Thiohalogeno-Verbindungen von Niob und Tantal: NbSCl3, TaSCl3, [NbSCl5]2−, [TaSCl5]2−, [NbSBr4]− Die Kristallstrukturen von (PPh4)2[NbSCl5] · 2 CH2Cl2 und NEt4[NbCl6]

Thiohalo Compounds of Niobium and Tantalum: NbSCl₃, TaSCl₃, [NbSCl₅]^2?, [TaSCl₅]^2?, [NbSBr₄]^?. Crystal Structures of (PPh₄)₂[NbSCl₅] · 2 CH₂Cl₂ and NEt₄[NbCl₆] NbSCl₃ can be obtained from NbCl₅ by reaction with H₂S or bistrimethylsilyl sulfide in a suspension of CCl₄ or CH₂Cl₂, respectively; in the latter case the product contains a rest of trimethylsilyl groups. This also applies for TaSCl₃, NbSBr₃ and TaSBr₃, which are formed from the metal pentahalides and S(SiMe₃)₂. NEt₄[NbSCl₄] is formed together with NEt₄[NbCl₆] in the reaction of NbCl₅ with NEt₄SH in CH₂Cl₂. PPh₄[NbCl₆] reacts with S(SiMe₃)₂ in dichloromethane yielding (PPh₄)₂[NbSCl₅] · 2 CH₂Cl₂, whereas PPh₄[NbSBr₄] is obtained from PPh₄[NbBr₆] and S(SiMe₃) under the same conditions. (PPh₄)₂[TaSCl₅] · 2 CH₂Cl₂ was obtained from TaSCl₃ and PPh₄Cl in CH₂Cl₂. According to an X-ray crystal structure determination (PPh₄)₂[NbSCl₅] · 2 CH₂Cl₂ crystallizes in the β-(AsPh₄)₂[UCl₆] · 2 CH₂Cl₂ type with positionally disordered, octahedral anions. Crystal data: a = 1 021.7, b = 1120.4, c = 1 243.3 pm, α = 70.77, β = 80.24, γ = 80.54°, space group P1 , Z = 2; 2462 unique observed reflexions, R = 0.036. NEt₄[NbCl₆] crystallizes isotypic to NEt₄[WCl₆], a = 723.5, b = 1 018.0, c = 1 174.6 pm, β = 100.07°, space group P2₁/n, Z = 2; 1 875 reflexions, R = 0.075.     

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.     

Thiochloro-Verbindungen von fünfwertigem Niob und Wolfram: WSCl3, [WSCl4]22−, [NbSCl4]− Die Kristallstruktur von PPh4[NbSCl4]

Thio-chloro Compounds of Pentavalent Niobium and Tungsten: WSCl₃, [WSCl₄]₂^2?, [WSCl₅]^2?, [NbSCl₄]^?. Crystal Structure of PPh₄[NbSCl₄] Black WSCl₃ was obtained by reduction of (WSCl₄)₂ with C₂Cl₄. With PPh₄Cl in CH₂Cl₂ it yields (PPh₄)₂[WSCl₄]₂ which has a dimeric structure with chloro bridges according to its i. r. spectrum. Iodide reduces PPh₃Me[WSCl₅] in CH₂Cl₂ to (PPh₃Me)₂[WSCl₅], from which (PPh₃Me)₂[WSBr₅ · BBr₃] is obtained by reaction with BBr₃. From PPh₄Cl in CH₂Cl₂ and raw NbSCl₃ (obtained by solid state reaction of NbCl₅ with B₂S₃) PPh₄[NbSCl₄] is formed. The crystal structure of PPh₄-[NbSCl₄] was determined and refined with X-ray diffraction data (residual index R = 0.066 for 1017 reflexions). It crystallizes in the AsPh₄[RuNCl₄] structure type (space group P4/n) with the lattice constants a = 1303 and c = 760 pm. The quadratic-pyramidal [NbSCl₄]^? ion has a Nb?S bond length of 209 pm. The i. r. spectra of all compounds are discussed.     

