Die Kristallstruktur von (PPh4)2[Mo2(O2C?Ph)4Br2] · 2 CH2Br2

Crystal Structure of (PPh₄)₂[Mo₂(O₂C? Ph)₄Br₂] · 2 CH₂Br₂ The title compound, prepared by the reaction of Mo₂(O₂C? Ph)₄ with PPh₄Br and PPh₄N₃, respectively, under the assistance of CH₂Br₂, was characterized by an X-ray structure determination. Space group P2₁/n, Z = 2, R = 0.074 (5261 independent observed reflexions). The lattice dimensions are at ?70°C: a = 1562.9, b = 1406.2, c = 1662.1 pm, β = 94.11°. the compound consists of PPh₄^⊕ ions, CH₂Br₂ molecules, and centrosymmetric anions [Mo₂(O₂C? Ph)₄Br₂]^2?. The axis Br? Mo?Mo–Br is nearly linear (bond angle 175.6°) with bond lengths MoMo = 212.3 pm and Mo? Br = 303 pm, corresponding with a weak electrostatic Mo? Br bond. In the FIR spectrum the Mobr stretching vibration is found at 85 cm^?1, which corresponds with the low value of the force constant of 0.24 N · cm^?1.     

Synthese und Struktur von (PPh4)3[Re2NCl10]

Synthesis and Crystal Structure of (PPh₄)₃[Re₂NCl₁₀] The rhenium(V) nitrido complex (PPh₄)₃[Re₂NCl₁₀] ( 1 ) is obtained from the reaction of (PPh₄)[ReNCl₄] with 1, 3‐dioxan‐(2‐ylmethyl)diphenyl phosphine in CH₂Cl₂/CH₃CN in form of orange red crystals with the composition 1 ·2CH₂Cl₂ crystallizing in the triclinic space group P1¯ with a = 1210.7(2), b = 1232.5(1), c = 2756.3(5) pm, α = 99.68(1)°, β = 100.24(1)°, γ = 98.59(1)° and Z = 2. The crystal structure contains two symmetry independent, centrosymmetrical complex anions [Re₂NCl₁₀]^3‐ with a symmetrical nitrido bridge Re=N=Re and distances Re(1) ‐ N(1) = 181.34(5) and Re(2) ‐ N(2) = 181.51(4) pm.     

Thiokomplexe des Molybdäns Kristallstruktur eines Mischkristalls (PPh3Me)2[Mo2Br6(NO)4]/(PPh3Me)2[Mo2Br6S2(NO)2]

Thiocomplexes of Molybdenum. Crystal Structure of a Mixed Single Crystal (PPh₃Me)₂[Mo₂Br₆(NO)₄]/(PPh₃Me)₂[Mo₂Br₆S₂(NO)₂] The reactions of (PPh₄)₂MoS₄ with MoBr₄ and MoBr₂(NO)₂ resp. lead to the binuclear complexes (PPh₄)₂[S₂MoS₂MoBr₃(SMe₂)] and (PPh₄)[S₂MoS₂MoBr₂(NO)₂], in which the molybdenum atoms are linked by sulfido bridges. The preparation of (PPh₃Me)₂S₆ and (AsPh₄)₂S₇ from Na₂S₄ and PPh₃MeBr, and AsPh₄Cl, respectively, in ethanol solution is described. Disulfido briges are a feature of (AsPh₄)₂[Mo₂Br₆(S₂)₂(SMe₂)₂], which is obtained from MoBr₄(SMe₂)₂ and (AsPh₄)₂S₇. Mixed single crystals containing 2/3 (PPh₃Me)₂[Mo₂Br₆(NO)₄] and 1/3 (PPh₃Me)₂[Mo₂Br₆S₂(NO)₂] are formed in the reaction of MoBr₂(NO)₂ with (PPh₃Me)₂S₆, as shown by X-ray single crystal structure determination. The compound crystallizes monoclinic in the space group C2/c (Internat. Tab. Nr. 15) with four formula units per unit cell (2351 independent observed reflexions, R_w = 0.037). The cell parameters are a = 1603 pm, b = 1549 pm, c = 1863 pm; β = 92.2°. The complexes consist of PPh₃Me^⊕ cations and the dimeric anions [Mo₂Br₆(NO)₄]^2? and [Mo₂Br₆S₂(NO)₂]^2? which occur in the ratio 2:1. In these the molybdenum atoms are connected via MoBr₂Mo bridges of slightly different lengths (Mo? Br 265 pm and 267 pm) forming a controsymmetric double octahedron. All molybdenum atoms have two terminal bromo ligands with Mo? Br bond lengths of 258 pm and 260 pm; in the [Mo₂Br₆(NO)₄]^2? ion each molybdenum has two covalently bonded nitrosyl groups on cis-position with Mo? N bond lengths of 183 pm. In the [Mo₂Br₆S₂(NO)₂]^2? ion one of the two nitrosyl groups at each metal atom is substituted by a terminal sulfido ligand with a Mo? S bond length of 240 pm. The i.r. spectra are reported.     

