(H2O)2]2[Nb6Cl12(CN)6] · 2CH3CN and [(C6H5)4P]4[Nb6Cl12(NCS)6] · 0.94CH3OH

The syntheses and structures of [K(18-crown-6)]₂[K(18-crown-6)(H₂O)₂]₂[Nb₆Cl₁₂(CN)₆] · 2CH₃CN (1) and [(C₆H₅)₄P]₄[Nb₆Cl₁₂(NCS)₆] · 0.94CH₃OH (2), determined by X-ray single crystal diffraction, are reported. Crystal data: [K(18-crown-6)]₂[K(18-crown-6)(H₂O)₂]₂[Nb₆Cl₁₂(CN)₆] · 2CH₃CN: monoclinic, P2₁/n, a = 17.8240(9), b = 15.9395(8), c = 18.660(1) Å, β = 113.833(2)°, Z = 2; [(C₆H₅)₄P]₄[Nb₆Cl₁₂(NCS)₆] · 0.94CH₃OH: triclinic, $ P\bar{1} $ , a = 14.6239(3), b = 14.6237(5), c = 15.9831(3) Å, α = 113.482(1)°, β = 114.684(1)°, γ = 92.585(1)°, Z = 1. Both complexes contain [Nb₆Cl₁₂ Y ₆]^4? cluster anions with Y = CN and NCS, respectively, on all six cluster exo-positions. They have been prepared via ligand substitution in solution, starting from K₄[Nb₆Cl₁₈], which was synthesized by a high temperature solid state reaction. Structural trends and spectroscopic properties are discussed and compared to related compounds reported previously in the literature.     

Potassium yttrium hexaniobium octadecachloride,KYNb6Cl18

The structure of potassium yttrium hexaniobium octadeca­chloride is built of anionic [Nb₆Cl₁₂ⁱCl₆^a]⁴⁻ cluster units (where `i' and `a' denote inner and outer ligands, respectively), linked together by K⁺ and Y³⁺ cations. The K⁺ cations occupy half of the tetrahedral vacancies in the face‐centered cubic lattice of cluster units, and are coordinated by 12 chloride ligands. The Y atom is located in an octahedral site and is bonded to six outer chloride ligands.     

Octahedral Niobium Thiocyanato Complexes Containing [Nb6Cl9O3] Cluster Core: Syntheses, Crystal Structures and Evidences of NCS Ligand Exchange

Two isomers (cis and trans) of [Nb₆Cl₉O₃(NCS)₆]^5– niobium cluster complexes characterized by an ordered arrangement of oxygen and chlorine ligands over the 12 inner positions in the cluster core were prepared by reaction of Cs₂LaNb₆Cl₁₅O₃ and ScNb₆Cl₁₃O₃ solid state compounds with aqueous solution of potassium thiocyanate. The cis and trans isomers (idealized C _{2 v} and D ₃ symmetry, respectively) crystallize with counter cations and water molecules to form the following salts: Cs_4.75K_0.25[Nb₆Cl₉O₃(NCS)₆] · 5.5H₂O (1) and Cs_2.5K_2.5[Nb₆Cl₉O₃(NCS)₆] · 2H₂O (2), respectively. The trans isomer is ordered in structure 1 (s.g.: C2/c), while in the structure of 2 (s.g.: Pnma), the cis isomer is randomly disordered over two positions that correspond one to each other by a mirror plane. Interestingly, the treatment of thiocyanato complexes cis and trans with hydrochloric acid led to substitution of (NCS)^– ligands by Cl^– and to formation of soluble complexes [Nb₆Cl₉O₃Cl₆]^5–. The cesium salt of trans-[Nb₆Cl₉O₃Cl₆]^5– was crystallized as Cs₅[Nb₆Cl₁₅O₃] · CsCl · 7H₂O (3) and structurally characterized. Indeed, the formation of soluble [Nb₆Cl₉O₃(NCS)₆]^5– intermediates is a necessary step towards the formation of soluble anions.     