Darstellung und elektrochemisches Verhalten von [Nb(OTeF5)6]− und [Ta(OTeF5)6]−-Komplexen

Preparation and Electrochemistry of [Nb(OTeF₅)₆]^? and [Ta(OTeF₅)₆]^? Complexes Nb(OTeF₅)₅ and Ta(OTeF₅)₅ react with Cs[OTeF₅], [Et₄N][OTeF₅], and [(n-Bu)₄N][OTeF₅] to the corresponding Cs[M(OTeF₅)₆], [Et₄N][M(OTeF₅)₆], and [(n-Bu)₄N][M(OTeF₅)₆] complexes, (M = Nb, Ta). The electrochemical reduction of the niobium complex occurs in CH₂Cl₂ at ?0,69 V and in acetonitrile at ?0,60 V (vs. SCE). The tantalum complex is reduced in CH₂Cl₂ at ?1,52 V and in acetonitrile at ?1,42 V (vs. SCE).     

Neue Synthesewege für Thiohalogeno- und Cyclothioarsenate(III). Kristallstrukturen von PPh4[As2SBr6] · CH3CN und PPh4[SAsS5]

Novel Routes to the Synthesis of Thiohalogeno- and Cyclothioarsenates(III). Crystal Structures of PPh₄[As₂SBr₆] · CH₃CN and PPh₄[SAsS₅] By reactions of (PPh₄)₂[As₂Cl₈] and (PPh₄)₂[As₂Br₈] with Na₂S₄ in acetonitrile (PPh₄)₂[As₂SCl₆] · CH₃CN and (PPh₄)₂[As₂SBr₆] · CH₃CN were obtained, respectively. Using K₂S₅, PPh₄[As₂SCl₅] and PPh₄[SAsS₅] were the products. The latter can also be obtained from PPh₄[As₂SCl₅] and Na₂S₄, while PPh₄[As₃S₃Br₄] is formed from PPh₄[As₂SBr₅] with K₂S₅. Two X-ray crystal structure determinations were performed. PPh₄[As₂SBr₆] · CH₃CN: triclinic, P1 , Z = 2, a = 1200.4(7), b = 1507.3(6), c = 1594.4(8) pm, α = 81.59(2), β = 78.22(3), γ = 80.58(2)°, R = 0.096 for 2298 observed reflexions. The structure contains [As₂SBr₆]^2? -ions in which the two Sb atoms are joined via one S and two Br atoms. PPh₄[SAsS₅]: triclinic, P1 , Z = 2, a = 1133.9(4), b = 1142.5(4), c = 1186.9(5) pm, α = 102.77(4), β = 107.74(3), γ = 106.65(3)°, R = 0.043 für 2677 reflexions. In the [SAsS₅]^? -ion an AsS₅ ring in the chair conformation is present.     

Binary Pnictogen Azides—An Experimental and Theoretical Study: [As(N3)4]−, [Sb(N3)4]−, and [Bi(N3)5(dmso)]2−

[PPh₄][EI₄] (E=As, Sb, Bi) salts were reacted with four and five equivalents of AgN₃ to form tetraazidopnictates and pentaazidopnictates of the type [PPh₄][E(N₃)₄] and [PPh₄]₂[E(N₃)₅], respectively. The synthesis of [PPh₄][P(N₃)₄] was also attempted from the reaction of P(N₃)₃ with [PPh₄]N₃, but it yielded only the starting materials. Herein, we report the synthesis and structure elucidation of [PPh₄][E(N₃)]₄ (E=As, Sb) and pentaazidobismuthate, stabilized as the dimethyl sulfoxide (DMSO) anion adduct, [PPh₄]₂[Bi(N₃)₅(dmso)]. Successive anion formation along the series E(N₃)₃+nN₃^? (n=1–3) and E(N₃)₅+N₃^? was studied by density functional theory.     

Nitrosylbromokomplexe des Rheniums: Re(NO)2Br3 und [Re(NO)2Br4]⊖; die Kristallstruktur von PPh4[Re(NO)2Br4] · 2 CCl4

Nitrosyl Bromo Complexes of Rhenium: Re(NO)₂Br₃ and [Re(NO)₂Br₄]^?; Crystal Structure of PPh₄[Re(NO)₂Br₄] · 2 CCl₄ PPh₄[Re(NO)₂Br₄] is prepared in the form of dark red-brown powder by the reaction of PPh₄[Re(NO)₂Cl₄] with excess boron tribromide. From a solution of CH₂Br₂ and CCl₄ it crystallizes with two moles CCl₄, one of which splits off easily in vacuo. The reaction of aluminum tribromide in CH₂Br₂ solution leads to a slightly soluble red-brown Re(NO)₂Br₃ powder. The i.r. spectra indicate cis positions of the covalently bound NO ligands in both complexes. Re(NO)₂Br₃ is dimeric via bromo bridges. The crystal structure determination of PPh₄[Re(NO)₂Br₄] · 2 CCl₄ was solved by X-ray diffraction methods at ? 115°C. The complex crystallizes in the monoclinic space group P2₁/c with four formula units per unit cell (4434 independent reflexions, R = 0.085). The unit cell dimensions are a = 1 092.3 pm, b = 2088.0 pm, c = 1 657.6 pm, β = 96.10°. The structure consists of P(C₆H₅)₄^? cations, [Re(NO)₂Br₄]^? anions and intercalated CCl₄ molecules. In the anion the NO groups are covalently bound to the Re atom like \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {{\rm RE}}\limits^ \ominus = \mathop {\rm N}\limits^ \oplus = {\rm O} $\end{document} and they are arranged in cis position to one another.     