Die Bromokomplexe von Molybdän(IV) [MoBr6]2⊖ und [Mo2Br10]2⊖. Die Kristallstruktur von (PPh3Me)2[MoBr6] · 2 CH2Br2

Bromo Complexes of Molybdenum(IV) [MoBr₆]^2? and [Mo₂Br₁₀]^2?. Crystal Structure of (PPh₃Me)₂[MoBr₆] · 2 CH₂Br₂ The bromomolybdates(IV) (PPh₃Me)₂[MoBr₆] · 2 CH₂Br₂ and (PPh₄)₂[Mo₂Br₁₀] are obtained by reactions of molybdenum tetrabromide with PPh₃MeBr and PPh₄Br, respectively. They form black-brown, hydrolysis sensitive crystal powders. The crystal structure of (PPh₃Me)₂[MoBr₆] · 2 CH₂Br₂ was determined by X-ray diffraction (2376 independent observed reflexions, R = 0.082). Crystal data: a = 1024, b = 1131, c = 1179 pm, α = 108.2°, β = 106.8°, γ = 99.0°, space group P1 , Z = 1. The compound consists of PPh₃Me⁺ ions, CH₂Br₂ molecules and nearly octahedral [MoBr₆]^2? ions with MoBr bond lengths between 252.7 and 254.0 pm.     

Synthese und Kristallstruktur von (PPh4)2[Mo2Cl10]

Synthesis and Crystal Structure of (PPh₄)₂[Mo₂Cl₁₀] The title compound is obtained in the reaction of [MoCl₄(Ph? C?C? Ph)]₂ with tetraphenylphosphonium chloride in dichloro methane, forming brown crystals. It is characterized by the i.r. spectrum and a crystal structure analysis by the aid of X-ray diffraction data. The complex crystallizes triclinic in the space group P1 with one formula unit per unit cell. The cell dimensions are a = 1122 pm, b = 1137 pm, c = 1283 pm; α = 63.4°, β = 69.1°, γ = 86.5°. The crystal structure determination (2959 observed, independent reflexions, R = 4.5%) shows the constants of the unit cell to consist of on centrosymmetric anion, two cations and one disordered molecule of dichloro methane. The distance Mo? Mo in the anion is 380 pm, which excludes direct magnetic interaction between the molybdenum atoms.     

Disulfidoverbrückte Halogenokomplexe von Molybdän(V) Kristallstrukturen von (PPh3Me)2[Cl4Mo(μ-S2)2MoCl4] · 2 CH2Cl2 und (PPh4)2[Br4Mo(μ-S2)2MoBr4] · 3 CH2Br2

Disulfido-Bridged Halo Complexes of Molybdenum (V). Crystal Sructures of (PPh₃Me)₂ [Cl₄Mo (μ-S₂)₂MoCl₄]. 2 CH₂Cl₂ and (PPh₄)₂[Br₄Mo(μ-S₂)₂MoBr₄]. 3CH₂Br₂ . Mo(S₂)Cl₃ is prepared by an improved method; the i.r. spectrum is reported. In dichloro methane solution it reacts with (PPh₃Me)Cl forming the complex (PPh₃Me)₂[Cl₄Mo(μ-S₂)₂MoCl₄] · 2 CH₂Cl₂. The bromo complex (PPh₄)₂[Br₄Mo(μ-S₂)₂MoBr₄] · 3 CH₂Br₂ is obtained by reaction of MoBr₄ with S₇NH and subsequent treatment of the reaction mixture with PPh₄Br in CH₂Br₂ solution. Both complexes are characterized by i.r. spectra and structural analyses by X-ray methods. (PPh₃Me)₂[Cl₄Mo(μ-S₂)₂MoCl₄] · 2 CH₂Cl₂ crystallizes monoclinic in the space group P2₁/c with two formula units per unit cell (5268 observed independent reflexions, R = 4.0%). The lattice dimensions are: a = 1097 pm, b = 1510 pm, c = 1591 pm, β = 104.4°. (PPh₄)₂[Br₄Mo(μ-S₂)₂MoBr₄] · 3 CH₂Br₂ crystallizes triclinic in the space group P&1macr; with two formula units per unit cell and the lattice constants a = 1328 pm, b = 1573 pm, c = 1719 pm, α = 95.8°, β = 96.3°, γ = 74.1°. Both compounds are of ionical structure with PPh₃Me^⊕ and PPh₄^⊕ cations, respectively, and anions [X₄MO(μ-S₂)₂MoX₄]^2? very similar to each other. The molybdenum atoms are bridged by two disulfido ligands and are bonded directly with a bond length of 286 pm. The terminal halogen atoms add up to coordination number nine at the molybdenum.     