Über Thallium(I)-chlorooxomolybdate: Synthese und Kristallstrukturen von Tl[MoOCl4(NCCH3)], Tl[Mo2O2Cl7] und Tl2[Mo4O4Cl14] und die Struktur von Tl2[MoCl6]

On Thallium(I)-oxochloromolybdates: Synthesis and Crystal Structures of Tl[MoOCl₄(NCCH₃)], Tl[Mo₂O₂Cl₇], and Tl₂[Mo₄O₄Cl₁₄] and the Structure of Tl₂[MoCl₆] Black crystals of Tl₂[MoCl₆] are formed in the reaction of TlCl with MoOCl₃ in a sealed evacuated glass ampoule at 350 °C. The crystal structure analysis shows that Tl₂[MoCl₆] (cubic, Fm 3¯m, a = 986.35(7) pm) adopts the K₂[PtCl₆] structure with a Mo–Cl bond length of 236.6 pm. Tl[MoOCl₄(NCCH₃)] was obtained by the reaction of TlCl with MoOCl₃ in acetonitrile in form of yellow, moisture sensitive crystals. The structure (orthorhombic, Cmcm, a = 746.0(1), b = 1463.8(3), c = 857.3(2) pm) is built of Tl⁺ cations and octahedral [MoOCl₄(NCCH₃)]^– anions in which the acetonitrile ligand is bound in trans position to the oxygen. The reaction of TlCl and MoOCl₃ in dichloromethane yields Tl[Mo₂O₂Cl₇] and Tl₂[Mo₄O₄Cl₁₄] as green moisture sensitive crystals. The structure of Tl[Mo₂O₂Cl₇] (orthorhombic, Pmmn, a = 694.3(1), b = 951.9(2), c = 904.7(1) pm) consists of Tl⁺ cations and dinuclear [Mo₂O₂Cl₇]^– anions, with two equidistant chlorine bridges of 248.2 and one longer chlorine bridge of 265.7 pm. The oxygen atoms are located in the trans positions of the longer chloro bridge. The structure of Tl₂[Mo₄O₄Cl₁₄] (triclinic, P1¯, a = 692.8(1), b = 919.6(1), c = 998.9(1) pm, α = 104.94(1)°, β = 90.31(1)°, γ = 108.14(1)°) is build of Tl⁺ cations and [Mo₄O₄Cl₁₄]^2– anions which form tetramers of distorted octahedral, edgesharing (MoOCl₅) units with chlorine atoms in the bridging positions. The oxygen atoms are located in the trans positions of the longest chlorine bridges.     

Rb6LiPr11Cl16[SeO3]12: Ein chloridisch derivatisiertes Rubidium‐Lithium‐Praseodym(III)‐Oxoselenat(IV)

Rb₆LiPr₁₁Cl₁₆[SeO₃]₁₂: A Chloride‐Derivatized Rubidium Lithium Praseodymium(III) Oxoselenate(IV) Transparent green square platelets with often truncated edges and corners of Rb₆LiPr₁₁Cl₁₆[SeO₃]₁₂ were obtained by the reaction of elemental praseodymium, praseodymium(III,IV) oxide and selenium dioxide with an eutectic LiCl–RbCl flux at 500 °C in evacuated silica ampoules. A single crystal of the moisture and air insensitive compound was characterized by X‐ray diffraction single‐crystal structure analysis. Rb₆LiPr₁₁Cl₁₆[SeO₃]₁₂ crystallizes tetragonally in the space group I4/mcm (no. 140; a = 1590.58(6) pm, c = 2478.97(9) pm, c/a = 1.559; Z = 4). The crystal structure is characterized by two types of layers parallel to the (001) plane following the sequence 121′2′1. Cl^? anions form cubes around the Rb⁺ cations (Rb1 and Rb2; CN = 8; d(Rb⁺?Cl^?) = 331 – 366 pm) within the first layer. One quarter of the possible places for Rb⁺ cations within this CsCl‐type kind of arrangement is not occupied, however the Cl^? anions of these vacancies are connected to Pr³⁺ cations (Pr4) above and below instead, forming square antiprisms of [(Pr4)O₄Cl₄]^9? units (d(Pr4?O) = 247–249 pm; d(Pr4?Cl) = 284–297 pm) that work as links between layer 1 and 2. Central cations of the second layer consist of Li⁺ and Pr³⁺. While the Li⁺ cations are surrounded by eight O^2? anions (d(Li?O5) = 251 pm) in the shape of cubes again, the Pr³⁺ cations are likewisely coordinated by eight O^2? anions as square antiprisms (for Pr1, d(Pr1?O2) = 242 pm) and by ten O^2? anions (for Pr2 and Pr3), respectively. The latter form tetracapped trigonal antiprisms (Pr2, d(Pr2?O) = 251–253 pm and 4 × 262 pm) or bicapped distorted cubes (Pr3, d(Pr3?O) = 245–259 pm and 2 × 279 pm). The non‐binding electron pairs (“lone pairs”) at the two crystallographically different Ψ¹‐tetrahedral [SeO₃]^2? anions (d(Se⁴⁺?O^2?) = 169–173 pm) are directing towards the empty cavities between the layer‐connecting [(Pr4)O₄Cl₄]^9? units.     

