Synthesis and Crystal Structure of Tellurium(II) bis(2‐methoxycarbonylethanethiolate): A Novel Coordination Mode of Tellurium

The tellurium(II) dithiolates Te[SCH₂CH₂C(O)OCH₃]₂, ( 1 ), Te[SCH₂CH₂CH₂SC(O)CH₃]₂, ( 2 ), and Te[SCH₂CH₂CH₂CH₂SC(O)CH₃]₂, ( 3 ) were synthesized from Te(S^tBu)₂ and the corresponding thiol. All compounds are sensitive toward higher temperatures and light and decompose to elemental tellurium and the disulfide. In the solid state, the Te atom of 1 exhibits the novel Te(S₂Te₂) coordination mode. Additionally to the two Te—S bonds, each Te atom forms two long Te···Te contacts to neighboring molecules, leading to a coordination number of four and a distorted sawhorse configuration. No intramolecular Te···O interactions are present in the solid state, in accordance with ab initio calculations (MP2/ecp‐basis) for the isolated molecule. ¹²⁵Te NMR shifts of all compounds lay within a narrow range and close to the respective shift of other Te(SCH₂R)₂ compounds. VT ¹²⁵Te NMR spectra gave no hint to donor acceptor interactions in solution for any of the compounds and thus corroborate results from IR‐spectroscopy, ab initio geometry optimizations, and thermochemical calculations.     

Synthesis and Crystal Structure of >Bis(tetrapropylammonium) Hexabromotellurate(IV)‐bis{dibromoselenate(II)}, [NnPr4]2[TeBr6(SeBr2)2], the Salt of a Mixed‐valence Bromotellurate(IV)‐Selenate(II) Anion

Dark brown crystals of [NⁿPr₄]₂[TeBr₆(SeBr₂)₂] ( 1 ) were obtained when selenium and bromine (1:1) were allowed to react in acetonitrile solution in the presence of tellurium(IV) bromide and tetrapropylammonium bromide. The salt 1 crystallizes in the monoclinic space group P2₁/n with the cell dimensions a = 14.7870(3) Å, b = 9.5523(3) Å, c = 16.7325(3) Å, β = 110.56(10)° (at 123(2) K). In the solid state the [TeBr₆(SeBr₂)₂]^2– anion contains a nearly regular [TeBr₆] octahedron in which the four equatorial bromo ligands have developed bonds to Se^II atoms of the SeBr₂ molecules. The contacts between the bridging bromo and the Se^II atoms of the SeBr₂ molecules are 3.0000(4) and 3.0561(4) Å, and can be interpreted as bonds of the donor‐acceptor type with the bridging bromo ligands as donors and the SeBr₂ molecules as acceptors. The Te^IV–Br distances are in the range 2.6816(3)–2.7131(3) Å and the Se^II–Br bond lengths in the coordinated SeBr₂ molecules are 2.3548(4) and 2.3725(4) Å.     

Structures of Iodophenyltellurium(II) and Diiododi-(β-naphtyl)tellurium(IV)

The reactions between diphenyl ditelluride, (PhTe)₂, or di(β-naphtyl)ditelluride, (β-naphtylTe)₂, with equivalent amounts of iodine have been reinvestigated and the crystal and molecular structures of iodophenyltellurium(II), (PhTeI)₄, and diiododi-(β-naphtyl)tellurium(IV), (β-naphtyl)₂TeI₂, have been determined. The structure of iodophenyltellurium(II) (space group Cc, a = 13.850(5) Å, b = 13.852(3) Å, c = 16.494(6) Å and β = 101.69(2)°, Z = 4) is built up by four PhTeI units which are linked by weak Te–Te interactions with Te–Te distances between 3.152(5) Å and 3.182(4) Å. The angles between the tellurium atoms are approximately 90° giving an almost perfect square. Long range secondary bonds (Te–I: about 4.2 Å) link the tetrameric units to give an infinite two-dimensional network. Iodo(β-naphtyl)tellurium(II) is less stable than the phenyl derivative. Solutions of this compound decompose under formation of elemental tellurium and (β-naphtyl)₂TeI₂. (β-Naphtyl)₂TeI₂ crystallises in the monoclinic space group C 2/c (a = 21.198(6) Å, b = 5.8921(8) Å, c = 16.651(5) Å, β = 114.77(2)°). The tellurium atom is situated on a two-fold crystallographic axis and Te–I and Te–C bond lengths of 2.899(1) and 2.108(7) Å have been determined.     

