Syntheses and crystal structures of the first organically templated metal tellurites

The first organically templated vanadium tellurites, [H₂en][(VO₂)(TeO₃)]₂·H₂O (1, en=ethylenediamine) and [H₂pip][(VO₂)(TeO₃)]₂ (2, pip=piperazine) have been synthesized by hydrothermal reactions and structurally characterized. Both compounds feature a [(VO₂)(TeO₃)]⁻ anionic layer containing V₂Te₂ four-member rings and V₄Te₄ eight member rings. The vanadium (V) atom is five coordinated by three tellurite oxygens and two terminal oxygen atoms in a distorted trigonal bipyramidal geometry. The interconnection of the VO₅ polyhedra by bridging tellurite groups leads to a 2D corrugated anionic inorganic layer. The doubly protonated template cations and the lattice water molecules in 1 are located at the interlayer space and are involved in hydrogen bonding. The doubly protonated template cation in 2 is not involved in hydrogen bonding with the anionic inorganic layer.     

A new one‐dimensional strontium vanadium tellurite,Sr7V4Te12O41

Vanadium tellurites display a rich structural chemistry with interesting physical properties, such as second harmonic generation (SHG). Tellurites, i.e. Te⁴⁺O_x, are often observed in unusual structures and form various structural motifs, including isolated clusters, chains, layers, and three‐dimensional networks. Similarly, vanadates, i.e. V⁵⁺O_x, show rich structural features, such as VO₄ tetrahedra, VO₅ square pyramids or trigonal bipyramids, and VO₆ octahedra. Strontium vanadium tellurite, Sr₇V₄Te₁₂O₄₁, was obtained from the melt of the solid‐state reaction of SrTeO₄ and VO₂ in a sealed quartz tube as it cooled from 973 K. The crystal structure exhibits a one‐dimensional latticework along the a axis comprised of paired Sr₃Te₃O_x units, namely Sr₆Te₆O_2x+1, with corner‐shared TeO₄ polyhedra – and specifically the Te lone‐pair electrons – facing outward in the bc plane. The Sr₆Te₆O_2x+1 latticework is helical and is layered in the b‐axis direction against sheets of corner‐shared VO₄ tetrahedra, and is linked in the c‐axis direction via individual corner‐shared SrO₈ square prisms.     

Narrow Band Gap Compounds with β-Pyrochlore Structure in the A2O-V2O5-2TeO3 (A=Rb,Cs) System

Two new isostructural compounds with composition of Rb⁺V³⁺_0.125V⁵⁺_0.625Te⁶⁺_1.25O₆ and Cs⁺V³⁺_0.125V⁵⁺_0.625Te⁶⁺_1.25O₆ have been synthesized by solid-state reaction. The crystal structure has been determined by X-ray diffraction analysis using Rietveld refinement. Both compounds possess β-pyrochlore structure-type with cubic space group Fd-3 m (Z=8); the unit cell parameters: a=10.04120(27) Å for RbV_0.75Te_1.25O₆ Å and a=10.09119(23) Å for CsV_0.75Te_1.25O₆. The oxidation states of vanadium and tellurium have been confirmed by X-ray photoelectron spectroscopy. The compounds contain vanadium in mixed valence state (3+ and 5+). The compounds possess the unusual narrow band gap for oxide compounds – in the infrared (IR) range (∼0.6 eV). The schematic electronic structure of the compounds has been estimated using XPS, UPS and electronic conductivity data; however, the shifts of the top of the valence edge and the bottom of the conduction band in the water conditions have been calculated using theoretical approximation. The thermal behavior of obtained compounds has been studied by differential thermal analysis. RbV_0.75Te_1.25O₆ and CsV_0.75Te_1.25O₆ melts at low temperatures (∼500 °C) with decomposition and weight loss. The RbV_0.75Te_1.25O₆ powder decomposes to amorphous phase, whereas CsV_0.75Te_1.25O₆ transform into new β-pyrochlore compound with another composition.     