Berberine formate–succinic acid (1/1)

The title compound [systematic name: 9,10‐di­methoxy‐2,3‐methyl­ene­dioxy‐5,6‐di­hydro­dibenzo­[a,g]­quinolizinium form­ate–succinic acid (1/1)], C₂₀H₁₈NO₄⁺·CHO₂⁻·C₄H₆O₄, con­tains centrosymmetric pairs of almost planar berberine cations, and hydrogen‐bonded (C₄H₆O₄⋯HCOO⁻)₂ rings of succinic acid with formate anions, bonded by O—H⋯O hydrogen bonds with O⋯O distances of 2.4886 (15) and 2.5652 (16) Å. Pairs of cations and mol­ecules of succinic acid are connected by non‐conventional weak C—H⋯O hydrogen bonds, with C⋯O distances of 3.082 (2) and 3.178 (2) Å.     

Synthesen,Eigenschaften und Kristallstrukturen der Cluster‐Salze Bi6[PtBi6Cl12] und Bi2/3[PtBi6Cl12]

Syntheses, Properties and Crystal Structures of the Cluster Salts Bi₆[PtBi₆Cl₁₂] and Bi_2/3[PtBi₆Cl₁₂] Melting reactions of Bi with Pt and BiCl₃ yield shiny black, air insensitive crystals of the subchlorides Bi₆[PtBi₆Cl₁₂] and Bi_2/3[PtBi₆Cl₁₂]. Despite the substantial difference in the bismuth content the two compounds have almost the same pseudo‐cubic unit cell and follow the structural principle of a CsCl type cluster salt. Bi₆[PtBi₆Cl₁₂] consists of cuboctahedral [PtBi₆Cl₁₂]^2? clusters and Bi₆²⁺ polycations (a = 9.052(2) Å, α = 89.88(2)°, space group P 1, multiple twins). In the electron precise cluster anion, the Pt atom (18 electron count) centers an octahedron of Bi atoms whose edges are bridged by chlorine atoms. The Bi₆²⁺ cation, a nido cluster with 16 skeletal electrons, has the shape of a distorted octahedron with an opened edge. In Bi_2/3[PtBi₆Cl₁₂] the anion charge is compensated by weakly coordinating Bi³⁺ cations which are distributed statistically over two crystallographic positions (a = 9.048(2) Å, α = 90.44(3)°, space group ). Bi₆[PtBi₆Cl₁₂] is a semiconductor with a band gap of about 0.1 eV. The compound is diamagnetic at room temperature though a small paramagnetic contribution appears towards lower temperature.     

Das Lanthan‐Dodekahydro‐closo‐Dodekaborat‐Hydrat [La(H2O)9]2[B12H12]3·15 H2O und sein Oxonium‐Chlorid‐Derivat [La(H2O)9](H3O)Cl2[B12H12]·H2O