Synthese und Struktur von Mo2NCl7

Synthesis and Structure of Mo₂NCl₇ The reaction of VN with MoCl₅ at 175 °C in a sealed glass ampoule yields the molybdenum(V) nitride chloride Mo₂NCl₇ in form of air sensitive black crystals with the triclinic space group P1¯ and a = 905.7(8); b = 975.4((6); c = 1283.4(8) pm, α = 103.13(4)°; β = 109.83(5)° und γ = 98.58(5)°. The crystal structure is built up from dinuclear units [Mo₂N₂Cl₇]^3— and [Mo₂Cl₇]³⁺, which are connected by asymmetric nitrido bridges to form endless chains. Within both dinuclear units the Mo atoms are bridged by three Cl atoms resulting in a Mo‐Mo distance of 349.2(3) pm in the unit [Mo₂N₂Cl₇]^3—. In case of [Mo₂Cl₇]³⁺, however, a shorter Mo‐Mo distance of 289.4(3) pm is observed, which can be interpreted by a single bond. Correspondingly a reduced magnetic moment of 0.95 B.M. per Mo atom is observed.     

Synthese und Eigenschaften von Dimolybdän-μ-nitrido-heptachlorid Mo2NCl7

Synthesis and Properties of Di-molybdenum-μ-nitrido-heptachloride, Mo₂NCl₇ Mo₂NCl₇ was prepared by the reaction of molybdenum pentachloride with the bromide of Millon's base, [Hg₂N]Br, in boiling CCl₄. It forms a moisture sensitive, dark green crystal powder, the magnetic moment at 20°C (μ_eff = 0.95 B.M.) being strongly reduced. With acetonitrile the μ-nitrido complex Mo₂NCl₇ · 3CH₃CN is formed, with phosphoryl chloride the donor acceptor complex Mo₂NCl₇ · 2POCl₃, respectively. Partial oxidation of the latter complex with chlorine leads to very unstable Mo₂NCl₈ · 2POCl₃, from which (PPh₄)₃[Mo₃NCl₁₀] can be obtained by the reaction with PPh₄Cl. For the complex (PPh₄)₃[Mo₂NCl₁₀] is also found a reduced paramagnetism of μ_eff = 1.47 B.M. at 20°C. All complexes are characterized by i.r. spectroscopy.     

Synthese und Struktur von Mo2NCl8 und Mo3N2Cl11

Synthesis and Crystal Structure of Mo_2<>NCl₈ and Mo₃N₂Cl₁₁ The reaction of MoCl₅ with Cl₃VNCl at 140 °C in a sealed glass ampoule yields air sensitive black crystals of the mixed valent molybdenum(V, VI) nitride chloride, Mo₂NCl₈. It crystallizes in the monoclinic space group P2/c with a = 996.1(1), b = 629.4(1), c = 1780.8(3) pm, β = 101.82(2)°, and Z = 4. The crystal structure consists of dinuclear C₂‐symmetrical units [Cl₂(N≡)Mo(μ₂‐Cl)₃Mo(≡N)Cl₂]^— and [Cl₄Mo(μ₂‐Cl)MoCl₄]⁺, connected in an alternating sequence by asymmetric nitrido bridges Mo≡N‐Mo to form chains. The reaction of Cl₃VNCl with MoCl₃ at 140 °C affords Mo₃N₂Cl₁₁, but for the prolonged reaction period, MoNCl₃ is observed in addition. Mo₃N₂Cl₁₁ can also be obtained from MoNCl₃ and MoCl₅ (2:1) at 140 °C. It forms orthorhombic, black crystals with the space group Pca2₁ and a = 1256.1(1), b = 1001.9(1), c = 1330.10(5) pm, and Z = 4. The structure contains the same dinuclear units [Cl₂(N≡)Mo(μ₂‐Cl)₃Mo(≡N)Cl₂]^— as in Mo₂NCl₈, which in this case are connected with MoCl₄⁺ moieties by asymmetric nitrido bridges Mo≡N‐Mo forming chains. In Mo₂NCl₈ the Mo‐N distances in the nearly linear nitrido bridges are 167.6(2), and 214.8(2) pm, whereas in case of Mo₃N₂Cl₁₁ two sets of Mo‐N distances of 166, 8(4) and 214, 0(4) pm as well as 166, 9(4) and 211, 9(4) pm are observed.     