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.     

Darstellung und Schwingungsspektren von Dichloro- und Dibromodithiophosphat Die Kristallstrukturen von [PPh3Me] [PS2Cl2] und [PPh4] [PS2Br2]

Preparation and Vibrational Spectra of Dichloro and Dibromodithiophosphate. Crystal Structures of [PPh₃Me][PS₂Cl₂] and [PPh₄][PS₂Br₂] Dichloro and dibromodithiophosphates [Cat⁺][PS₂X₂^?] with a large organic cation can be obtained from P₄S₁₀, CatX and HX in CH₂Cl₂ (Cat⁺ = PPh₄⁺, PPh₃Me⁺; X = Cl, Br). The vibrational spectra (i.r. and Raman) of the [PS₂X₂]^? ions are reported and discussed; force constants were calculated. The crystal structures of [PPh₃Me][PS₂Cl₂] and [PPh₄][PS₂Br₂] were determined and refined with X-ray diffraction data. In both cases, simple anions [PS₂X₂]^? are present. [PPh₃Me][PS₂Cl₂]: orthorhombic, space group P2₁2₁2₁, a = 1089, b = 1334, c = 1476 pm, Z = 4, refinement to a residual index R = 0.046 for 1116 reflexions; the structure is isotopic with [PPh₃Me][VO₂Cl₂]. [PPh₄][PS₂Br₂]: tetragonal space group I4 , a = 1301, c = 721 pm, Z = 2, refinement to R = 0.065 for 357 reflexions; the structure is isotypic with [AsPh₄][FeCl₄] with [PS₂Br₂]^? ions occupying positions of 4 -symmetry with statistical orientation (statistical superposition of Br and S positions).     

Synthese und Struktur des μ-Sulfido-μ-disulfido-octabromodiwolframat(V)-Ions [W2S3Br8]2−

Synthesis and Structure of μ-Sulfido-μ-disulfido-octabromoditungstate(V), [W₂S₃Br₈]^?2 Tungsten hexabromide reacts with H₂S in dichloromethane yielding a brown product which, by addition of tetraphenylphosphonium bromide in CH₂Cl₂, is converted to brown, crystalline (PPh₄)₂[Br₄W(μ-S)(μ-S₂)WBr₄] · CH₂Cl₂ · CH₂S. Its IR spectrum is reported, its crystal structure was determined by X-ray diffraction (2330 reflexions, R = 0.097). Crystal data: orthorhombic, Pnma, a = 1 766.5, b = 2 412.7, c = 1 416.3 pm, Z = 4. In the diamagnetic [W₂S₃Br₈]^2? ions the two W atoms are linked via a sulfido and a disulfido bridge and by a W? W bond.     

Nitrido-Azido-Komplexe des Molybdän(VI): Synthese und Kristallstruktur von [MoN(N3)2(terpy)]+ [MoN(N3)4]−·MoN(N3)3 (terpy)

Nitrido-Azido-Complexes of Molybdenum(VI). Synthesis and Crystal Structure of [MoN(N₃)₂(terpy)]⁺[MoN(N₃)₄] ^? · MoN(N₃)₃(terpy) (CH₃)₃SiN₃ reacts with Mo(CO)₃(terpy) in CH₃CN yielding red crystals of [MoN(N₃)₂(terpy)]⁺[MoN(N₃)₄] ^?· MoN(N₃)₃(terpy) (space group P1 , a = 1039.3 pm, b = 1384.6 pm, c = 1685.4 pm, α = 112.4°, β = 108.1°, γ = 88.3°, Z = 2, R = 0.035 for 4376 independent reflections). The structure consists of three different mononuclear complexes. In the neutral complex MoN(N₃)₃(terpy) Mo exhibits the coordination number 7 in form of a distorted pentagonal bipyramid, with the terpyridine ligand and two azido groups in the equatorial plane. The axial positions are occupied by the nitrido ligand and another azido group. The triply bonded nitrido nitrogen atom (Mo1? N1 = 165.6 pm) causes a strong trans effect resulting in a long distance of 245.7 pm to N_α of the trans bonded azido group. The cationic complex [MoN(N₃)₂(terpy)]⁺ derives from MoN(N₃)₃-(terpy) by abstraction of the trans bonded azido group. For the molybdenum atom remains the coordination number 6 in form of the rarely found pentagonal pyramid. In the anion [MoN(N₃)₄]^? the molybdenum atom exhibits the coordination number 5 in form of a tetragonal pyramid with the nitrido ligand in the apex. The square basic plane is formed by the N_α atoms of the azido groups.     

