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.     

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.     

Synthesis and Crystal Structure of Bis(tetraphenylphosphonium) Hexabromo‐diselenate(II)‐bis{dibromodiselenate(I)}, [PPh4]2[Se2Br6(Se2Br2)2], the Salt of a Mixed‐valence Bromoselenate(II,I) Anion

The Red crystals of [PPh₄]₂[Se₂Br₆(Se₂Br₂)₂] ( 1 ) were obtained when selenium and bromine reacted in the solution of acetonitrile in the presence of tetraphenylphosphonium bromide. The crystal structure of 1 has been determined by X‐ray diffraction and refined to R = 0.0201 for 4024 reflections. The crystals are triclinic, space group with Z = 2 and a = 11.2757(4) Å, b = 12.3347(5) Å, c = 12.4948(5) Å, α = 113.152(4)°, β = 114.745(4)°, γ = 91.208(3)° (120(2) K). In the solid state the anion of 1 is built up of the Se₂Br₆ core and two Se₂Br₂ molecules each of which is linked to one of the trans‐positioned terminal Br_t atoms of the Se₂Br₆ core. The central Se₂Br₆ part consists of a nearly planar arrangement of two planar SeBr₄ units sharing a common edge through two μ₂‐bridging Br atoms. The contact between the Br_t and the Se^I atom of the Se₂Br₂ molecule is 3.0872(5) Å and can be interpreted as a bond of the donor‐acceptor type with the Br_t as donor and the Se₂Br₂ molecule as acceptor. The terminal Se^II–Br and μ₂Br–Se^II bond lengths are 2.3654(4), 2.6699(5) Å and 2.5482(5), 3.0265(5) Å, respectively. The bond lengths in the coordinated Se₂Br₂ molecule are: Se^I–Se^I = 2.2686(5) Å, Se^I–Br = 2.3779(5) and 2.3810(5) Å.     

Synthesis and Crystal Structure of Bis(tetraethylammonium) Octabromo‐triselenate(II)‐{dibromodiselenate(I)}, [NEt4]2[Se3Br8(Se2Br2)], the Salt of a Mixed‐valence Bromoselenate(II,I) Anion

The brown crystals of [NEt₄]₂[Se₃Br₈(Se₂Br₂)] ( 1 ) were obtained when selenium and bromine reacted in the solution of acetonitrile in the presence of tetraethylammonium bromide. The crystal structure of 1 has been determined by the X‐ray methods and refined to R = 0.0308 for 10433 reflections. The crystals are monoclinic, space group P2₁ with Z = 2 and a = 12.0393(3) Å, b = 11.8746(3) Å, c = 13.1946(3) Å, β = 96.561(1)° (123 K). In the solid state structure the anion of 1 is built up of Se₃Br₈ unit which consists of a triangular arrangement of three planar SeBr₄ units sharing a common edge through two μ₃‐bridging Br atoms, and one Se₂Br₂ molecule which is linked to one of μ₃‐bridging Br atoms. The three Se^II atoms form a triangle which is almost perpendicular to the planes given by three SeBr₄ moieties. The contact between the μ₃Br and the Se^I atom of the Se₂Br₂ molecule is 3.1711(8) Å and can be interpreted as a bond of the donor‐acceptor type with the μ₃Br as donor and the Se₂Br₂ molecule as acceptor. The terminal Se^II‐Br and μ₃Br‐Se^II bond lengths are in the ranges 2.3537(7)–2.4737(7) Å and 2.7628(7)–3.1701(7) Å, respectively. The bond lengths in coordinated Se₂Br₂ molecule are: Se^I‐Se^I = 2.2636(9) Å, Se^I‐Br = 2.3387(11) and 2.3936(8) Å.     

