Isomerism in tetrahedral rhenium cluster complexes [Re4Q4(PMe2Ph)4X8]·nCH2Cl2 (Q = Se, X = Br; Q = Te, X = Cl, Br)

Three new tetrahedral rhenium cluster compounds [Re₄Se₄(PMe₂Ph)₄Br₈]·1.5CH₂Cl₂ (1), [Re₄Te₄(PMe₂Ph)₄Br₈]·CH₂Cl₂ (2), and [Re₄Te₄(PMe₂Ph)₄Cl₈]·CH₂Cl₂ (3) have been synthesized by the reaction of the corresponding precursor chalcohalide complexes [Re₄Q₄(TeX₂)₄X₈] (X = Br, Q = Se (for 1), Te (for 2); X = Cl, Q = Te (for 3)) with dimethylphenylphosphine in CH₂Cl₂. All compounds have been characterized by X-ray single-crystal diffraction and elemental analyses, IR and ³¹P NMR spectroscopy. ³¹P NMR spectroscopy indicates the formation of isomers in solution, confirmed by single-crystal X-ray analysis.     

Strukturbeziehungen zwischen Tetraselen(2+)‐hexachlorometallaten: Synthese und Kristallstruktur von Se4[ReCl6] und Phasenumwandlung von Se4[MCl6] (M = Zr,Hf)

Structure Relationships between Tetraselenium(2+) Hexachlorometalates: Synthesis and Crystal Structure of Se₄[ReCl₆] and the Solid State Phase Transition of Se₄[MCl₆](M = Zr, Hf). The reaction of Se, SeCl₄, and ReCl₄ in a closed, evacuated glass ampoule at 485 K yields dark‐red moisture sensitive crystals of Se₄[ReCl₆] (orthorhombic, Pccn, a = 1091.5(1), b = 1057.2(1), c = 1015.0(1) pm). The crystal structure consists of almost square‐planar Se₄²⁺ cations and slightly distorted octahedral [ReCl₆]^2— anions. Se₄[ReCl₆] is paramagnetic with a moment of 3.54 μ_B/Re according to a d³ configuration and Re(IV). The magnetic moment obeys the Curie‐Weiss law with a Weiss constant of —33 K. The already known compounds Se₄[ZrCl₆] and Se₄[HfCl₆] crystallize in a closely related structure with tetragonal symmetry (space group P4₂/ncm). Both undergo a phase transition in the solid state into an orthorhombic low temperature form, which is isotypic to Se₄[ReCl₆]. The phase transition was monitored by single crystal and powder diffraction, the transition temperature was determined to 193(1) K for Se₄[ZrCl₆]. The changes of the lattice constants with temperature imply a displacive transition of mainly second order which is allowed by the translationsgleiche supergroup‐subgroup relation of index 2 between the space groups. No phase transition into a tetragonal high‐temperature form could be observed for the orthorhombic Se₄[ReCl₆].     

Bismut(II)-chalkogenometallate(III) Bi2M4X8, Verbindungen mit Bi24+-Hanteln (M = Al,Ga; X = S,Se)

Bismuth(II) Chalcogenometallates(III) Bi₂M₄X₈, Compounds with Bi₂⁴⁺ Dumbbells (M = Al, Ga and X = S, Se) The ternary bismuth(II) chalcogenometallates(III) Bi₂M₄X₈ (with M = Al, Ga and X = S, Se) were synthesized from the binary chalcogenides M₂X₃ and Bi₂X₃ and elementary bismuth. All compounds are diamagnetic semiconductors with E_g (opt.) = 1.8–2.7 eV. The phases (except Bi₂Al₄Se₈) are thermodynamically stable and decompose peritectically above 965–1020 K. Bi₂Al₄Se₈ is metastable below 825 K and is obtained only by rapid quenching from T > 825 K. The isotypic compounds crystallize in a new tetragonal tP28 structure type (P4/nnc). The characteristic unit is the hitherto unknown clustercation Bi₂⁴⁺, with the mean bond length d(Bi–Bi) = 314.2 pm, the Raman frequency 102 cm^–1 ≤ ν_s ≤ 108 cm^–1, and the mean force constant of f = 0.68 N · cm^–1. The Electron Localization Function, ELF, shows the covalent Bi–Bi bond, the lone electron pairs of the ψ-octahedrally coordinated Bi(II) cations, and the polar character of the Bi–X bonds.     