PPh4[As3S3Cl4] und PPh4[As3S3Br4]

PPh₄[As₃S₃Cl₄] and PPh₄[As₃S₃Br₄] When As₂S₃ reacts with PPh₄X and HX in 1,2-C₂H₄X₂ (X = Cl, Br), the title compounds are obtained as minor products; the main products are PPh₄[As₂SX₅]. Their crystal structures were determined by X-ray diffraction. PPh₄[As₃S₃Cl₄]: a = 1187.7, b = 1090.9, c = 1191.8 pm, α = 82.91, β = 88,93, γ = 88.52°; twins with twin plane (100); R = 0.109 for 1618 observed reflexions of one twin crystal. PPh₄[As₃S₃Br₄]: a = 1119.7, b = 1177.5, c = 1204.1 pm, α = 81.59, β = 85.88, γ = 88.25°; R = 0.061 for 2331 observed reflexions. Both compounds crystallize in the space group P1 , Z = 2, and can be considered to be isotypic. Nevertheless, PPh₄[As₃S₃Br₄] does not form twins as PPh₄[As₃S₃Cl₄]. The crystals consist of PPh₄⁺ and [As₃S₃X₄]^? ions. In the anions, the three As atoms of an As₃S₃ ring in the chair conformation are commonly joined to an X atom and each As atom is bonded to one further terminal X atom. Cations and anions are packed in alternating layers.     

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?     

Die Kristallstrukturen von [Et3PNAsPh3]2[Ag2Br4] und [Et3PNAsPh3]2[Pd2Br6]

Crystal Structures of [Et₃PNAsPh₃]₂[Ag₂Br₄] and [Et₃PNAsPh₃]₂[Pd₂Br₆] Colourless single crystals of [Et₃PNAsPh₃]₂[Ag₂Br₄]( 1 ) and red single crystals of [Et₃PNAsPh₃]₂[Pd₂Br₆]( 2 ) have been isolated from saturated solutions in acetonitrile of equivalent mixtures of [Et₃PNAsPh₃]Br with AgBr and PdBr₂, respectively. Both complexes were characterized by IR spectroscopy and by crystal structure determinations. 1 : Space group P1¯, Z = 1, lattice dimensions at ‐70°C: a = 985.0(2), b = 1042.2(5), c = 1345.8(5) pm, α = 102.88(2)°, β = 105.73(2)°, γ = 94.94(2)°, R₁ = 0.0577. 2 : Space group P2₁/c, Z = 2, lattice dimension at ‐70°C: a = 1003.0(1), b = 1371.8(2), c = 1974.0(1) pm, β = 93.30(1)°, R₁ = 0.0458. The dimeric anions of 1 and 2 form planar, centrosymmetric complex units.     

Darstellung und Schwingungsspektren von Chloro-Bromo-Dirhodaten(III), [Rh2ClnBr9−n]3−, n = 0–9

Preparation and Vibrational Spectra of Nonahalogenodirhodates(III), [Rh₂Cl_nBr_9-n]^3?, n = 0–9 The pure nonahalogenodirhodates(III), A₃[Rh₂Cl_nBr_9-n], A = K, Cs, (TBA); n = 0–4, 9, have been prepared. They are formed from the monomer chlorobromorhodates(III), [RhCl_nBr_6-n]^3?, n = 0–6, which are bridged to confacial bioctahedral complexes by ligand abstraction in less polar organic solvents. From the mixtures the complexions are separated by ion exchange chromatography on DEAE-cellulose. The solid, air-stable, air-stable, K-, Cs- and (TBA)-salts of [Rh₂Cl_nBr_9-n]^3?, n = 0–4, are green, of [Rh₂Cl₉]^3? are brown. The IR and Raman spectra of [Rh₂Br₉]^3? and [Rh₂Cl₉]^3? are assigned according to the point group D_3h. The chlorobromodirhodates exist as mixtures of geometrical and structural isomers, which belong to different point groups. The vibrational spectra exhibit bands in characteristic regions; at high wavenumbers stretching vibrations with terminal ligands v(Rh—Cl_t): 360–320, v(Rh—Br_t): 280–250; in a middle region with bridging ligands v(Rh—Cl_b): 300–270, v(Rh—Br_b): 210–170 cm^?1; the deformation bands are observed at distinct lower frequencies. The terminal ligands are fixed very strong, and the distance between v(Rh—X_t) and v(Rh—X_b) increases with decreasing size of the cations.     