Synthese und Kristallstrukturen der Polyselenidokomplexe (PPh4)6[M(Se4)2]2[WSe4] · DMF mit M = Zink und Quecksilber

Syntheses and Crystal Structures of the Polyselenido Complexes (PPh₄)₆[M(Se₄)₂]₂[WSe₄] · DMF with M = Zinc and Mercury The title compounds have been prepared by the reactions of the acetates of zinc and mercury, respectively, with excess (PPh₄)₂ WSe₄ in boiling dimethylformamide, forming black-red single crystals. According to the X-ray structure determinations both compounds crystallize isotypically in the space group 12/a with four formula units per unit cell. (PPh₄)₆[Zn(Se₄)₂]₂[WSe₄] · DMF: a = 2888.1(6), b = 1740.3(2), c = 2893.9(4) pm, β = 90.47(1)°. 3230 observed unique reflections, R = 0.009. (PPh₄)₆[Hg(Se₄)₂]₂[WSe₄] · DMF: a = 2891.8(5), b = 1738.0(4), c = 2920.1(5) pm, β = 90.29(2)°. 2978 observed unique reflections, R = 0.115%. The compounds consist of PPh₄⁺ ions, spirocyclic octaseleno metallates [M(Se₄)₂]^2?, tetrahedral WSe₄²-ions, and disordered DMF Molecules.     

(PPh4)2[MoN(N3)3Cl]2; Synthese,IR-Spektrum und Kristallstruktur

(PPh₄)₂[MoN(N₃)₃Cl]₂; Synthesis, IR Spectrum, and Crystal Structure The title compound is formed in the reaction of molybdenum (II) benzoate with trimethylsilyl azide and PPh₄Cl in dichloro methane forming dark red single crystals. A PPh₃Me⊕ salt of the ion [MoN(N₃)₃Cl]₂^2? is obtained from (PPh₃Me)₂MoNCl₄] treated with silver azide in CH₂Cl₂ suspension. The solvent CH₂Cl₂ participates in both reactions as oxidizing agent. (PPh₄)₂[MoN(N₃)₃Cl₂ is characterized by a structural analysis based upon X-ray data: space group P1 , Z = 1, a = 1050.7 pm; b = 1185.4 pm; c = 1190.8 pm; α = 98.90°; β = 106.87°; γ = 103.97° (4505 independent, observed reflexions, R = 0.039). The compound consists of PPh₄⊕ cations and centrosymmetric anions [MoN(N₃)₃Cl₂^2? in which the molybdenum atoms are bridged by the N_α atoms of two azide groups; the resulting Mo? N bond lengths are 208 pm and 260 pm. In trans position to the long Mo? N bond the terminal nitrido ligand is situated, the Mo?N distance of 164 pm corresponds to a triple bond. Two terminal azido ligands and the chloro ligand are filling up the coordination sphere of the molybdenum atoms to a coordination number of six. The i.r. spectrum is reported and assigned.     