Neue Halogenochalkogen(IV)‐Säuren: [H3O(Benzo‐18‐Krone‐6)]2[Te2Br10] und [H5O2(Dibenzo‐24‐Krone‐8)]2[Te2Br10]

Novel Halogenochalcogeno(IV) Acids: [H₃O(Benzo‐18‐Crown‐6)]₂[Te₂Br₁₀] and [H₅O₂(Dibenzo‐24‐Crown‐8)]₂[Te₂Br₁₀] Systematic studies on halogenochalcogeno(IV) acids containing tellurium and bromine led to the new crystalline phases [H₃O(Benzo‐18‐Crown‐6)]₂[Te₂Br₁₀] ( 1 ) and [H₅O₂(Dibenzo‐24‐Crown‐8)]₂[Te₂Br₁₀] ( 2 ). The [Te₂Br₁₀]^2‐ anions consists of two edge‐sharing distorted TeBr₆ octahedra, the oxonium cations are stabilized by crownether. ( 1 ) crystallizes in the monoclinic space group P2₁/n with a = 14.520(5) Å, b = 22.259(6) Å, c = 16.053(5) Å, β = 97.76(3)° and Z = 4, whereas ( 2 ) crystallizes in the triclinic space group with a = 11.005(4) Å, b = 12.103(5) Å, c = 14.951(6) Å, α = 71.61(3)°, β = 69.17(3)°, γ = 68.40(3)° and Z = 1.     

Direct Syntheses of Bis(tetraphenylphosphonium) and Bis(ethyltriphenylphosphonium) Hexabromo‐diselenates(II), [PPh4]2[Se2Br6] and [PEtPh3]2[Se2Br6]. The Crystal Structure of [PEtPh3]2[Se2Br6]

Brown crystals of [PPh₄]₂[Se₂Br₆] ( 1 ) and [PEtPh₃]₂[Se₂Br₆] ( 2 ) were obtained when selenium and bromine reacted in acetonitrile solution in the presence of tetraphenylphosphonium bromide and ethyltriphenylphosphonium bromide, respectively. The crystal structure of 2 has been determined by X‐ray methods and refined to R = 0.0420 for 4161 reflections. The crystals are monoclinic, space group P2₁/n with Z = 2 and a = 13.055(3) Å, b = 12.628(3) Å, c = 13.530(3) Å, β = 92.40(3)° (293(2) K). In the solid state structure of 2 the dinuclear hexabromo‐diselenate(II) anion is centrosymmetric and consists of two distorted almost square‐planar SeBr₄ units sharing a common edge through two bridging Br atoms. The terminal Se^II–Br bond distances are found to be 2.419(1) and 2.445(1) Å, the bridging μBr–Se^II bond distances 2.901(1) and 2.802(1) Å.     

Struktur von Bis[salicylaldehyd-2-hydroxyanilato(2—)]vanadium(IV)

Molecular Structure of Bis[salicylaldehyde-2-hydroxyanilato(2—)]vanadium(IV) By the reaction of tris(acetylacetonato)vanadium(III) with salicylaldehyde-2-hydroxyanil the non-oxo vanadium(IV) complex of this ligand was prepared. Bis[salicylaldehyde-2-hydroxyanilato(2—)]vanadium(IV) has a distorted octahedral structure. Crystallographic data see “Inhaltsübersicht”.     

Synthesis and Crystal Structure of Tetrakis(tetramethylammonium) Bis[decabromotetraselenate(II)]‐bis[dibromodiselenate(I)], [(CH3)4N]4[(Se4Br10)2(Se2Br2)2], the Salt of a Mixed‐Valence Bromoselenate(II/I) Anion