Pentabromothio-diarsenat und -diantimonat: Darstellung,Schwingungsspektren und Kristallstrukturen von PPh4[As2SBr5] und PPh4[Sb2SBr5]

Pentabromothio-diarsenate and -diantimonate: Preparation, Vibrational Spectra, and Crystal Structures of PPh₄[As₂SBr₅] and PPh₄[Sb₂SBr₅] The title compounds were obtained in CH₂Br₂ from PPh₄Br, HBr and As₂S₃ or Sb₂S₃, respectively. Their i.r. and Raman spectra are reported. Their crystal structures were determined by X-ray diffraction. Crystal data: PPh₄[As₂SBr₅], monoclinic, space group P2₁/n, Z = 4, a = 1192.3, b = 1528.1, c = 1618.0 pm, β = 95.53°, isotypic with PPh₄[As₂SCl₅] (structure determination with 1539 observed reflexions, R = 0.052); PPh₄[Sb₂SBr₅], triclinic, space group P1 , Z = 2, a = 1044,8, b = 1207.1, c = 1307.8 pm, α = 104.77, β = 108.63, γ = 98.34° (2398 observed reflexions, R = 0.032). Both ions, [As₂SBr₅]^? and [Sb₂SBr₅]^?, have the same general structure: including the lone electron pairs, the As and Sb atoms have distorted trigonal-bipyrimidal coordination, two bipyramids sharing a common edge with sulfur and bromine as bridging atoms. The [As₂SBr₅]^? ions are associated to chains via As…Br contacts, the [Sb₂SBr₅]^? ions form pseudodimeric units by Sb…S and Sb…Br contacts. Whereas the crystal packing of the As compound is similar to that of other PPh₄⁺ compounds having a cation to anion ratio of 1:1, the Sb compound shows the packing principle known for 2:1 compounds.     

Synthese,Struktur und Thermolyse von NH4[Re3Br10]

Synthesis, Structure and Thermolysis of NH₄[Re₃Br₁₀] NH₄[Re₃Br₁₀] crystallizes as dark brown single crystals upon slow cooling of a hot, saturated hydrobromic-acid solution of [Re₃Br₉(H₂O)₂] after the addition of NH₄Br. The crystal structure (monoclinic, C2/m (Nr. 12); Z = 4; a = 1461.6(7), b = 1 085.6(4), c = 1030.3(7) pm, β = 92.63(4)°, V_m = 245.9(4)cm³/mol; R = 0.097, R_w = 0.043) contains [Re₃Br₁₂]^? units that share two common edges. These chains run along [010] and are held together by NH₄⁺ ions. Each NH₄⁺ is surrounded by eight Br^? from four different chains. The first step of the thermal decomposition at 290°C is the disproportionation to ReBr₃ (ReCl₃ type), rhenium metal and (NH₄)₂[ReBr₆]. Secondly, the internal reduction of (NH₄)₂[ReBr₆] at 390°C to rhenium metal takes place.     

Neue Kronenether‐stabilisierte Oxoniumhalogenochalkogenate: [H3O(Dibromo‐benzo‐18‐Krone‐6)]2[Se3Br10] und [H5O2(Bis‐dibromo‐dibenzo‐24‐Krone‐8]2[Se3Br8]