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 Rheniumkomplexe mit Trichalkogenido- und Tetrachalkogenido-Chelatliganden

New Rhenium Complexes Containing Trichalcogenido and Tetrachalcogenido Chelate Ligands The reactions of Cp*ReCl₄ with polychalcogenide salts such as Na₂S₄ or (NEt₄)₂Se₆ lead initially to the violet trichalcogenido chelate complexes Cp*ReCl₂(E₃) (E = S ( 3a ), Se ( 3b )) which, due to their functional chloro ligands, can be used as intermediates for further reactions. Upon hydrolysis in moist solvents or aminolysis with tert. butylamine 3a, b are converted into the tetrachalcogenido chelate complexes Cp*Re(O)(E₄) (E = S ( 4a ), Se ( 4b )) and Cp*Re(N^tBu)(E₄) (E = S ( 5a ), Se ( 5b )), respectively. X-Ray structure analyses were carried out for the three mononuclear cyclo-oligoselenido compounds 3b–5b . It appears that the size of the Se^2?_n chelate ring (n = 3 or 4) essentially depends on steric factors within the coordination sphere of rhenium.     

Synthese,Struktur und Eigenschaften von [(C4H9)2NH2]4[Sn2Se6], [(C4H9)2NH2]4[Sn4Se10] · 2 H2O und [(C3H7)3NH]2[Sn3Se7]

About Selenidostannates. I Synthesis, Structure, and Properties of [Sn₂Se₆]^4–, [Sn₄Se₁₀]^4–, and [Sn₃Se₇]^2– The selenidostannates [(C₄H₉)₂NH₂]₄Sn₂Se₆ · H₂O ( I ), [(C₄H₉)₂NH₂]₄Sn₄Se₁₀ · 2 H₂O ( II ) und [(C₃H₇)₃NH]₂Sn₃Se₇ ( III ) were prepared by hydrothermal syntheses from the elements and the amines. I crystallizes in the monoclinic spacegroup P2₁/n (a = 1262.9(3) pm, b = 1851.3(4) pm, c = 2305.2(4) pm, β = 104.13(3)° and Z = 4). The [Sn₂Se₆]^4– anion consists of two edge‐sharing tetrahedra. II crystallizes in the orthorhombic spacegroup Pna2₁ (a = 2080.3(4) pm, b = 1308.2(3) pm, c = 2263.5(5) pm and Z = 4). The anion is formed from four SnSe₄ tetrahedra which are joined by common corners to the adamantane cage [Sn₄Se₁₀]^4–. III crystallizes in the orthorhombic spacegroup Pbcn (a = 1371.1(3) pm, b = 2285.4(5) pm, c = 2194.7(4) pm and Z = 8). The anion is a chain, built from edge‐sharing [Sn₃Se₅Se_4/2]^2– units, in which two corner sharing tetrahedra are connected to a trigonal bipyramid by an edge of one and a corner of the other tetrahedron. The results of the TG/DSC measurements and of temperature dependent X‐ray diffractograms reveal that I and II decompose at first by release of minor quantities of triethylammonium to compounds with layer structure and larger cell dimensions. At still higher temperature the rest of triethylammonium and H₂Se is evolved, leaving SnSe₂ and Se in the bulk. The former decomposes partially at the highest temperature to SnSe. In the measurements of III the complex intermediate compound was not observed. III decomposes directly to SnSe₂.     

(PPh4)2[(SN)ReCl3(μ‐N)(μ‐NSN)ReCl3(THF)] – ein Nitrido‐Thionitrosyl‐Dinitridosulfato‐Komplex des Rheniums

(PPh₄)₂[(SN)ReCl₃(μ‐N)(μ‐NSN)ReCl₃(THF)] – a Nitrido‐Thionitrosyl‐Dinitridosulfato‐Complex of Rhenium The title compound has been prepared from PPh₄[Re^VIICl₄(NSCl)₂] with excess N(SiMe₃)₃ in dichloromethane solution to give red‐brown single crystals after recrystallisation from acetonitrile/THF solutions. As a by‐product PPh₄[ReNCl₄] is formed. (PPh₄)₂[(SN)ReCl₃(μ‐N)(μ‐NSN)ReCl₃(THF)] ( 1 ): Space group P2₁/n, Z = 4, lattice dimensions at –80 °C: a = 1024.1(1), b = 2350.2(1), c = 2315.4(2) pm, β = 94.09(1)°, R₁ = 0.0403. In the complex anion of 1 the rhenium atoms are connected by an asymmetric Re≡N–Re bridge as well as by a (NSN)^4–‐bridge to form a planar Re₂N(NSN) six‐membered heterocycle. Both rhenium atoms are coordinated by three chlorine atoms, one of them by a thionitrosyl ligand, the other one by the oxygen atom of a thf molecule.     