The Crystal Structures and Raman Spectra of Three New Hydrothermally Synthesized Copper–Zinc–Oxotellurates(IV)

Abstract . Three new copper–zinc–tellurites, Zn₄Cu(Te^IVO₃)₄Cl₂, Cu₂Zn₂(Te^IVO₃)₂(SO₄)(OH)₂ · H₂O and Cu₂Zn(Te^IVO₄)(SO₄) · H₂O (henceforth I , II and III ), were synthesized under mild hydrothermal conditions (473 K, in Teflon-lined steel vessels). They were characterized in detail by a combination of crystal-structure determination (using single-crystal X-ray diffraction data), single-crystal micro-Raman spectroscopy and chemical analyses (energy-dispersive X-ray spectroscopy in a scanning electron microscope). Each compound crystallizes in a new structure type, and additionally, II and III represent the first two ever reported copper–zinc–tellurite–sulfates. I [systematic name: tetrazinc copper(II) tetrakis-oxotellurate(IV) dichloride] is triclinic, P1 , and forms a framework structure based on ZnO₆ and ZnO₅Cl octahedra, linked into sheets connected via Jahn–Teller-distorted CuO₄Cl₂ octahedra, with Te^IVO₃ trigonal pyramids and Te^IV₂O₆ dimers (composed of two edge-sharing Te^IVO₄ disphenoids) filling the remaining space. II [dicopper(II) dizinc bis-oxotellurate(IV) oxosulfate(VI) bis-hydroxide monohydrate] is trigonal, R3m, with a simonkolleite-like framework. Distinct layers formed from (Cu,Zn)φ₆ (φ = O, OH) octahedra and Te^IVO₃ trigonal pyramids extend parallel to (001) and sandwich disordered SO₄^2– anions and H₂O groups. III [dicopper(II) zinc oxotellurate(IV) oxosulfate(VI) hydrate] is orthorhombic, Pnma, and also has a layered structure [extending parallel to (100)]. Positively charged layers of composition [Cu₂ZnTe^IVO₄]²⁺ (containing Te as Te^IVO₄ disphenoids) alternate with SO₄^2– anions and H₂O groups in the interlayer space. Stacking disorder caused by the order-disorder nature of the crystal structure is reflected by the presence of residual electron density in difference-Fourier maps and the structure was refined as an overlay of two stacking possibilities.     

Hydrothermal synthesis and characterization of two new layered vanadium tellurites Cu(TATP)V2TeO8 and Cu(DPPZ)V2Te2O10

Two new vanadium tellurites, Cu(TATP)V₂TeO₈ (1) and Cu(DPPZ)V₂Te₂O₁₀ (2), (TATP=1,4,8,9-tetranitrogen-trisphene, DPPZ=dipyridophenazine) have been synthesized under hydrothermal conditions and structurally characterized by elemental analyses, IR, and single-crystal X-ray diffraction. Compound 1 features an interesting two-dimensional layer structure constructed by [V₂TeO₈]_n double-chain-like ribbons linked by [Cu(TATP)]²⁺ bridges. Compound 2 consists of two types of chiral layers: one left-handed and the other right-handed, which lead to racemic solid-state compound. In each layer, there exist two types of inorganic helical chains (V₄Te₄O₈)_n and (Te₂O₂)_n, with same handedness. Two types of helical chains are linked by μ₃(O6) atoms to generate a V/Te/O inorganic anionic layer. The [Cu(DPPZ)]²⁺ cationic complex fragments are covalently bonded to the layer, projecting below and above the vanadium tellurites layer.     

[R-C7H16N2][V2Te2O10] and [S-C7H16N2][V2Te2O10]; new polar templated vanadium tellurite enantiomers