Crystal Structure of a Trinuclear Titanium(IV) Complex with (rac)‐3,3′‐Bis(methoxymethyl)‐BINOLate

Reaction of (rac)‐3,3′‐bis(methoxymethyl)‐BINOL [H₂(CH₃OCH₂)₂BINO] with excess Ti(OⁱPr)₄ and one equivalent of H₂O in CH₂Cl₂ affords a trinuclear titanium(IV) complex [{(CH₃OCH₂)₂BINO}Ti₃(μ₃‐O)(OiPr)₆(μ₂‐OiPr)₂]. By dissolving it in dichloromethane and hexane and cooling to 0 °C, plate‐like pale yellow single crystals (monoclinic, P2₁/n, a = 12.605(3), b = 21.994(5), c = 19.090(4) Å, β = 92.764(8)°, V = 5286.2(19) ų, T = 293(2) K) were obtained. Each oxygen atom at 2 or 2′ position of the (CH₃OCH₂)₂BINO ligand bonds to only one titanium atom. There is no interaction between the third Ti atom and the two oxygen atoms of 3,3′‐bis(methoxymethyl)‐BINOLate.     

Bis-(8-oxo quinoline)diorgano tellurium(IV) compounds; structural and spectroscopic studies

Three new compounds of the type R₂Te(OR′)₂ are reported in which R′ bears a potentially co-ordinating group: bis-(8-hydroxo quinoline)dimethyltellurium (I) bis-(8-oxo-2-methyl quinoline)dimethyltellurium (II), and bis-(8-oxo-quinoline) di-(p-tolyl)tellurium (III). The crystal structures of II and III have been determined. The primary geometry around tellurium in both cases can be described as ψ-trigonal bipyramidal but long Te N contacts in the range 2.840(6)–2.899(4) Å which lie well within the van der Waals distance imply extension of the co-ordination sphere. Variable temperature multi-nuclear (¹ H, ¹³C, ¹²⁵Te) studies of the compounds I, II, and III in solution indicate the presence of a single species over the range 216–343 K. The data do not distinguish between the presence of a single 14-Te-6 pertellurane seen in the crystallographic studies, or that of such a species in equilibrium, rapid on the ¹H and ¹²⁵Te timescales, with the 10-Te-4 tellurane.     

The First Orthotelluric Acid Polysilylesters: Synthesis and Crystal Structure of [(Me3SiO)8Te2O2] and [(Me4Si2O2)3Te]

The compounds [(Me₃SiO)₈Te₂O₂] ( 1 ) and [(Me₄Si₂O₂)₃Te] ( 2 ) have been prepared in good yields through Bronsted acid‐base reaction of Te(OH)₆ with Me₃SiNEt₂ and Me₄Si₂(NEt₂)₂, respectively. They have been characterised by multinuclear NMR spectroscopy and single crystal X‐ray diffraction analyses. The formation of dinuclear 1 is the result of fast intermolecular condensation of two partially silylated orthotelluric acid units during the esterification process. Its structure consists of two edge‐fused TeO₆‐octahedra, bearing a four‐membered Te₂O₂ ring as central motif. In contrast, the main structural feature of chiral 2 is a TeO₆ octahedron which is fully silylated by three bidentate 1,1,2,2‐tetramethyldisilanediyl units, resulting in a racemic mixture. The metastability of 2 is remarkable since the Te(+ 6) center usually acts as a strong oxidation reagent toward the Si–Si bond in disilanes. 1 and 2 represent potential starting compounds for molecular Te_xO_y aggregates as hybrid components for new glasses by sol‐gel procedure.     

Syntheses and Properties of Tetrakis(pentafluorophenyl)tellurium,Te(C6F5)4, and Related Compounds — Single Crystal Structures of Tris(pentafluorophenyl)tellurium Bromide,Te(C6F5)3Br,Tris(pentafluorophenyl)tellurium Trifluoromethanesulfonate, [Te(C6F5)3][OSO2CF3], and Bis(pentafluorophenyl)tellurium Oxide,Te(C6F5)2O