The Lanthanum Dodecahydro‐closo‐Dodecaborate Hydrate [La(H₂O)₉]₂[B₁₂H₁₂]₃·15 H₂O and its Oxonium‐Chloride Derivative [La(H₂O)₉](H₃O)Cl₂[B₁₂H₁₂]·H₂O By neutralization of an aqueous solution of the free acid (H₃O)₂[B₁₂H₁₂] with basic La₂O₃ and after isothermic evaporation colourless, face‐rich single crystals of a water‐rich lanthanum(III) dodecahydro‐closo‐dodecaborate hydrate [La(H₂O)₉]₂[B₁₂H₁₂]₃·15 H₂O are isolated. The compound crystallizes in the trigonal system with the centrosymmetric space group (a = 1189.95(2), c = 7313.27(9) pm, c/a = 6.146; Z = 6; measuring temperature: 100 K). The crystal structure of [La(H₂O)₉]₂[B₁₂H₁₂]₃·15 H₂O can be characterized by two of each other independent, one into another posed motives of lattice components. The [B₁₂H₁₂]²⁻ anions (d(B–B) = 177–179 pm; d(B–H) = 105–116 pm) are arranged according to the samarium structure, while the La³⁺ cations are arranged according to the copper structure. The lanthanum cations are coordinated in first sphere by nine oxygen atoms from water molecules in form of a threecapped trigonal prism (d(La–O) = 251–262 pm). A coordinative influence of the [B₁₂H₁₂]²⁻ anions on La³⁺ has not been determined. Since “zeolitic” water of hydratation is also present, obviously the classical H–O^δ–···^+δH–O‐hydrogen bonds play a significant role in the stabilization of the crystal structure. During the conversion of an aqueous solution of (H₃O)₂[B₁₂H₁₂] with lanthanum trichloride an anion‐mixed salt with the composition [La(H₂O)₉](H₃O)Cl₂[B₁₂H₁₂]·H₂O is obtained. The compound crystallizes in the hexagonal system with the non‐centrosymmetric space group (a = 808.84(3), c = 2064.51(8) pm, c/a = 2.552; Z = 2; measuring temperature: 293 K). The crystal structure can be characterized as a layer‐like structure, in which [B₁₂H₁₂]²⁻ anions and H₃O⁺ cations alternate with layers of [La(H₂O)₉]³⁺ cations (d(La–O) = 252–260 pm) and Cl⁻ anions along [001]. The [B₁₂H₁₂]²⁻ (d(B–B) = 176–179 pm; d(B–H) = 104–113 pm) and Cl⁻ anions exhibit no coordinative influence on La³⁺. Hydrogen bonds are formed between the H₃O⁺ cations and [B₁₂H₁₂]²⁻ anions, also between the water molecules of [La(H₂O)₉]³⁺ and Cl⁻ anions, which contribute to the stabilization of the crystal structure.     

Synthese und Struktur der Kronenetherkomplexe von Kaliumhexachlorodipalladat(II) und -diplatinat(II)

Synthesis and Structure of Crown Ether Complexes of Potassium Hexachlorodipalladate(II) and -diplatinate(II) K₂[MCl₄] (M ? Pd, Pt) reacts with an excess of crown ether 18-crown-6 in water to give the crown ether complexes of potassium hexachlorodipalladate(II) and -diplatinate(II) [K(18-cr-6)]₂[M₂Cl₆] (M ? Pd, 1 ; M ? Pt, 3 ), respectively, and in methylene chloride to give those of potassium tetrachloropalladate(II) and -platinate(II) [K(18-cr-6)]₂[MCl₄] ( 1 ) (M ? Pd, 2 ; M ? Pt, 4 ), respectively. 1 - 4 are characterized by microanalysis, NMR (¹H, ¹³C), and vibrational spectroscopy. The X-ray structure analyses of the isotypic complexes 1 (P2₁/c; a = 10,9678(8), b = 8,2991(7), c = 22,469(2) Å, β = 98,523(5)°; Z = 2) and 3 (P2₁/c; a = 10,934(3), b = 8.376(3), c = 22,410(5) Å, β = 98,77(3)°; Z = 2) reveal [M₂Cl₆]^2? anions of nearly D_2h symmetry and [K(18-cr-6)]⁺ cations, in which the distance of K⁺ to the mean plane of the crown ether defined by its six oxygen atoms amounts to 0,830(4) Å in 1 and 0,821(2) Å in 3 , respectively. There are tight contacts between cations and anions (d(K-Cl): 3,341(2)/3,260(2) Å ( 1 ); 3,348(4)/3,259(4) Å ( 3 )).     