Die Kristallstrukturen von [ReCl4(PhCCPh)]2 · 2 CH2Cl2 und von PPh4[ReOCl4]

Crystal Structures of [ReCl₄(PhC?CPh)]₂ · 2 CH₂Cl₂ and PPh₄[ReOCl₄] Single crystals of [ReCl₄(PhC?CPh)]₂ · 2 CH₂Cl₂ were obtained by chilling dilute solutions of the solvate [ReCl₄(PhC?CPh)POCl₃] in CH₂Cl₂. PPh₄[ReOCl₄] was formed by the reaction of the diphenyl acetylene complex [ReCl₅(PhC?CPh)] with PPh₄Cl · H₂O in CH₂Cl₂ solution. [ReCl₄(PhC?CPh)]₂ · 2 CH₂Cl₂: space group P2₁/c, Z = 2, 2244 observed independent reflexions, R = 0.038. Lattice parameters (19°C): a = 987.2 pm; b = 1533.9 pm; c = 1193.8 pm; β = 90.17° The compound forms centrosymmetrical dimeric molecules with ReCl₂Re bridges with Re? Cl distances of 241.2 and 267.6 pm. The longer Re? Cl bond is situated in trans-position to the equatorial, side-on coordinated diphenyl acetylene ligand with mean Re? C distances of 200 pm. PPh₄[ReOCl₄]: space group P4/n, Z = 2, 1487 observed, independent reflexions, R = 0.047. Lattice parameters (19°C): a = b = 1272.0 pm; c = 771.3 pm. The compound crystallizes in the AsPh₄[RuNCl₄] type; it consists of [ReOCl₄]^? anions and PPh₄⁺ cations. The anions are tetragonal with C_4v symmetry and bond lengths Re? O = 165.4 pm and Re? Cl = 232.6 pm; the bond angle OReCl is 106.7°.     

(NH4)3[M2NCl10] (M = Nb,Ta): Synthese,Kristallstruktur und Phasenumwandlung

(NH₄)₃[M₂NCl₁₀] (M = Nb, Ta): Synthesis, Crystal Structure, and Phase Transition The nitrido complexes (NH₄)₃[Nb₂NCl₁₀], and (NH₄)₃[Ta₂NCl₁₀] are obtained in form of moisture-sensitive, tetragonal crystals by the reaction of the corresponding pentachlorides with NH₄Cl at 400 °C in sealed glass ampoules. Both compounds crystallize isotypically in two modifications, a low temperature form with the space group P4/mnc and a high temperature form with space group I4/mmm. In case of (NH₄)₃[Ta₂NCl₁₀] a continuous phase transition occurs between –70 °C and +60 °C. For the niobium compound this phase transition is not yet fully completed at 90 °C. The structure of (NH₄)₃[Nb₂NCl₁₀] was determined at several temperatures between –65 °C und +90 °C to carefully follow the continuous phase transition. For (NH₄)₃[Ta₂NCl₁₀] the structure of the low temperature form was determined at –70 °C, and of the high temperature form at +60 °C. The closely related crystal structures of the two modifications contain NH₄⁺ cations and [M₂NCl₁₀]^3– anions. The anions with the symmetry D_4h are characterized by a symmetrical nitrido bridge M=N=M with distances Nb–N = 184.5(1) pm at –65 °C or 183.8(2) pm at 90 °C, and Ta–N = 184.86(5) pm at –70 °C or 184.57(5) pm at 60 °C.     

Ein- und zweikernige Dinitrosylkomplexe von Molybdän und Wolfram. Die Kristallstrukturen von (PPh3Me)2[WCl4(NO)2], (PPh3Me)2[MoCl3(NO)2]2 und von (PPh3Me)2[WCl3(NO)2]2

Mono- and Binuclear Dinitrosyl Complexes of Molybdenum and Tungsten. Crystal Structures of (PPh₃Me)₂[WCl₄(NO)₂], (PPh₃Me)₂[MoCl₃(NO)₂]₂, and (PPh₃Me)₂[WCl₃(NO)₂]₂ The complexes (PPh₃Me)₂[MCl₄(NO)₂] (M = Mo, W), and (PPh₃Me)₂[MCl₃(NO)₂]₂, respectively, are prepared by reactions of the polymeric compounds MCl₂(NO)₂ with triphenylmethylphosphonium chloride in CH₂Cl₂, forming green crystals. According to the IR spectra the nitrosyl groups are in cis-position in all cases. The tungsten compounds as well as (PPh₃Me)₂[MoCl₃(NO)₂]₂ were characterized by structure determinations with X-ray methods. (PPh₃Me)₂[WCl₄(NO)₂]: space group C2/c, Z = 4. a = 1874, b = 1046, c = 2263 pm, β = 119.99°. Structure determination with 3492 independent reflexions, R = 0.057. The compound consists of PPh₃Me^⊕ ions, and anions [WCl₄(NO)₂]^2? with the nitrosyl groups in cis-position (symmetry C_2v). (PPh₃Me)₂[WCl₃(NO)₂]₂: Space group C2/c, Z = 4. Structure determination with 2947 independent reflexions, R = 0.059. (PPH₃Me)₂[MoCl₃(NO)₂]₂: Space group P1 , Z = 1. a = 989, b = 1134, c = 1186 pm; α = 63.25°, β = 80.69°, γ = 69.94°. Structure determination with 3326 independent reflexions, R = 0.046. The compounds consist of PPh₃Me^⊕ ions, and centrosymmetric anions [MCl₃(NO)₂]₂^2?, in which the metal atoms are associated via MCl₂M bridges of slightly different lengths. One of the NO groups is in an axial position, the other one in equatorial position (symmetry C_2h).     