Te(C₆F₅)₄ was prepared from the reactions of TeCl₄ or Te(C₆F₅)₂Cl₂ with Grignard reagents or AgC₆F₅ in moderate to good yields. Substitution reactions with Me₃SiX (X = Cl, Br, OSO₂CF₃), with equimolar amounts of Br₂, with AgNO₃ and with H[BF₄] or BF₃·OEt₂ yielded the Te(C₆F₅)₃X derivatives (X = Cl, Br, OSO₂CF₃, NO₃, BF₄). Oxidation reactions of Cd, Hg, and Pd⁰ complexes led to Te(C₆F₅)₂ and the corresponding bis(pentafluorophenyl) derivatives M(C₆F₅)₂ (M = Cd, Hg, Pd) and with InBr to In(C₆F₅)₂Br. From very slow hydrolysis of Te(C₆F₅)₄ the oxide Te(C₆F₅)₂O was prepared. The thermal decomposition, the NMR and mass spectra of the partially new compounds are discussed. The crystal structures of Te(C₆F₅)₃Br (monoclinic, P2₁/a, Z = 4), [Te(C₆F₅)₃][OSO₂CF₃] (monoclinic, P2₁/n, Z = 16) and [Te(C₆F₅)₂O]₂ (triclinic, P1¯, Z = 2) were determined.     

On the Complexes of Bis(trifluoromethyl)ditellurium,Te2(CF3)2, with Halide Ions – A Crystallographic Study of the Pseudo‐trihalides [PNP][(TeCF3)2X] (PNP = Bis(triphenylphosphoranyliden)ammonium; X = Cl,Br, I)

The anions [(TeCF₃)₂X]^? (X = Cl, Br, I) resemble the trihalides [I₂X]^? in the solid state and show similar dynamic behaviour in solution. All three compounds crystallize iso‐structurally in the triclinic space group with Z = 2 and exhibit cell dimensions according to the sizes of the halogen atoms.     

Orthotelluric Acid as Substitute for Crystal‐Water: Syntheses and Crystal Structure of the Co‐crystallate [Te(OH)6 · 2 Adenine · 4 H2O] and the Disodium Ditellurate(VI) Aggregate {[Te2O2(OH)6(ONa)2]2[NaOH · 12.5 H2O]}

Supramolecular aspects on Te(OH)₆ as substitute for crystal‐water in adenine hydrate complexes and the first disodium ditellurate(VI) are reported. The co‐crystallate [Te(OH)₆ · 2 adenine · 4 H₂O] ( 1 ) has been prepared in 41% yield from the 1 : 1 mixing of Te(OH)₆ with the nitrogenous base adenine. The adduct of infinite stacks of adenine molecules, Te(OH)₆ and water not only proves that Te(OH)₆ mimicks the role of water in the related hydrate adenine · 3 H₂O but also shows that the inclusion of Te(OH)₆ raises the number of HO–H and N–HO contacts and therefore increases the distance between the adenine rings to 3.31 Å in 1 in comparison to that in adenine trihydrate (3.22 Å). Additionally, the disodium ditellurate(VI) aggregate {[Te₂(O)₂(OH)₆(ONa)₂]₂ [NaOH · 12.5 H₂O]} ( 2 ) resulted from the reaction of 1 with 2 molar equivalents of aqueous NaOH. Dinuclear 2 represents the first X‐ray diffraction characterized example of a sodium tellurate(VI) constructed from [Te₂O₄(OH)₆]^2– dianions.     

Synthesis and Crystal Structure of Bis(methyltriphenylphosphonium) Hexabromotellurate(IV)‐bis{dibromoselenate(II)}, [PMePh3]2[TeBr6(SeBr2)2], the Salt of a Mixed‐valence Bromotellurate(IV)‐Selenate(II) Anion

Brown crystals of [PMePh₃]₂[TeBr₆(SeBr₂)₂] ( 1 ) were obtained when selenium and bromine (1:1) react in acetonitrile solution in the presence of tellurium(IV) bromide and methyltriphenylphosphonium bromide. The salt 1 crystallizes in the triclinic space group P1¯ with the cell dimensions a = 10.3630(14)Å, b = 11.5140(12)Å, c = 11.7605(17)Å, α = 108.643(9)°, β = 106.171(10)° and γ = 99.077(9)° (296 K). In the solid state the [TeBr₆(SeBr₂)₂]^2— anion contains a nearly regular [TeBr₆] octahedron where the four equatorial bromo ligands each have developed a bond to the Se^II atom of a SeBr₂ molecule. The contacts between the bridging bromo and the Se^II atoms of the SeBr₂ molecules are observed in the range 3.11—3.21Å, and can be interpreted as bonds of the donor‐acceptor type with the bridging bromo ligands as donors and the SeBr₂ molecules as acceptors. The Te^IV—Br distances are in the range 2.67—2.72Å, and the Se^II—Br bond lengths in coordinated SeBr₂ molecules in the range 2.33—2.34Å.     