Reactions of Chalcogen Oxide Chlorides EOCl2 (E = S,Se) with Group 5 Metal Chlorides

The tantalum derivative TaCl₅(SOCl₂), thermally unstable above 290 K, was prepared from Ta₂Cl₁₀ and SOCl₂ and studied by X‐ray crystallography at 180 K. Tantalum atom is octahedrally coordinated by five chlorides at Ta–Cl distances comprised between 2.32 and 2.36 Å and by the oxygen atom of SOCl₂ at the Ta–O distance of 2.34 Å. No evidence for the existence of an analogous compound of niobium(V) has been obtained. The halides of Group 5, M₂Cl₁₀, M = Nb, Ta, react with SeOCl₂ to give the solid adducts MCl₅(SeOCl₂) stable at room temperature. The reaction of NbCl₅(SeOCl₂) with SOCl₂ affords [SeCl₃][NbCl₆] which contains trigonal‐pyramidal (SeCl₃)⁺ cations with Se–Cl distances of 2.13–2.16 Å and octahedral [NbCl₆]^– anions (Nb–Cl: 2.27–2.45 Å). A distorted octahedral coordination around the selenium atom is achieved by additional interactions [Se…Cl, 2.81–2.98 Å] between selenium and the [NbCl₆]^– anion.     

Thiocyanate Compounds of [Nb6Cl12]2+: The structure of A4[Nb6Cl12(NCS)6](H2O)4 (A = K,Rb, NH4)

New compounds of the general formula A₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ (A = K, Rb, NH₄) were synthesized from Nb₆Cl₁₄ and ASCN in aqueous solutions. X-ray structure refinements were performed on single-crystal data of the three compounds. They are isotypic and crystallize with the space group P1 (Z = 1) and the lattice parameters: a = 877.9(3) pm, b = 1176.6(3) pm, c = 1187.0(3) pm, α = 114.29(1)°, β = 98.96(2)°, γ = 100.91(2)° for K₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 1 ); a = 887.6(3) pm, b = 1184.0(4) pm, c = 1195.4(4) pm, α = 114.95(2)°, β = 98.84(2)°, γ = 101.31(2)° for Rb₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 2 ) and a = 886.0(4) pm, b = 1181.1(6) pm, c = 1183.9(6) pm, α = 114.49(2)°, β = 99.48(3)°, γ = 101.53(1)° for (NH₄)₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 3 ). Each centrosymmetric [Nb₆Cl₁₂(NCS)₆]^4? ion of the isotypic compounds contains six terminal thiocyanate groups being bound to the corners of the octahedral niobium cluster through the nitrogen atoms (d_{Nb? N} = 221.5(6)–224.3(6) pm, bond angles Nb? N? C 168.6(5)–176.4(6)°). The [Nb₆Cl₁₂(NCS)₆]^4? ions are linked via A? S and A? Cl interactions with the A cations. Half of the cations occur to be disordered along two crystallographic sites.     

Room-Temperature Synthesis of the Bi5[GaCl4]3 Salt From Three Different Classes of Ionic Liquids

Following the development in the synthesis of subvalent cluster compounds, we report on the use of three different classes of room-temperature ionic liquids for the synthesis of the pentabismuth-tris(tetragallate) salt, Bi₅[GaCl₄]₃, characterized by X-ray diffraction. The Bi₅[GaCl₄]₃ salt was prepared by reduction of BiCl₃ using gallium metal in ionic liquid reaction media containing a strong Lewis acid, GaCl₃. The ionic liquids; trihexyltetradecyl phosphonium chloride [Th-Td-P⁺]Cl^?, 1-dodecyl-3-methylimidazolium chloride [Dod-Me-Im⁺]Cl^? and N-butyl-N-methylpyrrolidinium chloride [Bu-Me-Pyrr⁺]Cl^? from three of the main classes of ionic liquids were used in synthesis. Reactions using ionic liquids composed of the trihexyltetradecyl phosphonium cation [Th-Td-P⁺] and the anions; tetrafluoroborate [BF₄ ^?], bis(trifluoro-methyl sulfonyl) imide [(Tf)₂N^?] and hexafluorophosphate [PF₆ ^?] were also investigated.     