Brown crystals of [NMe₄]₄[(Se₄Br₁₀)₂(Se₂Br₂)₂] ( 1 ) were obtained from the reaction of selenium and bromine in acetonitrile in the presence of tetramethylammonium bromide. The crystal structure of 1 was determined by X‐ray diffraction and refined to R = 0.0297 for 8401 reflections. The crystals are monoclinic, space group P2₁/c with Z = 4 and a = 12.646(3) Å, b = 16.499(3) Å, c = 16.844(3) Å, β = 101.70(3)° (123 K). In the solid‐state structure, the anion of 1 is built up of two [Se₄Br₁₀]^2– ions. Each shows a triangular arrangement of three planar SeBr₄ units sharing a common edge through two μ₃‐bridging bromine atoms, and one SeBr₂ molecule, which is linked to the Se^II atoms of two SeBr₄ units; between the Se₄Br₁₀^2– ions a dimerized Se₂Br₂ molecule (Se₄Br₄) is situated and one Se^I atom of each Se₂Br₂ molecule has two weak contacts [3.3514(14) Å and 3.3952(11) Å] to two bromine atoms of one SeBr₄ unit. Four Se^I atoms of a dimerized Se₂Br₂ molecule are in a almost regular planar tetraangular arrangement. Contacts between the Se^II atom of the SeBr₂ molecule and the Se^II atoms of two SeBr₄ units are 3.035(1) Å and 3.115(1) Å, and can be interpreted as donor‐acceptor type bonds with the Se^II atoms of SeBr₄ units as donors and the SeBr₂ molecule as acceptor. The terminal Se^II–Br and μ₃‐Br–Se^II bond lengths are in the ranges 2.3376(10) to 2.4384(8) Å and 2.8036(9) to 3.3183(13) Å, respectively. The bond lengths in the dimerized Se₂Br₂ molecule are: Se^I–Se^I = 2.2945(8) Å and 3.1398(12), Se^I–Br = 2.3659(11) and 2.3689(10) Å.     

Trifluoromethylselenate(0), [SeCF3]—, and Trifluoromethyltellurate(0), [TeCF3]— — Crystalline Products of the Reduction of the Bis(trifluoromethyl)dichalkogen Compounds,E2(CF3)2 (E = Se,Te), with Tetrakis(dimethylamino)ethene (TDAE)

[Bis(dimethylamino)ethanediylidene]bis(dimethylammonium) bis(trifluoromethylchalcogenates(0)), (TDAE)[ECF₃]₂ (E = Se, Te), are quantitatively formed from the reductions of E₂(CF₃)₂ with tetrakis(dimethylamino)ethene, TDAE. Both compounds are bright yellow to orange solids which crystallize isostructurally with the corresponding sulfur derivative in the orthorhombic space group Pbca (No. 61). (TDAE)[SeCF₃]₂ has alternatively been prepared by cation exchange from [NMe₄]SeCF₃ and (TDAE)Br₂.     

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.     

Das erste Alkalimetall‐Lanthanoid(III)‐Iodid‐Oxotellurat(IV): Na2Lu3I3[TeO3]4

Colorless platelets of Na₂Lu₃I₃[TeO₃]₄ were obtained within five days at 775 °C by the reaction of Lu₂O₃ and TeO₂ in a 3:8 molar ratio with NaI added in excess as both fluxing agent and reactant in evacuated silica ampoules. It crystallizes in the monoclinic space group P2/c with the lattice parameters a = 921.69(5), b = 552.71(3), c = 1664.37(9) pm, β = 90.218(4)° and Z = 2. The crystal structure of Na₂Lu₃I₃[TeO₃]₄ exhibits two crystallographically different Lu³⁺ cations, both coordinated by eight O^2– anions as square antiprisms. These polyhedra are interconnected through four common edges to build up {}^2_∞ {[LuO{}^e_8/2 ]^5–} layers (e = edge‐linking) parallel to (100). Furthermore, the crystal structure includes a crystallographically unique Na⁺ cation surrounded by four O^2– and four I^– anions also in the shape of a square antiprism. These polyhedra connect via common (I2)^–···(I2)^– edges in generating {}^1_∞ {[Na₂O₈I{}^e_4 ]^18–} double‐strands that are further linked by (I1)^– vertices to result in the formation of {}^2_∞ {[Na₂O₈I₃{}^e,v_3 ]^17–} layers (v = vertex‐linking) spreading out parallel to (100) as well. Thus, the crystal structure contains two crystallographically distinct I^– anions, of which (I1)^– is coordinated nearly linear (? (Na–I1–Na) = 179.6°) by two Na⁺ cations, whereas (I2)^– has contact to three of them displaying a distance of 114 pm from the triangular (Na⁺)₃ plane. The crystal structure of Na₂Lu₃I₃[TeO₃]₄ is completed by two crystallographically independent Te⁴⁺ cations that show stereochemically active non‐bonding electron pairs (“lone pairs”) and are located above and below the {}^2_∞ {[LuO{}^e_8/2 ]^5–} layers forming isolated ψ¹‐tetrahedral [TeO₃]^2– anions (d(Te–O) = 188–190 pm) with all oxygen atoms.     