Reaktionen von Uranpentabromid Die Kristallstrukturen von PPh4[UBr6], PPh4 [UBr6] · 2CCl4, (PPh4)2[UBr6] · 4CH3CN und (PPh4)2[UO2Br4] · 2CH2Cl2

Reactions of Uranium Pentabromide. Crystal Structures of PPh₄[UBr₆], PPh₄[UBr₆] · 2CCl₄, (PPh₄)₂[UBr₆] · 4CH₃CN, and (PPh₄)₂[UO₂Br₄] · 2CH₂Cl₂ PPh₄[UBr₆] and PPh₄[UBr₆] · 2CCl₄ were obtained from UBr₅ · CH₃CN and tetraphenylphosphonium bromide in dichloromethane, the latter being precipitated by CCl₄. Their crystal structures were determined by X-ray diffraction. PPh₄[UBr₆]: 2101 observed reflexions, R = 0.090, space group C2/c, Z = 4, a = 2315.5, b = 695.0, c = 1805.2 pm, β = 96.38°. PPh₄[UBr₆] · 2CCl₄: 2973 reflexions, R = 0.074, space group P2₁/c, Z = 4, a = 1111.5, b = 2114.2, c = 1718.7 pm, β = 95.42°. Hydrogen sulfide reduces uranium pentabromide to uranium tetrabromide. Upon evaporation, bromide is evolved from solutions of UBr₅ with 1 or more then 3 mol equivalents of acetonitrile in dichlormethane yielding UBr₄ · CH₃CN and UBr₄ · 3CH₃CN, respectively. These react with PPh₄Br in acetonitrile affording (PPh₄)₂[UBr₆] · 4CH₃CN, the crystal structure of which was determined: 2663 reflexions, R = 0.050, space group P2₁/c, Z = 2, a = 981.8, b = 2010.1, c = 1549.3 pm, β = 98.79°. By reduction of uranium pentabromide with tetraethylammonium hydrogen sulfide in dichloromethane (NEt₄)₂[U₂Br₁₀] was obtained; (PPh₄)₂[U₂Br₁₀] formed from UBr₄ and PPh₄Br in CH₂Cl₂. Both compounds are extremely sensitive towards moisture and oxygen. The crystal structure of the oxydation product of the latter compound, (PPh₄)₂[U0₂Br₄]· 2 CH₂Cl₂, was determined: 2163 reflexions, R = 0.083, space group C2/c, Z = 4, a = 2006.3, b = 1320.6, c = 2042,5 pm, β = 98.78°. Mean values for the UBr bond lengths in the octahedral anions are 266.2 pm for UBr₆-, 276.7 pm for UBr₆^2? and 282.5 pm for UO₂Br₄^2?     

Thiobromokomplexe von Arsen und Antimon Darstellung und Kristallstrukturen von (PPh4)2[As2SBr6] · CH2Br2 und (PPh4)2[Sb2SBr6] · CH2Br2