Die Orientierung der Re2Cl82–‐Ionen in (PPh4)2[Re2Cl8] · 2 L (L = Acetonitril,Dichlormethan)

The Orientation of the Re₂Cl₈^2– Ions in (PPh₄)₂[Re₂Cl₈] · 2 L (L = Acetonitrile, Dichloromethane) (PPh₄)₂[Re₂Cl₈] · 2 MeCN was obtained in small yields from PPh₄Cl and ReCl₅ in the presence of Na₂S₄ or K₂S₅ in acetontrile. Its crystal structure was determined by X‐ray diffraction. The crystals are nearly isotypic with those of (PPh₄)₂[Re₂Cl₈] · 2 CH₂Cl₂. The PPh₄⁺ ions, the solvent molecules, and the chlorine atoms occupy nearly identical positions in both triclinic structures. Nevertheless, 98% of the Re≡Re groups are differently oriented within the slightly elongated Cl₈ cubes surrounding them. The space requirement of the elongated cubes seems to be more important for the orientation than electrostatic forces. The PPh₄⁺ ions form (PPh₄⁺)₂ pairs around inversion centers.     

[Ga(en)3][Ga3Se7(en)] · H2O: Ein Galliumchalkogenid mit Ketten aus [Ga3Se6Se2/2(en)]3–-Bicyclen

[Ga(en)₃][Ga₃Se₇(en)] · H₂O: A Gallium Chalcogenide with Chains of [Ga₃Se₆Se_2/2(en)]^3– Bicycles The new selenidogallate [Ga(en)₃][Ga₃Se₇(en)] · H₂O ( I ) was produced from a ethylendiamine suspension of Ga and Se at 130 °C. I crystallizes in the orthorhombic space group Pna2₁ with unit constants a = 1347.9(3) pm, b = 961.6(1) pm, c = 1967.6(4) pm and Z = 4. The crystal structure contains an anion so far not observed in gallium chalcogenides. It is built from [Ga₃Se₆Se_2/2(en)]^3– bicycles of three Ga^IIIL₄ tetrahedra (L = en, Se) connected via selenium corners to linear chains. The cations, Ga^III ions coordinated by three ethylendiamine in a distorted octahedral geometry are positioned in the holes of the hexagonal rod packing of these chains.     

KCuMIVF7 (MIV = Zr4+, Hf 4+), ein neuer Strukturtyp

KCuM^IVF₇ (M^IV = Zr⁴⁺, Hf ⁴⁺) a New Type of Structure KCuZrF₆ (colourless, orthorhombic, Cmcm – D (No. 63); a = 829,6 pm, b = 1276,5 pm, c = 1011,6 pm, Z = 8) and KCuHfF₇ (colourless, orthorhombic, Cmcm – D (Nr. 63); a = 829,6 pm, b = 1276,5 pm, c = 1011,6 pm, Z = 8) could be prepared by heating up in a goldtube at 700 °C for 3 weeks a mixture of KF, CuF₂, and ZrF₄ or HfF₄, respectively. Both compounds crystallize isotypic in a previous unknown structure.     

[Rb2(H2O)2][Re3(μ-Cl)3Br7(H2O)2]2 · H2O,ein gemischtes Halogenid-Hydrat mit anionischen Dimeren {[Re3(μ-Cl)3Br7(H2O)2]2 · H2O}2−