Synthese und Kristallstruktur des Holmium(III)‐chlorid‐oxotellurats(IV) HoClTeO3

Synthesis and Crystal Structure of the Holmium(III) Chloride Oxotellurate(IV) HoClTeO₃ Orange coloured, rod—shaped single crystals of the holmium( III) chloride oxotellurate(IV) HoClTeO₃ (orthorhombic, Pnma; a = 730.25(5), b = 696.54(5), c = 905.18(7) pm; Z = 4) are obtained during attempts to synthesize holmium(III) oxochlorotellurates(IV) by reaction of holmium oxychloride (HoOCl) and tellurium dioxide (TeO₂; 1:1—2molar ratio, 800 °C, 40 d) in evacuated silica tubes. The crystal structure contains sevenfold coordinated Ho ³⁺ cations surrounded by five oxide and two chloride anions forming a pentagonal bipyramid. Interconnection of the [Ho(O1)(O2)₄Cl₂] polyhedra occurs via two edges made of four equatorial oxygen atoms (O2) under formation of {[Ho(O1)(O2)_4/2Cl_2/1]^5‐} chains running parallel [010]. These arrange as hexagonal closest packing of rods and are linked to each other by Cl^‐ anions to a three—dimensional {[Ho(O1)_1/1(O2)_4/2Cl_2/2]^4‐} network. All Te⁴⁺ cations are embedded therein and exhibit ψ¹—tetrahedral coordination figures as discrete anionic [Te(O1)(O2)₂]^2‐ pyramids due to the stereochemical activity of the non—binding electron pairs („lone pairs”︁). They stabilize the {[HoO₃Cl]^4‐} network via covalent bonds to one axial (O1) and two equatorial oxygen atoms (O2) of each [HoO₅Cl₂] polyhedron.     

π‐Complexes of Copper(I) Ionic Salts: Synthesis and Crystal Structure of (4‐Allylthiosemicarbazide)(sulfamato)copper(I) and Bis(4‐allylthiosemicarbazide)(sulfato‐O)dicopper(I)

Single crystals of [Cu(ATSC)]NH₂SO₃ ( 1 ) (ATSC –4‐allylthiosemicarbazide) were obtained by electrochemical synthesis using alternating current. Compound ( 1 ) crystallizes in P2₁2₁2₁ sp. gr., a = 6.8284(2), b = 9.3054(3), c = 16.1576(11) Å, Z = 4. ATSC moiety acts as tetradentate ligand, chelating two symmetrically related copper atoms. The Cu atom possesses trigonal pyramidal coordination, formed by two sulphur atoms (one of them at the apical position), nitrogen atom and C=C bond. Sulfamate anion is associated via hydrogen bonds. By slow hydrolysis of 1 crystals of [Cu₂(ATSC)₂]SO₄ ( 2 ) were obtained: P 1 sp. gr., a = 9.526(2), b = 12.687(2), c = 14.7340(10) Å, α = 95.119(10), β = 89.903(12), γ = 109.113(14)°, Z = 4. The asymmetric unit of 2 contains two formula units, which are related by pseudosymmetry via a glide plane a. One half of four ATSC molecules act as in 1 , the rest as tridentate ligands, which coordinate the two copper atoms in apical positions with sulfate anions. This Cu–S coordination was to date unknown. The structure of the ATSC ligands contributes to the unexpected competitiveness of C=bond in the coordination sphere of Cu^I inspite of strong donor atoms.     

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.     

Crystallographic report: Bis(3‐methyl‐2‐cyclopenten‐1‐one)dichloro‐oxovanadium(IV)

The crystal structure of the oxovanadium(IV) complex (CH₃C₅H₅O)₂VOCl₂ was determined. The molecule has trigonal bipyramidal geometry, with oxygen atoms of cyclopentenones in axial positions and oxygen and two chlorine atoms in equatorial positions. Copyright © 2005 John Wiley & Sons, Ltd.     