Thiobromo Complexes of Arsenic and Antimony. Preparation and Crystal Structures of (PPh₄)₂[As₂SBr₆] · CH₂Br₂ and (PPh₄)₂[Sb₂SBr₆] · CH₂Br₂ (PPh₄)₂[As₂SBr₆] · CH₂Br₂ is formed by the reaction of As₂S₃, PPh₄I and HI in dibromomethane. It can also be obtained, as well as (PPh₄)₂[Sb₂SBr₆] · CH₂Br₂, from (PPh₄)₂[As₂Br₈] and (PPh₄)₃[Sb₂Br₉], respectively, with bistrimethylsilylsulfide. The crystal structures of the title compounds were determined by X-ray diffraction. They are isotypic with (PPh₄)₂[As₂SCl₆] · C₂H₄Cl₂. In the anions [M₂SBr₆]^2? the M atoms (As or Sb) have a distorted octahedral coordination, the two octahedra share acommon face with one bridging S and two Br atoms; the lone electron pairs occupy the trans positions to the S atom. Crystal data: triclinic, space group P1 , Z = 2; (PPh₄)₂[As₂SBr₆] · CH₂Br₂, a = 119.1, b = 1203.6, c = 2067.5 pm α= 94.89, β = 97.78, γ = 112.20°, 3046 independent observed reflexions, R = 0.083; (PPh₄)₂[Sb₂SBr₆] · CH₂Br₂, a = 1198.9, b = 1224.3, c = 2085.5pm, α = 95.04, β = 98.48, γ = 112.13°C, 2380 reflexions, R = 0.079.     

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.     

IV Dodekaedrische [Mo(CN)8]‐Koordination in den cyanoverbrückten Cobalt‐ und Nickel‐Amminkomplexen MII2(NH3)8[Mo(CN)8] · 1,5 H2O (MII = Co,Ni) und Ni2(NH3)9[Mo(CN)8] · 2 H2O

Crystal Structures of Octacyanomolybdates(IV). IV Dodecahedral [Mo(CN)₈] Coordination of the Cyano‐Bridged Cobalt and Nickel Ammin Complexes M^II₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (M^II = Co, Ni) and Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O At single crystals of the hydrated cyano complexes Co₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 910.0(4), b = 1671(2), c = 1501(1) pm, β = 93.76(6)°) and Ni₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 899.9(9), b = 1654.7(4), c = 1488(1) pm, β = 94.01°), isostructurally crystallizing in space group P2₁/c, Z = 4, and of trigonal Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O (a = 955.1(1), c = 2326.7(7) pm, P3₁, Z = 3), X‐ray structure determinations were performed at 168 resp. 153 K. The [Mo(CN)₈]^4– groups of the three compounds, prepared at about 275 K and easily decomposing, show but slightly distorted dodecahedral coordination (mean distances Mo–C: 216.3, 215.4 and 216.1 pm). Within the monoclinic complexes the anions twodimensionally form cyano bridges to the ammin cations [M(NH₃)₄]²⁺ and are connected with the resulting [MN₆] octahedra (Co–N: 215.1 pm, Ni–N: 209.8 pm) into strongly puckered layers. The trigonal complex exhibits a chain structure, as one [Ni(NH₃)₅]²⁺ cation is only bound as terminal octahedron (Ni–N: 212.0 pm). Details and the influence of hydrogen bridges are discussed.     

Synthese und Kristallstruktur von (PPh4)2[Mo2(S2)2Cl8] · 2 CH3CN und seine topotaktische Umwandlung zu (PPh4)2[Mo2(S2)2Cl8]

Synthesis and Crystal Structure of (PPh₄)₂[Mo₂(S₂)₂Cl₈] · 2 CH₃CN and its Topotactic Transformation to (PPh₄)₂[Mo₂(S₂)₂Cl₈] MoS₂Cl₃ was prepared from molybdenum and S₂Cl₂ at 200 °C. Its reaction with PPh₄Cl in acetonitrile yielded (PPh₄)₂[Mo₂(S₂)₂Cl₈] · 2 CH₃CN. In vacuum or upon warming, it loses the acetronitrile without degradation of the crystals. According to the X-ray crystal structure determinations both compounds, with and without acetonitrile, are triclinic. They contain the same [Cl₄Mo(μ-S₂)₂MoCl₄]^2– ions, in which the Mo atoms are joined by two disulfido groups and an Mo–Mo bond. Details of the crystal packings and their topotactic transformation are given.     

Synthese und Kristallstruktur von (PPh4)2Se6

Synthesis and Crystal Structure of (PPh₄)₂Se₆ (PPh₄)₂Se₆ has been prepared by the reaction of selenium with K₂Se₂ in dimethylformamide solution in the presence of K₃[Mn(CN)₆] and PPh₄Br, forming black crystal needles. According to the crystal structure determination the compound consists of PPh⁺₄ ions and chainlike hexaselenide ions. Space group P6 , Z = 2,4683 Observed unique reflections, R = 0.066. Lattice dimensions at ?90°C: a = 951.0, b = 1094.8, c = 2137.4 pm, α = 82.66°, β = 83.36°, γ = 89.96°.