New polar vanadium tellurite enantiomers have been synthesized under mild hydrothermal conditions through the use of sodium metavanadate, sodium tellurite and enantiomerically pure sources of either R-3-aminioquinuclidine or S-3-aminioquinuclidine. [R-C₇H₁₆N₂][V₂Te₂O₁₀] and [S-C₇H₁₆N₂][V₂Te₂O₁₀] contain [V₂Te₂O₁₀]_n²ⁿ⁻ layers constructed from [(VO₂)₂O(TeO₄)₂] monomers. Steric effects associated with the hydrogen-bonding network between the [V₂Te₂O₁₀]_n²ⁿ⁻ layers and [C₇H₁₆N₂]²⁺ result in polar structures and crystallization in the space group P2₁ (no. 4). Electron localization functions were calculated to visualize the tellurite stereoactive lone pairs. Both iterative and non-iterative Hirshfeld techniques were evaluated as means to determine atomic partial charges, with iterative Hirshfeld charges more accurately representing charge distributions in the reported enantiomers. These charges were used to calculate both component and net dipole moments. [R-C₇H₁₆N₂][V₂Te₂O₁₀] and [S-C₇H₁₆N₂][V₂Te₂O₁₀] exhibit dipole moments of 17.37 and 16.62D, respectively. [R-C₇H₁₆N₂][V₂Te₂O₁₀] and [S-C₇H₁₆N₂][V₂Te₂O₁₀] both display type 1 phase-matching capabilities and exhibit second harmonic generation activities of ∼50×α-SiO₂.     

Modified Tellurium Subhalides in the New Structure Type [Te15X4]n[MOX4]2n (M = Mo,W; X = Cl,Br)

The reactions of Te₂Br with MoOBr₃, TeCl₄ with MoNCl₂/MoOCl₃, and Te with WBr₅/WOBr₃ yield black, needle-like crystals of [Te₁₅X₄][MOX₄]₂ (M = Mo, W; X = Cl, Br). The crystal structure determinations [Te₁₅Br₄][MoOBr₄]₂: monoclinic, Z = 1, C2/m, a = 1595.9(4) pm, b = 403.6(1) pm, c = 1600.4(4) pm, β = 112.02(2)°; [Te₁₅Cl₄][MoOCl₄]₂: C2/m, a = 1535.3(5) pm, b = 402.8(2) pm, c = 1569.6(5) pm, β = 112.02(2)°; [Te₁₅Br₄][WOBr₄]₂: C2, a = 1592.4(4) pm, b = 397.5(1) pm, c = 1593.4(5) pm, β = 111.76(2)° show that all three compounds are isotypic and consist of one-dimensional ([Te₁₅X₄]²⁺)_n and ([MOX₄]^?)_n strands. The structures of the cationic strands are closely related to the tellurium subhalides Te₂X (X = Br, I). One of the two rows of halogen atoms that bridges the band of condensed Te₆ rings is stripped off, and additionally one Te position has only 75% occupancy which leads to the formula ([Te₁₅X₄]²⁺)_n (X = Cl, Br) for the cation. The anionic substructures consist of tetrahalogenooxometalate ions [MOX₄]^? that are linked by linear oxygen bridges to polymeric strands. The compounds are paramagnetic with one unpaired electron per metal atom indicating oxidation state M^v, and are weak semiconductors.     

Synthese und Kristallstruktur des ionischen Tellurnitridchlorids [Te3N2Cl5(SbCl5)]+SbCl6−

Synthesis and Crystal Structure of the Ionic Tellurium Nitride Chloride[Te₃N₂Cl₅(SbCl₅)]⁺SbCl₆^? The title compound has been prepared by the reaction of Te₂NCl₅ with antimony pentachloride in CH₂Cl₂ suspension. It is characterized by IR spectroscopy and by a crystal structure determination. Space group P2₁/c, Z = 4, lattice dimensions at ?70°C: a = 1535.6, b = 1259.5, c = 1572.4 pm, β = 109.30°, R = 0.031. The compound forms an ionic pair with the central group of a (TeNCl)₂ molecule in which the tellurium atoms are linked by the nitrogen atoms to give a planar Te₂N₂ four-membered ring. One of the nitrogen atoms is coordinated by a TeCl₃⁺ unit, the other one by an antimony pentachloride molecule. According to the IR spectra a structure like [Te₂N₂Cl₂(TeCl₄)₂] is proposed for Te₂NCl₅.     