[Rb₂(H₂O)₂][Re₃(μ-Cl)₃Br₇(H₂O)₂]₂ · H₂O, a Mixed Halide-Hydrate with the Anionic Dimer {[Re₃(μ-Cl)₃Br₇(H₂O)₂]₂ · H₂O}^2? [Rb₂(H₂O)₂][Re₃(μ-Cl)₃Br₇(H₂O)₂]₂ · H₂O crystallizes as dark redbrown single crystals from an hydrobromic-acid solution of ReCl₃ and RbBr at 0°C. An important feature of the crystal structure (monoclinic, C2/c; a = 1494.61(8); b = 835.71(4); c = 3079.96(19) pm; β = 97.801(4)°; V_m = 573.9(4) cm³mol^?1; R = 0.060; R_w = 0.038) is the connection of two anions [Re₃(μ-Cl)₃Br₇(H₂O)₂]^? via a water molecule to dimers, {[Re₃(μ-Cl)₃Br₇(H₂O)₂]₂ · H₂O}^2?. These dimeric units are contained in slabs that are stacked in the [001] direction and held together by Rb⁺ cations and crystal water.     

[(C2H5)3NH]2Sn3Se7 · 0,25 H2O und [(C3H7)2NH2]4Sn4Se10 · 4 H2O

Synthesis, Structure, and Properties of Some Selenidostannates. II. [(C₂H₅)₃NH]₂Sn₃Se₇ · 0,25 H₂O and [(C₃H₇)₂NH₂]₄Sn₄Se₁₀ · 4 H₂O The new selenidostannate hydrates [(C₂H₅)₃NH]₂Sn₃Se₇ · 0.25 H₂O ( I ) and [(C₃H₇)₂NH₂]₄Sn₄Se₁₀ · 4 H₂O ( II ) were synthesized from an aqueous suspension of triethylammonium (tripropylammonium), tin, selenium I and in addition sulfur II at 130 °C. I crystallizes at ambient temperature in the monoclinic space group P2₁/n (a = 2069,3(4) pm, b = 1396,6(3) pm, c = 2342,8(5) pm, β = 114,68(3)°, Z = 8) and is characterized by two different anions, chains from edge‐sharing [Se₃Se₇]^2– units and nets from trigonal SnSe₅ bipyramids. II crystallizes at ambient temperature in the tetragonal space group I4₁/amd (a = 2150,0(3) pm, c = 1174,4(2) pm, Z = 4) and contains adamantane like [Sn₄Se₁₀]^4–‐cages. The UV‐VIS spectra of the selenidostannates demonstrate that the absorption edges red shift as the dimensionality of the compounds is increased.     

Zur Darstellung phosphido‐chalkogenido‐verbrückter Dirheniumkomplexe vom Typ Re2(μ‐PCy2)(μ‐ER)(CO)8 (E = S,Se, Te; R = org. Rest)

Synthesis of Phosphido Chalcogenido Bridged Dirhenium Complexes of the Type Re₂(μ‐PCy₂)(μ‐ER)(CO)₈ (E = S, Se, Te; R = org. Residue) The reaction of Re₂(μ‐Br)(μ‐PCy₂)(CO)₈ with nucleophiles MER (M = Na, Li; E = S, Se, Te; R = org. residue) gives via substitution of the bromido bridge phosphido chalcogenido bridged dirhenium complexes of the general formula Re₂(μ‐PCy₂)(μ‐ER)(CO)₈. The new compounds were characterized by IR, ¹H and ¹³C NMR spectroscopic data and by elemental analyses. In addition the molecular structures for E = S, Se, Te and R = Ph as well as for E = S and R = H, n‐Bu, 2‐pyridyl have been established by single crystal X‐ray analysis. ¹³C NMR spectra of Re₂(μ‐PCy₂)(μ‐EPh)(CO)₈ (E = S, Se, Te) prove that the sulfur and selenium compounds are at room temperature dynamic molecules due to inversion of the pyramidal chalcogenido bridge. The tellurium compound, however, is rigid on the time scale of ¹³C NMR spectroscopy. Eventually the reactivity of the SH function of the novel complex Re₂(μ‐PCy₂)(μ‐SH)(CO)₈ was investigated by reaction with Re₂(CO)₈(MeCN)₂. In toluene at 90 °C the novel spirocyclic complex Re₂(μ‐PCy₂)(CO)₈(μ₄‐S)Re₂(μ‐H)(CO)₈ was formed by SH oxidative addition.     