Novel Oxonium Halogenochalcogenates Stabilized by Crown Ethers: [H₃O(Dibromo‐benzo‐18‐crown‐6)]₂[Se₃Br₁₀] and [H₅O₂(Bis‐dibromo‐dibenzo‐24‐crown‐8]₂[Se₃Br₈] Two novel complex oxonium bromoselenates(II,IV) and –(II) are reported containing [H₃O]⁺ and [H₅O₂]⁺ cations coordinated by crown ether ligands. [H₃O(dibromo‐benzo‐18‐crown‐6)]₂[Se₃Br₁₀] ( 1 ) and [H₅O₂(bis‐dibromo‐dibenzo‐24‐crown‐8]₂[Se₃Br₈] ( 2 ) were prepared as dark red crystals from dichloromethane or acetonitrile solutions of selenium tetrabromide, the corresponding unsubstituted crown ethers, and aqueous hydrogen bromide. The products were characterized by their crystal structures and by vibrational spectra. 1 is triclinic, space group (Nr. 2) with a = 8.609(2) Å, b = 13.391(3) Å, c = 13.928(3) Å, α = 64.60(2)°, β = 76.18(2)°, γ = 87.78(2)°, V = 1404.7(5) ų, Z = 1. 2 is also triclinic, space group with a = 10.499(2) Å, b = 13.033(3) Å, c = 14.756(3) Å, α = 113.77(3)°, β = 98.17(3)°, γ = 93.55(3)°. V = 1813.2(7) ų, Z = 1. In the reaction mixture complex redox reactions take place, resulting in (partial) reduction of selenium and bromination of the crown ether molecules. In 1 the centrosymmetric trinuclear [Se₃Br₁₀]^2? consists of a central Se^IVBr₆ octahedron sharing trans edges with two square planar Se^IIBr₄ groups. The novel [Se₃Br₈]^2? in 2 is composed of three planar trans‐edge sharing Se^IIBr₄ squares in a linear arrangement. The internal structure of the oxonium‐crown ether complexes is largely determined by the steric restrictions imposed by the aromatic rings in the crown ether molecules, as compared to complexes with more flexible unsubstituted crown ether ligands.     

Azidokomplexe von Mangan(II) und Cobalt(II) Die Kristallstrukturen von (PPh4)2[Mn(N3)4] und (PPh4)2[Co(N3)3Cl]

Azido Complexes of Manganese(II) and Cobalt(II). Crystal Structures of (PPh₄)₂[Mn(N₃)₄] and PPh₄₂[Co(N₃)₃Cl] (PPh₄)₂[Mn(N₃)₄] and (PPh₄)₂[Co(N₃)₃Cl] were obtained as light-brown and green blue, nonexplosive crystalline compounds, respectively. They are only slightly sensitive to moisture and were obtained from the tetrachloro complexes (PPh₄)₂MCl₄ by reactions with silver azide in dichloromethane. The compounds were characterized by thier i.r. spectra and by crystal structure analyses. Both crystallized in the monoclinic space group C2/c, Z = 4, but they are not isotypic. (PPh₄)₂[Mn(N₃)₄]: structure determination with 711 independent reflexions, R = 0.097; a = 2249.1, b = 1499.6, c = 1370.3 pm, β = 104.86°. (PPh₄)₂[Co(N₃)Cl]: 2753 reflexions, R = 0.075; a = 1119.7, b = 1899.2, c = 2115.4 pm, β = 90.47°. The structures consist of PPh₄⁺ ions and of anions that are situated on twofold crystallographic rotation axes. The anions show positional disorder, statistically assuming two different orientations with probabilities of 50% each; in the case of [Co(N₃)₃Cl]^2?, the Cl atom is superimposed statistically with an azido group, whereas the [Mn(N₃)₄]^2? ion is tilted by about 20° from the ideal position to two sides of the crystallographic axis. In both compounds the cation form layers and the anions are located between the layers.     

Ca6GaN5 und Ca6FeN5. Verbindungen mit [CO3]2−-isosteren Anionen [GaN3]c− und [FeN3]6−

Ca₆GaN₅ and Ca₆FeN₅: Compounds Containing [CO₃]^2?-isosteric Anions [GaN₃]^6? and [FeN₃]^6? The isotypic phases Ca₆GaN₅ and Ca₆FeN₅ (hexagonal, P6₃/mem; a = 627.7(3)/ 623,7(1) pm, c = 1219.8(3)/1233.2(6) pm; Z = 2) are prepared by reaction of Ca/Ga mixtures (molar ratio 6:1) and Fe/Ca₃N₂/Ca mixtures (molar ratios from 3:1:13 to 5:2:15) with nitrogen at temperatures of 850°C and 950°C to 1100°C, respectively. The structures contain trigonal-planar anions [MN₃]^6? which are isosteric to carbonate ions (Ga? N: 195,1(28) pm; Fe? N: 177,0(15) pm). The structures are closely related to those compounds of the hydrotalcite group.