Solvothermal Synthesis and Crystal Structure of Te8[U2Br10], Containing a Polymeric Chalcogen Cation (Te82+)n

Under solvothermal conditions, the reaction of Te, TeBr₄ and UBr₅ in SiBr₄ at 200?C yields Te₈[U₂Br₁₀] as silvery crystals. The crystal structure (triclinic, P&1macr;, a = 900.8(4), b = 1205.1(5), c = 1366.0(6) pm, α = 80.93(4)?, β = 76.83(3)?, γ = 78.84(3)?, Z = 2) is built of one‐dimensional polymeric (Te₈²⁺)_n cations consisting of boat‐shaped Te₆ rings, which are linked by Te₂ bridges. The anions [U₂Br₁₀^2‐]_n are also polymeric, consisting of edge sharing UBr₇ pentagonal bipyramids [UBr₃Br_4/2^2‐]_n and contain U(IV). Both chains are parallel to each other and run along the crystallographic a‐axis. The cation represents a formerly unknown isomer of Te₈²⁺ ions. So far, Te₈²⁺ has been known as molecular clusters in Te₈[MCl₆](M = Zr, Hf, Re) and (Te₈)(Te₆)[WCl₆]₄, or in form of linked bicyclic monomers that are present in Te₈[WCl₆]₂. A polymeric chain‐like form closely related to Te₈[U₂Br₁₀] was found in Te₈[Bi₄Cl₁₄].     

A square‐planar tellurium(II) complex with Te,Te′‐chelating ligands

While exploring the chemistry of tellurium‐containing dichalcogenidoimidodiphosphinate ligands, the first all‐tellurium member of a series of related square‐planar E^II(E′)₄ complexes (E and E′ are group 16 elements), namely bis(P,P,P′,P′‐tetraphenylditelluridoimidodiphosphinato‐κ²Te,Te′)tellurium(II) (systematic name: 2,2,4,4,8,8,10,10‐octaphenyl‐1λ³,5,6λ⁴,7λ³,11‐pentatellura‐3,9‐diaza‐2λ⁵,4λ⁵,8λ⁵,10λ⁵‐tetraphosphaspiro[5.5]undeca‐1,3,7,9‐tetraene), C₄₈H₄₀N₂P₄Te₅, was obtained unexpectedly. The formally Te^II centre is situated on a crystallographic inversion centre and is Te,Te′‐chelated to two anionic [(TePPh₂)₂N]⁻ ligands in an anti conformation. The central Te^II(Te)₄ unit is approximately square planar [Te—Te—Te = 93.51 (3) and 86.49 (3)°], with Te—Te bond lengths of 2.9806 (6) and 2.9978 (9) Å.     

[K(15-Krone-5)2]2Te8 — ein bicyclisches Polytellurid

[K(15-Crown-5)₂]₂Te₈ – a Bicyclic Polytelluride The octatelluride [K(15-crown-5)₂]₂Te₈ has been synthesized by the oxydation of a potassium tritelluride solution in dimethylformamide by iron(III) chloride in the presence of 15-crown-5, forming black crystals, which were characterized by an X-ray structure determination. Space group Pca2₁, Z = 4, 4 548 observed unique reflections, R = 0.048. Lattice dimensions at –70°C: a = 1 881(1), b = 2 211(2), c = 1 530(1) pm. The structure consists of cations [K(15-crown-5)₂]⁺, in which the potassium ions are sandwichlike coordinated by the oxygen atoms of the two disordered crown ether molecules, and of bicyclic Te₈^2? ions. In these anions a Te²⁺ ion is chelated in a planar fashion by a Te₃^2? and a Te₄^2? unit.     

[Te8][NbOCl4]2 containing an infinite chain‐like {[Te–Te–Te–(Te5)]2+}n polycation

The title compound, [Te₈][NbOCl₄]₂, was obtained as translucent black crystals by reaction of elemental tellurium, niobium(V) chloride and niobium(V) oxychloride in the ionic liquid BMImCl (BMImCl is 1‐butyl‐3‐methylimidazolium chloride). The synthesis was performed in argon‐filled glass ampoules. According to X‐ray structure analysis based on single crystals, the title compound crystallizes with triclinic lattice symmetry and consists of infinite {[Te₈]²⁺}_n cations associated with pyramidal [NbOCl₄]⁻ anions. The novel catena‐octatellurium(2+) cation is composed of Te₅ rings that are linked via Te₃ units [Te—Te = 2.6455 (18)–2.8164 (19) Å]. The composition and purity of [Te₈][NbOCl₄]₂ were further confirmed by energy‐dispersive X‐ray diffraction (EDX) analysis.     