Molecular Structures of Dibromo[(E)2‐bromo‐2‐phenylvinyl]‐(phenyl) tellurium (IV) and Dibromo [(Z)‐2‐bromo‐2‐phenyl‐vinyl] (p‐tulyl) tellurium (IV) hydrate methanolate

The structures of title compounds, [TeBr₂(C₈H₆Br)(C₆H₅)] (I) and [TeBr₂(C₈H₆Br)(C₇H₉)](H₂O)(CT₃OH) (II), have been determined by X‐ray diffraction. The structures confirm that E‐ or Z‐type configuration of vinylic telluride depends on the polarity of solvent employed. In either structure, Te atom is in a trigonal dipyramide configuration with the lone pair of electrons in the equatorial position.     

Synthesis and Crystal Structure of Bis(methyltriethylammonium) Hexabromotellurate(IV)‐tris{dibromodiselenate(I)}, [NMeEt3]2n[TeBr6(Se2Br2)3]n,Containing a Chain‐Polymeric Mixed‐valence Bromotellurate(IV)‐Selenate(I) Anion

Red crystals of [NMeEt₃]_2n[TeBr₆(Se₂Br₂)₃]n ( 1 ) were isolated when selenium and bromine (1:1) were allowed to react in acetonitrile solution in the presence of tellurium(IV) bromide and methyltriethylammonium bromide (1:2). The salt 1 crystallizes in the monoclinic space group C2/c with the cell dimensions a = 27.676(6) Å, b = 9.665(2) Å, c = 18.796(4) Å and ß = 124.96(3)° (120 K). The [TeBr₆(Se₂Br₂)₃]^2— anions contain nearly regular octahedral [TeBr₆]^2— ions which are incorporated into a polymeric chain by bonding contacts between 3 facial bromo ligands and 3 Se₂Br₂ molecules, one of which is situated on the twofold symmetry axis. The distances between the μBr ligands and the Se^I atoms of the Se₂Br₂ molecules are observed in the range 3.308(2) — 3.408(2) Å and can tentatively be interpreted as donor‐acceptor bonds with μBr as donors and Se₂Br₂ as acceptors. The Te^IV—Br distances are in the range 2.669(1) — 2.687(1) Å. The bond lengths in the connecting Se₂Br₂ molecules are: Se^I—Se^I = 2.267(2) and 2.281(2) Å, Se^I—Br = 2.340(1), 2.353(1) and 2.337(1) Å.     

Synthesis,Structure and Selective Chlorination of Bis(N‐borane‐dimethylaminopropyl)telluride

The reaction of Te powder, NaBH₄ and Me₂N(CH₂)₃Cl·HCl provided the title compound [H₃BNMe₂(CH₂)₃]₂Te ( 1 ), whose selective chlorination with SO₂Cl₂ lead to the formation of [ClH₂BNMe₂(CH₂)₃]₂TeCl₂ ( 2 ) and [Cl₃BNMe₂(CH₂)₃]₂TeCl₂ ( 3 ), respectively. Compounds 1 – 3 were characterized by multinuclear NMR spectroscopy and single crystal X‐ray diffraction.     

Synthesis and Crystal Structure of Manganese‐tris(1,2‐ethanediamine)tetratelluride [Mn(en)3]Te4 Exhibiting Intermolecular Interactions between the Tetratelluride Anions

Air‐sensitive black crystals of the new compound [Mn(en)₃]Te₄ were synthesized by reacting MnCl₂ · 4 H₂O, K₂Te₃ and elemental Te in 1,2‐ethanediamine (en) under solvothermal conditions at 433 K. The compound crystallizes in the monoclinic space group P2₁/n with lattice parameters a = 839.51(7) pm, b = 1551.3(1) pm, c = 1432.6(1) pm, and β = 90.28(2)°. Isolated [Mn(en)₃]²⁺ cations and Te₄^2– anions are arranged in an alternating fashion parallel to the crystallographic b‐axis. One terminal Te atom of the Te₄^2– anions exhibits a short intermolecular contact to a neighboured anion thus forming Te₈^4– anions. A slightly longer interionic Te…Te separation is observed between two of the inner Te atoms of neighboured Te₈^4– anions. Taking these longer separations into account infinite Te‐chains are formed running parallel to [001]. The intermolecular Te…Te interactions affect the Te–Te bond lengths within the Te₄^2– anion leading to a lengthening of the average Te–Te distance. Short N–H…Te distances indicate hydrogen bonding between the cations and anions. DTA‐TG measurements show that at 441 K the material decomposes in one step. The resulting crystalline material consists of MnTe₂ and Te.     