Azidokomplexe von Vanadium(IV) und Vanadium(V): (Ph4P)2[VOCl2(μ‐N3)]2 und (Ph4P)2[VOCl(μ‐N3)(N3)2]2

Azido Complexes of Vanadium(IV) and Vanadium(V): (Ph₄P)₂[VOCl₂(μ‐N₃)]₂ and (Ph₄P)₂[VOCl(μ‐N₃)(N₃)₂]₂ (Ph₄P)₂[VOCl₂(μ‐N₃)]₂ ( 1 ) was prepared by reaction of (Ph₄P)[VO₂Cl₂] with trimethylsilylazide in the molar ratio 1:2 in dichloromethane solution to give dark green, moisture sensitive, non‐explosive single crystals. The reaction is accompanied by the formation of the dark blue side‐product (Ph₄P)₂[VOCl(μ‐N₃)(N₃)₂]₂ ( 2a ), which can be obtained as the main product by application of a large excess of Me₃SiN₃. Dark blue needles of 2a crystallize spontaneously from the CH₂Cl₂ solution within one hour at 4 °C. After standing at 4 °C under its mother liquid within 24 hours a first‐order phase transition of 2a occurs forming dark blue prismatic single crystals of 2b . According to single crystal X‐ray structure determinations, 2a and 2b crystallize in the same type of space group , however, with different lattice dimensions. The vanadium(IV) complex 1 is characterized by X‐ray structure determination and by vibrational spectroscopy (IR, Raman) as well as by EPR spectroscopy, whereas 2b is characterized by IR spectroscopy. 1 : Space group P2₁/n, Z = 2, a = 1009.5(1), b = 1226.6(2), c = 1943.0(2) pm, β = 98.42(1)°, R₁ = 0.0672. The complex anion forms centrosymmetric units with V₂N₂‐four‐membered rings with a V···V distance of 335.6(1) pm and coordination number five on the vanadium(IV) atoms. 2a : Space group , Z = 1, a = 1089.0(2), b = 1097.1(2), c = 1310.1(2) pm, α = 92.99(1)°, β = 106.12(2)°, γ = 117.05(2)°, V = 1309.8(4) ų, d_calc. = 1.440 g·cm^?3, R₁ = 0.0384. The complex anion forms centrosymmetric units of symmetry C_i with V₂N₂ four‐membered rings and VN bond lengths of 200.4(3) and 234.4(2) pm, respectively. The non‐bonding V···V distance amounts to 356.2(1) pm. 2b : Space group , Z = 1, a = 1037.3(2), b = 1157.6(2), c = 1177.2(2) pm, α = 98.48(2)°, ° = 103.82(2)°, γ = 106.33(2)°, V = 1281.8(4) ų, d_calc. = 1.471 g·cm^?3, R₁ = 0.0724. The structure of the complex anion is similar to the anion of 2a with VN bond lengths of the four‐membered V₂N₂ ring of 203.3(4) and 235.2(4) pm, respectively, and a non‐bonding V···V distance of 357.5(1) pm.     

[H3O · (Dibenzo-18-crown-6)][Te2Br9] and [H5O2][Te2Cl9] · 2 C4H8O2: Two New Oxonium Halotellurates(IV) Containing a Novel Type of [Te2X9]– Anions