A non‐twinned polymorph of CaTe2O5 from a hydrothermally grown crystal

In contrast with the multiple twinning and/or domain formation found in the mica‐like polymorphs of CaTe₂O₅, calcium pentaoxidoditellurate(IV), that have been prepared by solid‐state reactions and for which complete structure determinations have not been successful up to now, the crystal structure of a hydrothermally grown phase was fully determined from a non‐twinned crystal. The structure is made up of alternating layers of Ca²⁺ cations and of ²_∞[Te₂O₅]²⁻ anions stacked along [100]. The lone‐pair electrons E of the Te^IV atoms are stereochemically active and protrude into channels within the anionic layer. In comparison with analogous M^IITe₂O₅ structures (M = Mg, Mn, Ni or Cu) with ditellurate(IV) anions that are exclusively made up of corner‐sharing TeO_x (x = 3–5) polyhedra resulting in flat ²_∞[Te₂O₅]²⁻ layers, the anionic layers in CaTe₂O₅ are undulating and are built of corner‐ and edge‐sharing [TeO₄] polyhedra.     

A Facile Route for the Synthesis of Polycationic Tellurium Cluster Compounds: Synthesis in Ionic Liquid Media and Characterization by Single‐Crystal X‐ray Crystallography and Magnetic Susceptibility

An innovative soft chemical approach was applied, using ionic liquids as an alternative reaction medium for the synthesis of tellurium polycationic cluster compounds at room temperature. [Mo₂Te₁₂]I₆, Te₆[WOCl₄]₂, and Te₄[AlCl₄]₂ were isolated from the ionic liquid [BMIM]Cl/AlCl₃ ([BMIM]⁺: 1‐n‐butyl‐3‐methylimidazolium) and characterized. Black, cube‐shaped crystals of [Mo₂Te₁₂]I₆, which is not accessible by conventional chemical transport reaction, were obtained by reaction of the elements at room temperature in [BMIM]Cl/AlCl₃. The monoclinic structure (P2₁/n, a = 1138.92(2) pm, b = 1628.13(2) pm, c = 1611.05(2) pm, β = 105.88(1) °) is homeotypic to the triclinic bromide [Mo₂Te₁₂]Br₆. In the binulear complex [Mo₂Te₁₂]⁶⁺, the molybdenum(III) atoms are η⁴‐coordinated by terminal Te₄²⁺ rings and two bridging η²‐Te₂^2– dumbbells. Despite the short Mo···Mo distance of 297.16(5) pm, coupling of the magnetic moments is not observed. The paramagnetic moment of 3.53 μ_B per molybdenum(III) atom corresponds to an electron count of seventeen. Black crystals of monoclinic Te₆[WOCl₄]₂ are obtained by the oxidation of tellurium with WOCl₄ in [BMIM]Cl/AlCl₃. Tellurium and tellurium(IV) synproportionate in the ionic liquid at room temperature yielding violet crystals of orthorhombic Te₄[AlCl₄]₂.     

Catalytic activity of V-substituted Cs2Te0.2H0.6 + xPMo12 ? xVxOn heteropoly compounds in selective oxidation of isobutane

A series of Cs₂Te_0.2H_{0.6 + x} PMo_{12 − x} V _x O _n (x = 0–3) heteropoly compounds has been prepared and tested in the partial oxidation of isobutane. Catalytic tests show that at 350°C very high selectivity to methacrylic acid (60.1%) can be achieved at isobutane conversion of 12.2% over a Cs_2.0Te_0.2H_1.6PMo₁₁VO _n catalyst with only one molybdenum atom per unit cell substituted by vanadium. The presence of Te⁴⁺ in the heteropoly compounds appears to interfere with the dehydrqgenation step and favor the formation of methacrolein and methacrylic acid.     