Die neuen gemischtvalenten Chalkogenoindate MIn7X9 (M = Rb,Cs; X = S,Se): Strukturchemie,Röntgenund HRTEM‐Untersuchungen

The New Mixed Valent Chalcogenoindates MIn₇X₉ (M = Rb, Cs; X = S, Se): Structural Chemistry, X‐Ray and HRTEM Investigations Systematic X‐ray and HRTEM investigations on the ternary systems alkali metal (or thallium)–indium–chalcogen proved the existence of mixed valent solids with the simultaneous occurrence of indium species in different states of oxidation. Additionally to the earlier described solids MIn₅S₇ (M: Na, K, Tl: isotypic to InIn₅S₇ = In₆S₇ and TlIn₅S₇) and KIn₅S₆ (isotyp to TlIn₅S₆) in the actual work we present with MIn₇X₉ (M: Rb, Cs; X: S, Se) a new structure type which also contains indium in the states of oxidation +3 and +2. The formal state of oxidation In²⁺ corresponds to (In₂)⁴⁺ ions. A reasonable ionic formulation of these structures is given by: MIn₅S₇ = M⁺ 3[In³⁺] [(In₂)⁴⁺] 7[S^2–] (M = Na, K, Tl), MIn₅S₆ = M⁺ [In³⁺] 2[(In₂)⁴⁺] 6[S^2–] (M = K, Tl), MIn₇X₉ = M⁺ 3[In³⁺] 2[(In₂)⁴⁺] 9[S^2–]. The three structure types show common two dimensional structure elements which contain ethane analogous In₂X₆ units and cis and trans edge sharing double octahedron chains. The main interest of this work is a crystalchemical discussion taking into account the new compounds MIn₇X₉ and the results of special HRTEM investigations on MIn₇X₉. The HRTEM investigations aim on the identification and subsequent preparation of new phases which initially might be visible as nano size crystals or inclusions in the HRTEM only.     

Halogenaustausch an Re3-Clustern: Ein neuer Syntheseweg für binäre und ternäre Rhenium(III)-bromide. Kristallstrukturen von Cs2[Re3Br11] und Cs3[Re3Br3Cl9]

Halogen Exchange at Re₃-Clusters: A New Synthetic Route to Binary and Ternary Rhenium(III) Bromides. Crystal Structures of Cs₂[Re₃Br₁₁] and Cs₃[Re₃Br₃Cl₉] The substitution of “inner” ligands in transition metal clusters in aqueous HX solutions is hitherto unknown. For the first time the substitution of bridging and terminal chloride for bromide ions was observed at rhenium clusters, [Re₃(μ-Cl^i,b)₃(Cl)(Cl^i,t)_(3?x)(H₂O^i,t)_x]^(3?x)? (x = 0–3), via the reaction of “ReCl₃ · 2 H₂O” in hot hydrobromic acid solution under an inert gas atmosphere. This establishes a new synthetic route to ternary Re(III) bromides as well as to ReBr₃. However, ternary Re(IV) bromides, A₂ReBr₆ (A = Rb, Cs), are dominating in the presence of oxygen, rhenium(III) bromides are only by-products. Dark brown rods of Cs₂[Re₃Br₁₁] are obtained from argon saturated, hot hydrobromic acid solutions of “ReCl₃ · 2 H₂O” and CsBr. The crystal structure (orthorhombic, Pnma (Nr. 62); a = 955.51(5); b = 1 610.29(10); c = 1 372.70(9); Z = 4; V_m = 318.0(2) cm³mol^?1; R = 0.084, R_w = 0.058) consists of defect clusters [Re₃BrBrBr□^i,t]^2? in which one in plane, terminal position is not occupied. The substitution of “inner” ligands has been observed in the case of chloride for bromide only, the Br^i,b and I^i,b ligands in ReBr₃ and ReI₃, respectively, are not substituted in hydrochloric acid even at temperatures as high as 100°C. Bordeaux red square pyramids of CsReBrCl₃ = Cs₃[Re₃(μ-Br^i,b)₃ClCl] are obtained from hot hydrochloric acid solutions of ReBr₃ · 2/3 H₂O upon evaporation. CsReBrCl₃ (orthorhombic, C2cm (Nr. 40); a = 1 419.0(1); b = 1 419.2(1); c = 1 080.30(8) pm; Z = 4; V_m = 327.6(3) cm³mol^?1; R = 0.033, R_w = 0.028) is isostructural to the corresponding chloride CsReCl₄.     