Red crystals of [H₃O · (dibenzo-18-crown-6)][Te₂Br₉] ( 1 ) were isolated from a solution of TeBr₄ and dibenzo-18-crown-6 in CH₃CN containing a small amount of hydrobromic acid. The compound crystallizes in the triclinic space group P 1 with the cell dimensions a = 9.010(2), b = 13.403(3), c = 14.606(4) Å, α = 98.94(2)°, β = 100.40(2)°, and γ = 91.40(2)° (150 K). From a solution of TeCl₄ in 1,4-dioxane containing hydrochloric acid [H₅O₂][Te₂Cl₉] · 2 C₄H₈O₂ ( 2 ) precipitates as colorless crystals in the orthorhombic space group Pnma with the cell dimensions a = 17.023(4), b = 13.389(4), and c = 10.900(3) Å (150 K). In both structures the [Te₂X₉]^– anion (X = Cl, Br) consists of one TeX₆ octahedron and one TeX₅ square pyramidal unit connected by a common edge. In compound 1 the coordination sphere of the square pyramidal fragment is completed by a very weakly η⁶ bound benzo group of the cationic unit. In compound 2 an oxygen atom of the oxonium ion weakly interacts with the fivefold coordinated tellurium atom. The cationic units are a crown ether oxonium complex in 1 and a supramolecular 1,4-dioxane-oxonium network in 2 .     

Synthesis and Structure of the Bicyclic [Sn4Se11]6– Anion in Na6Sn4Se11 · 22 H2O

Na₆Sn₄Se₁₁ · 22 H₂O can be crystallised at –8 °C as yellow‐orange needles from the 1 : 2 H₂O/CH₃OH mother liquor of a superheated reaction mixture of NaOH(s), Sn and Se. The bicyclic [Sn₄Se₁₁]^6– anion exhibits crystallographic C₂ symmetry and is composed of corner‐bridged SnSe₄ tetrahedra. Two opposite tin atoms of an Sn₄Se₄ 8‐membered ring are linked by a common Se atom, thereby affording two 6‐membered boat‐shaped Sn₃Se₃ rings with a shared Sn–Se–Sn bridging unit. [Sn₄Se₁₁]^6– thus represents the immediate precursor of the well‐known adamantane‐like [Sn₄Se₁₀]^4– anion.     

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.     

Molybdän‐ und Wolfram‐Komplexe mit MNS‐Sequenzen. Die Kristallstrukturen von [MoCl3(N3S2)(1,4‐Dioxan)2] und [Mo2Cl2(μ‐NSN)2(μ‐O)(NCMe3)(OCMe3)2]2

Molybdenum and Tungsten Complexes with MNS Sequences. Crystal Structures of [MoCl₃(N₃S₂)(1,4‐dioxane)₂] and [Mo₂Cl₂(μ‐NSN)₂(μ‐O)(NCMe₃)(OCMe₃)₂]₂ The cyclo‐thiazeno complexes [Cl₃MNSNSN]₂ of molybdenum and tungsten react with 1,4‐dioxane in dichloromethane suspension to give the binuclear donor‐acceptor complexes [μ‐(1,4‐dioxane){MCl₃(N₃S₂)}₂] which are characterized by IR spectroscopy. With excess 1,4‐dioxane the molybdenum compound forms the complex [MoCl₃(N₃S₂)(1,4‐dioxane)₂] in which, according to the crystal structure determination, one of the dioxane molecules coordinates at the molybdenum atom, the other one at one of the sulfur atoms of the cyclo‐thiazeno ring. The μ‐(NSN^2–) complex [Mo₂Cl₂(μ‐NSN)₂(μ‐O)(NCMe₃)(OCMe₃)₂]₂ has been obtained by the reaction of [MoN(OCMe₃)₃] with trithiazyle chloride in carbontetrachloride solution. According to the crystal structure determination this compound forms centrosymmetric dimeric molecules via two of the nitrogen atoms of two of the μ‐(NSN) groups to give a Mo₂N₂ fourmembered ring. [MoCl₃(N₃S₂)(1,4‐dioxane)₂]: Space group P2₁/c, Z = 4, lattice dimensions at –70 °C: a = 1522.9(2); b = 990.3(1); c = 1161.7(1) pm; β = 106.31(1)°, R₁ = 0.0317. [Mo₂Cl₂(μ‐NSN)₂(μ‐O)(NCMe₃)(OCMe₃)₂]₂ · 4 CCl₄: Space group P2₁/c, Z = 2, lattice dimensions at –83 °C: a = 1216.7(1); b = 2193.1(2); c = 1321.8(1) pm; β = 98.23(1)°; R₁ = 0.0507.