New Mixed Ligand Organotellurium(IV) Compounds Containing Dithiocarbamates and the More Flexible Imidotetraphenyldithiodiphosphinates. The Crystal Structures of C8H8Te(S2CNEt2)[(SPPh2)2N] · H2O,C8H8Te(S2CNC5H10)[(SPPh2)2N], and C8H8Te(S2CNC4H8S)[(SPPh2)2N]

The synthesis of the following mixed ligand organotellurium(IV) compounds C₈H₈Te(S₂CNEt₂)[(SPPh₂)₂N] · H₂O ( 1 ), C₈H₈Te(S₂CNC₅H₁₀)[(SPPh₂)₂N] ( 2 ), C₈H₈Te(S₂CNC₄H₈O)[(SPPh₂)₂N] ( 3 ) and C₈H₈Te(S₂CNC₄H₈S)[(SPPh₂)₂N] ( 4 ) was achieved. They were characterized by IR, ¹H, ¹³C, ³¹P and ¹²⁵Te NMR, mass spectroscopy, and elemental analyses. The X‐ray crystal structures of 1 , 2 and 4 were determined. The both types of ligands display an asymmetrical chelating coordination mode on interaction with the tellurium atom. When these aniso‐bonded donor atoms are included in the coordination sphere, the tellurium atom exhibit an effective co‐ordination number of seven. The arrangement may be described as 1 : 2 : 2 : 2 coordination with a presumably stereoactive lone‐pair of electrons.     

Synthesis and Crystal Structures of Neutral Complexes of Tellurium(IV) – [PhTeX3L](X = Br,I; L = ethylenethiourea)

A three‐step one‐pot synthetic procedure to synthesize the neutral tellurium(IV) coordination compounds PhTeX₃L (X = Br, I and L = ethylenethiourea) has been developed and is described in this article. Oxidative halogenation of PhTeTePh in methanol generates the tellurium(II) derivative, PhTeX, which is subsequently complexed with ethylenethiourea, and, finally, further oxidative addition of additional halogen affords the corresponding tellurium(IV) compound PhTeX₃L in good yields. The final product was obtained by the slow evaporation of the reaction mixture as black crystals. The X‐ray structural analyses of the compounds show Te···X and X···X secondary interactions in the solid state and suggest a weak dependence of the formation of supramolecular assemblies on the nature of the halogen bonded to the tellurium atom.     

Synthesis and Crystal Structure of Cs(VO2)3(TeO3)2, a New Layered Cesium Vanadium(V) Tellurite

Synthetic Cs(VO₂)₃(TeO₃)₂ is built up from infinite sheets of distorted octahedral V^VO₆ groups, sharing vertices. These octahedral layers are “capped” by Te atoms (as parts of pyramidal [Te^IVO₃]^2– groups) on both faces of each V/O sheet, with inter‐layer, 12‐coordinate, Cs⁺ cations providing charge compensation. Cs(VO₂)₃(TeO₃)₂ is isostructural with M(VO₂)₃(SeO₃)₂ (M = NH₄, K). Crystal data: Cs(VO₂)₃(TeO₃)₂, M_r = 732.93, hexagonal, space group P6₃ (No. 173), a = 7.2351(9) Å, c = 11.584(2) Å, V = 525.1(2) ų, Z = 2, R(F) = 0.030, wR(F ²) = 0.063.     

Darstellung und Kristallstruktur eines Ditelluridovanadium(IV)‐Komplexes: [(μ‐η1‐Te2)(μ‐NtBu)2V2Cp2]

Synthesis and Crystal Structure of a Ditelluridovanadium(IV) Complex: [(μ‐η¹‐Te₂)(μ‐N^tBu)₂V₂Cp₂] [(μ‐η¹‐Te₂)(μ‐N^tBu)₂V₂Cp₂] ( 2 ) is formed from [^tBuN = VCp(PMe₃)₂] ( 1 ) upon reaction with elemental tellurium. 1 and 2 are characterized by spectroscopic methods (MS; ¹H, ¹³C, ⁵¹V NMR), in addition 2 by single crystal X‐ray diffraction. The crystal structure indicates a folded cyclodivanadazen ring bridged by a bidentated ditellurido ligand, the first example of this structure type.