Darstellung,Kristallstruktur und IR‐Spektren von BeSeO3 · H2O – Wasserstoffbrücken und Korrelation von IR‐ und Strukturdaten in den Monohydraten MSeO3 · H2O (M = Be,Ca, Mn,Co, Ni,Zn, Cd)

Preparation, Crystal Structure and IR Spectra of BeSeO₃ · H₂O – Hydrogen Bonds and Correlation of IR and Structure Data in the Monohydrates MSeO₃ · H₂O (M = Be, Ca, Mn, Co, Ni, Zn, Cd) BeSeO₃ · H₂O (oP32) has been obtained by treating amorphous BeSeO₃ · 4 H₂O precipitated from Be(HSeO₃)₂ solutions hydrothermally at 150 °C. The crystal structure (P2₁2₁2₁, a = 560.59(4), b = 755.25(5), c = 781.14(5) pm, Z = 4, D_X = 3.092 gcm^–3, R = 0.018 for the 2034 reflections with I > 2σ_I of the enantiomer investigated) contains BeO₃(H₂O) tetrahedra built up from three selenite and one water oxygen atoms. The BeO₃(H₂O) tetrahedra are 3 D‐connected via Se atoms of trigonal pyramidal SeO₃^2– ions. The Be–O distances are 161.8 to 164.4 pm. The Se–O bond lenghts (169.2–170.3 pm) and the O–Se–O bond angles (98.1–101.4°) are normal. The water molecules of crystallization form together with the SeO₃^2– ions screw‐like hydrogen bond systems along [100]. Despite the strong synergetic effect of the Be²⁺ ions, the hydrogen bonds (d(OH…O) = 267.4 and 276.4 pm, respectively; ν_OD of matrix isolated HDO molecules: 2244 and 2405 cm^–1, respectively) are normal compared to other neutral selenite hydrates. Together with the hitherto known monohydrates M^IISeO₃ · H₂O and other beryllium salt hydrates, the hydrogen bonds of BeSeO₃ · H₂O are discussed with regard to their geometry and IR spectroscopy.     

Rheniumselenidtelluride Re2SexTe5–x: Die Struktur von Re6Se8Te7

Rhenium Selenidetellurides Re₂Se_xTe_5–x: The Structure of Re₆Se₈Te₇ Well-crystallized rhenium selenidetellurides of the Re₂Te₅-type structure were prepared from the elements in evacuated sealed quartz glas tubes at 1 130 K within 14 d. The orthorhombic lattice parameters of the phases shrink with increasing selenium content from a = 1 304.9(1) ? 1 255.8(2) pm, b = 1 297.5(1) ? 1 260.0(2) pm, and c = 1 425.1(1) ? 1 408.2(1) pm. The phase width ends at composition Re₂Se_2.7Te_2.3. An X-ray structure analysis of a crystal of composition Re₆Se₈Te₇ was performed. Selenium and tellurium atoms differ structurally completely: Whereas the selenium atoms are separated within distorted octahedral [Re₆Se₈] clusters, the tellurium atoms form homonuclear bonded bicyclic [Te(Te₃)₂] units. They also link the clusters which are arranged according to the motif of a cubic closest packing.     

Zr7(Sb,Se)4 – eine polare Variante des Nb7P4-Strukturtyps

Zr₇(Sb,Se)₄ – a Polar Variant of the Nb₇P₄ Structure Type Single crystals of Zr₇Sb_1.6(1)Se_2,4 were obtained by arc-melting of compressed mixtures of Zr, ZrSb₂, and ZrSe₂, followed by annealing at 1300 °C in an induction furnace using traces of iodine to promote crystal growth. The crystal structure (a = 375.98(4), b = 1662.6(2), c = 1476.7(2) pm, V = 923.1(2) 10⁶ pm³, Cmc2₁, Z = 4) was determined by single crystal X-ray means. Zr₇Sb_1.6(1)Se_2.4 forms a unique polar structure composed of condensed tri-capped trigonal prismatic Zr₉ clusters, being stabilized by interstitial Sb/Se atoms. The remaining Sb and Se atoms reside in mono- and bi-capped trigonal prismatic Zr₇ and Zr₈ clusters, respectively, of the extended cluster network. Characteristic structural distinctions and relations between Zr₇(Sb,Se)₄ and congeneric Zr₇P₄ are highlighted.     