Polymere,bandförmige Tellurkationen in den Strukturen des Chloroberyllats Te7[Be2Cl6] und des Chlorobismutats (Te4)(Te10)[Bi4Cl16]

Polymeric, Band Shaped Tellurium Cations in the Structures of the Chloroberyllate Te₇[Be₂Cl₆] and the Chlorobismutate (Te₄)(Te₁₀)[Bi₄Cl₁₆] Te₇[Be₂Cl₆] is obtained at 250 °C in an eutectic Na₂[BeCl₄] / BeCl₂ melt from Te, TeCl₄ und BeCl₂ in form of black crystals, which are sensitive towards hydrolysis in moist air. (Te₄) (Te₁₀)[Bi₄Cl₁₆] is prepared from Te, TeCl₄ und BiCl₃ by chemical vapour transport in sealed evacuated glass ampoules in a temperature gradient 150 ° → 90 °Cin form of needle shaped crystals with a silver lustre. The structures of both compounds were determined based on single crystal X‐ray diffraction data (Te₇[Be₂Cl₆]: orthorhombic, Pnnm, Z = 2, a = 541.60(3), b = 974.79(6), c = 1664.4(1) pm; (Te₄)(Te₁₀)[Bi₄Cl₁₆]: triclinic, P1¯, Z = 2, a = 547.2(3), b = 1321.1(7), c = 1490(1) pm, α = 102.09(5)°, β = 95.05(5)°, γ = 96.69(4)°). The structure of Te₇[Be₂Cl₆] consists of one‐dimensional polymeric cations (Te₇²⁺)_n which form folded bands and of discrete [Be₂Cl₆]^2— anions which form double tetrahedraconnected by a common edge. By a different way of folding compared with the cations present in the structures of Te₇[MOX₄]X (M = Nb, W; X = Cl, Br) the (Te₇²⁺)_n cation in Te₇[Be₂Cl₆]represents a new, isomeric form. The structure of (Te₄)(Te₁₀)[Bi₄Cl₁₆] contains two different polymeric cations. (Te₁₀²⁺)_n consists of planar Te₁₀ groups in the form of three corner‐sharing Te₄ rings connected to folded bands. (Te₄²⁺)_n forms in contrast to the so far notoriously observed discrete, square‐planar E₄²⁺ ions a chain of rectangular planar Te₄ rings (Te—Te 274 and 281 pm) connected by Te‐Te bonds of 297 pm. [Bi₄Cl₁₆]^4— has a complex one‐dimensional structure of edge‐ and corner‐sharing BiCl₇ units.     

Molecular building blocks for solid‐state chalcogenides: solvothermal synthesis of [Mn(en)3]Te4 and [Fe(en)3]2(Sb2Se5)

Two new molecular metal chalcogenides, tris­(ethyl­enedi­amine‐N,N′)­manganese(II) tetratelluride, [Mn(C₂H₈N₂)₃]Te₄, (I), and bis­[tris­(ethyl­enedi­amine‐N,N′)­iron(II)] penta­seleno­diantimonate(III), [Fe(C₂H₈N₂)₃]₂(Sb₂Se₅), (II), containing the isolated molecular building blocks Te₄^2? and Sb₂Se₅^4?, have been synthesized by solvothermal reactions in an ethyl­enedi­amine solution at 433 K. The anion Te₄^2? in (I) is a zigzag oligometric chain with Te—Te bond lengths in the range 2.709–2.751 Å. There is a very short contact [3.329 (1) Å] between a pair of neighboring Te₄^2? anions. In (II), each Sb atom is surrounded by three Se atoms to give a tripodal coordination. One of the three independent Se atoms is a μ₂‐bridging ligand between two Sb atoms; the other two are terminal.     