Compounds with Cluster Cations together with Cluster Anions [(M6X12)(EtOH)6]2+ besides [(Mo6Cl8)Cl4X2]2– (M = Nb,Ta; X = Cl,Br) – Synthesis and Crystal Structures

Compounds consisting of both cluster cations and cluster anions of the composition [(M₆X₁₂)(EtOH)₆][(Mo₆Cl₈)Cl₄X₂] · n EtOH · m Et₂O (M = Nb, Ta; X = Cl, Br) have been prepared by the reaction of (M₆X₁₂)X₂ · 6 EtOH with (Mo₆Cl₈)Cl₄. IR data are given for three compounds. The structures of [(Nb₆Cl₁₂)(EtOH)₆][(Mo₆Cl₈)Cl₆] · 3 EtOH · 3 Et₂O 1 and [(Ta₆Cl₁₂)(EtOH)₆][(Mo₆Cl₈)Cl₆] · 6 EtOH 2 have been solved in the triclinic space group P1 (No. 2). Crystal data: 1 , a = 10.641(2) Å, b = 13.947(2) Å, c = 15.460(3) Å, α = 65.71(2)°, β = 73.61(2)°, γ = 85.11(2)°, V = 2005.1(8) ų and Z = 1; 2 , a = 11.218(2) Å, b = 12.723(3) Å, c = 14.134(3) Å, α = 108.06(2)°, β = 101.13(2)°, γ = 91.18(2)°, V = 1874.8(7) ų and Z = 1. Both structures are built of octahedral [(M₆Cl₁₂)(EtOH)₆]²⁺ cluster cations and [(Mo₆Cl₈)Cl₆]^2– cluster anions, forming distorted CsCl structure types. The Nb–Nb and Ta–Ta bond lengths of 2.904 Å and 2.872 Å (mean values), respectively, are rather short, indicating weak M–O bonds. All O atoms of coordinated EtOH molecules are involved in H bridges. The Mo–Mo distances of 2.603 Å and 2.609 Å (on average) are characteristic for the [(Mo₆Cl₈)Cl₆]^2– anion, but there is a clear correlation between the number of hydrogen bridges to the terminal Cl and the corresponding Mo–Cl distances.     

Crystal Structure of (H3O)4[(C2H5)4N]6 [Th2Cl4(H2O)12O]3[Re4Se4(CN)12]4

Crystals of the rhenium cluster complex (H₃O)₄[(C₂H₅)₄N]₆[Th₂Cl₄(H₂O)₁₂O]₃[Re₄Se₄(CN)₁₂]₄ are obtained in an acidic (HCl) aqueous solution by the reaction of cluster salt K₄[Re₄Se₄(CN)₁₂]·6H₂O with ThCl₄ and (C₂H₅)₄NCl. Single crystal X-ray analysis shows that the title compound is ionic and crystallizes in the cubic crystal system (a = 22.7322(3) ?, V = 11746.93(27) ?³, Z = 2, I4 3m space group, R = 0.0350). It contains [Th₂Cl₄(H₂O)₁₂O]²⁺ cations with two thorium atoms bonded to each other through the bridging oxygen atom forming an angle of 180° in the structure.     

Beiträge zur Chemie der Elemente Niob und Tantal. 81. Niob- und Tantalkomplexe mit der anionischen Gruppe {[Me6X12]X}; X = Cl,Br

The compounds A₄[Nb₆Cl₁₂]Cl₆ (A ? Na, K, Cs), K₄[Nb₆Br₁₂]Br₆ and A₄[Ta₆Cl₁₂]Cl₆ (A ? Na, K, Cs) are prepared. The chemical equations for formation and decomposition are taken into consideration. The complexes [Nb₆Br₁₂]²⁺ and [Ta₆Cl₁₂]²⁺, unstable in the binary systems, are stabilized in the ternary compounds. The compounds are isotypic with the known K₄[Nb₆Cl₁₂]Cl₆. For some of them lattice constants and molecular volumes are communicated.