Chelatkomplexe von Rheniumtetrachlorid. Die Kristallstrukturen von ReCl4(DME) und ReCl4(DPPE) · Tolan

Chelate Complexes of Rhenium Tetrachloride. The Crystal Structures of ReCl₄(DME) and ReCl₄(DPPE) · Tolan Bright green crystals of ReCl₄(DME) have been prepared by the reaction of rhenium pentachloride with dimethoxyethane (DME) in dichloromethane. ReCl₄(DPPE) · tolan was obtained in form of red crystals by the reaction of the alkyne complex [ReCl₄(Ph? C?C? Ph)(POCl₃)] with bis(diphenylphosphino)ethane (DPPE) in dichloromethane. The complexes were characterized by X-ray structure determinations. ReCl₄(DME): Space group I4 2d, Z = 8, 829 observed unique reflexions, R = 0.022. Lattice dimensions at 19.5°C: a = b = 960.60(6), c = 2337.2(6) pm. The complex forms monomeric molecules with DME as chelating ligand; the Re? O bond lengths are 213.1 pm. The chlorine atoms, arranged in trans position to the chelating ligand, have slightly shorter Re? Cl bonds than the chlorine atoms in cis position (232,1 pm). ReCl₄(DPPE) · tolan: Space group P2₁/n, Z = 4,4313 observed unique reflexions, R = 0.040. Lattice dimensions at ?80°C: a = 1095.7(1), b = 1764.2(2), c = 1898.0(2) pm, β = 99.229(8)°. The compound consists in form of monomeric molecules [ReCl₄(DPPE)] and diphenylacetylene molecules, which are incorporated in the lattice. The two phenyl rings of the tolan molecules are twisted towards each other along the C? C axis with a dihedral angle of 21°. The DPPE molecules are bonded to the rhenium atom in a chelating fashion with medium Re? P lengths of 250.4 pm. The chlorine atoms, arranged in trans position to this ligand, with Re? Cl bond lengths of 234.5 pm are slightly longer than the Re? Cl bonds in cis position with 232.3 pm.     

Die Kristallstrukturen von (NH4)2[ReCl6], [ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN und [ReCl4(18-Krone-6)]

The Crystal Structures of (NH₄)₂[ReCl₆], [ReCl₂(CH₃CN)₄]₂[ReCl₆] · 2CH₃CN and [ReCl₄(18)(Crown-6)] Brown single crystals of (NH₄)₂[ReCl₆] are formed by the reaction of NH₄Cl with ReCl₅ in a suspension of diethylether. [ReCl₂(CH₃CN)₄]₂[ReCl₆] · 2CH₃CN crystallizes as brown crystal plates from a solution of ReCl₅ in acetonitrile. Lustrous green single crystals of [ReCl₄(18-crown-6)] are obtained by the reaction of 18-crown-6 with ReCl₅ in a dichloromethane suspension. All rhenium compounds are characterized by IR spectroscopy and by crystal structure determinations. (NH₄)₂[ReCl₆]: Space group Fm3 m, Z = 4, 75 observed unique reflections, R = 0.01. Lattice constant at ?70°C: a = 989.0(1) pm. The compound crystallizes in the (NH₄)₂[PtCl₆] type, the Re? Cl distance is 235.5(1) pm. [ReCl₂(CH₃CN)₄]₂[ReCl₆] · 2CH₃CN: Space group P1, Z = 1, 2459 observed unique reflections, R = 0.12. Lattice dimensions at ?60°C: a = 859.0(1), b = 974.2(7), c = 1287.3(7) pm, α = 102.69(5)°, b? = 105.24(7)°, γ = 102.25(8)°. The structure consists of two symmetry-independent [ReCl₂(CH₃CN)₄]⁺ ions with trans chlorine atoms, [ReCl₆]^2? ions, and included acetonitrile molecules. In the cations the Re? Cl bond lengths are 233 pm in average, in the anion they are 235 pm in average. [ReCl₄(18-crown-6)]: Space group P2₁/n, Z = 4, 3 633 observed unique reflections, R = 0.06. Lattice dimensions at ?70°C: a = 1040.2(4), b = 1794.7(5), c = 1090.0(5) pm, b? = 108.91(4)°. The compound forms a molecular structure, in which the rhenium atom is octahedrally coordinated by the four chlorine atoms and by two oxygen atoms of the crown ether molecule.