Synthese und Kristallstruktur von Te3O3(PO4)2, einer Verbindung mit fünffach koordiniertem Tellur(IV)

Synthesis and Crystal Structure of Te₃O₃(PO₄)₂, a Compound with 5‐fold Coordinate Tellurium(IV) Polycrystalline Te₃O₃(PO₄)₂ is formed during controlled dehydration of (Te₂O₃)(HPO₄) with (Te₈O₁₀)(PO₄)₄ as an intermediate product. Colourless single crystals were prepared by heating stoichiometric amounts of the binary oxides P₂O₅ und TeO₂ in closed silica glass ampoules at 590 °C for 8 hours. The crystal structure (P2₁/c, Z = 4, α = 12.375(2), b = 7.317(1), c = 9.834(1)Å, β = 98.04(1)°, 1939 structure factors, 146 parameters, R[F² > 2σ(F²)] = 0.0187, wR2(F² all) = 0.0367) was determined from four‐circle diffractometer data and consists of [TeO₅] polyhedra und PO₄ tetrahedra as the main building units. The framework structure is made up of cationic zigzag‐chains of composition [Te₂O₃]²⁺ which extend parallel to [001] and anionic [Te(PO₄)₂]^2— units linked laterally to these chains. This leads to the formation of [Te₂O₃][Te(PO₄)₂] layers parallel to the bc plane which are interconnected via weak Te‐O bonds.     

Hexatellurium Rings in Coordination Polymers and Molecular Clusters: Synthesis and Crystal Structures of [M(Te6)]X3 (M = Rh,Ir; X = Cl,Br, I) and [Ru2(Te6)](TeBr3)4(TeBr2)2

The reaction of an electron‐rich transition metal M (M = Ru, Rh, Ir), tellurium and TeX₄ (X = Cl, Br, I) resulted in black crystals of five ternary coordination polymers with the general composition [M^III(Te₆)]X₃ (M = Rh, Ir) and of the molecular cluster compound [Ru^II₂(Te₆)](Te^IIBr₃)₄(Te^IIBr₂)₂. X‐ray diffraction on single‐crystals revealed that the compounds [M(Te₆)]X₃ crystallize isostructurally in the trigonal space group type R$\bar{3}$ c. In their crystal structures linear, positively charged [M^III(Te₆)] chains form the motif of a hexagonal rod packing. In the chain, each of the formally uncharged Te₆ molecules with chair conformation acts as a bis‐tridentate bridging ligand to two M atoms. The octahedrally coordinated M atoms are spiro atoms in the chain of trans vertices sharing heterocubane fragments. Including the isolated halide ions, which provide charge balance, the entire arrangement resembles a cut‐out of the α‐polonium structure type.In the monoclinic compound Ru₂Te₁₂Br₁₆ (space group P2₁/n), the ruthenium atoms of the hetero‐cubane core of the molecular cluster [Ru₂(Te₆)](TeBr₃)₄(TeBr₂)₂ are saturated by terminal bromidotellurate(II) groups. Again, the Te₆ ring is formally uncharged. With the tellurium atoms acting as electron‐pair donors the 18 electron rule is fulfilled for the M atoms in all compounds.     

Synthese und Kristallstruktur von [Na(15-Krone-5)]4[Cd4Te12] · 8 DMF

Synthesis and Crystal Structure of [Na(15-Crown-5)]₄[Cd₄Te₁₂] · 8 DMF The title compound has been prepared by reaction of Na₂Te₃ with cadmium acetate in DMF solution in the presence of 15-crown-5, forming black crystal needles, which were characterized by an X-ray structure determination. Space group P2₁/n, Z = 2, 5 716 observed unique reflections, R = 0.038. Lattice dimensions at ?50°C: a = 1 622.9, b = 2 038.2, c = 1 739.8 pm, β = 92.26°. The compound has an ionic structure. The cations [Na(15-crown-5)(DMF)]⁺ and [Na(15-crown-5) · (DMF)₂]⁺ together with two further DMF molecules form tetrameric units. In the centrosymmetric anions [Cd₄Te₁₂]^4? the cadmium atoms are linked by μ₂-Te^2?-, μ₄-Te₂^2?-, and μ₂-Te₃^2?-units.