Reaction of trimethylaluminum with crown ethers. II. The synthesis and crystal structure of (Dibenzo-18-crown-6)tris(trimethylaluminum) and of (18-crown-6)tetrakis(trimethylaluminum)

Both title compounds were prepared by adding AlMe₃ to a suspension of the appropriate crown ether in toluene, followed by reaction in a sealed tube. Both products were obtained in the form of extremely air-sensitive, colorless crystals. [AlMe₃]₃[dibenzo-18-crown-6] crystallizes in space group Pī, witha=8.898(4),b=11.848(5),c=19.060(6) Å, α=74.86(3), β=80.73(4), and γ=67.02(4)°. Refinement led to a final conventional weightedR value of 0.052 for 1800 reflections. [AlMe₃]₄[18-crown-6] belongs to space group Pbcn, witha=18.753(3),b=12.570(6), andc=15.095(6) Å. Refinement was taken toR _w =0.064 for 1320 reflections.     

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.     

Kronenetherkomplexe von Blei(II). Die Kristallstrukturen von [PbCl(18-Krone-6)][SbCl6], [Pb(18-Krone-6)(CH3CN)3][SbCl6]2, and [Pb(15-Krone-5)2][SbCl6]2

Crown Ether Complexes of Lead(II). The Crystal Structures of [PbCl(18-Krone-6)][SbCl₆], [Pb(18-Krone-6)(CH₃CN)₃][SbCl₆]₂ und [Pb(15-Krone-5)₂][SbCl₆]₂ . [PbCl(18-crown-6)][SbCl₆] has been prepared in low yield besides [Pb(CH₃)₂(18-crown-6)][SbCl₆]₂ by the reaction of Pb(CH₃)₂Cl₂ with antimony pentachloride in acetonitrile solution in the presence of 18-crown-6, forming pale-yellow crystals. The other two title compounds are formed as colourless crystals by the reaction of PbCl₂ with antimony pentachloride in acetonitrile solutions in the presence of 18-crown-6 and 15-crown-5, respectively. The complexes were characterized by IR spectroscopy and by crystal structure determinations. [PbCl(18-crown-6)][SbCl₆]: Space group P2₁/c, Z = 8, 5 003 observed unique reflections, R = 0.046. Lattice dimensions at - 80°C: a = 1 386.9; b = 1 642.7; c = 2 172.1 pm, β = 92.95°. The lead atom in the cation [PbCl(18-crown-6)]⁺ is surrounded in an almost hexagonal-planar construction by the six oxygen atoms of the crown ether and an axially oriented Cl atom. [Pb(18-crown-6)(CH₃CN)₃][SbCl₆]₂: Space group P1 , Z = 2, 6 128 observed unique reflections, R = 0.076. Lattice dimensions at - 70°C: a = 1 228.0; b = 1 422.9; c = 1 463.2 pm, α = 69.08°; β = 65.71°; γ = 64.51°. In the cation [Pb(18-crown-6)(CH₃CN)₃]²⁺ the lead atom is coordinated by the six oxygen atoms of the crown ether and by the three nitrogen atoms of the acetonitrile molecules. The structure determination is restricted by disorder. [Pb( 15-crown-5)₂][SbCI₆]₂: Space group P6₃/m, Z = 6, 5 857 observed unique reflections, R = 0.059. Lattice dimensions at -70°C: a = b = 2 198.5; c = 1499.4 pm, α = β = 90°, γ = 120°. In the cation [Pb(l5-crown-5)₂]² the lead atom is sandwich-like coordinated by the ten oxygen atoms of the two crown ether molecules. The structure determination is restricted by disorder.     

Complex Formation of Potassium Hexachloroplatinate with 18-Crown-6 and Dibenzo-18-Crown-6 in Acetonitrile

The products of the reactions between potassium hexachloroplatinate {K₂PtCl₆} and 18-crown-6 or dibenzo-18-crown-6 in acetonitrile were studied. Pure crystalline compounds [2K·2(18-crown-6)· 2CH₃CN]²⁺·[PtCl₆]^2-·2H₂O, [2K·dibenzo-18-crown-6·CH₃CN]^{2 +}·[PtCl₆]^{2 -}, and [2K·dibenzo-18-crown-6·CH₃CN]^{2 +}·[Pt₂Cl₁₀]^{2 -} were obtained. Physicochemical properties of these compounds were studied, and their near- and far-IR IR spectra and thermogravimetric curves were considered. The composition of the complexes is determined by metal:ligand molar ratio and crown ether nature. It was found that acetonitrile is coordinated via the nitrogen atom.     

Darstellung und Kristallstruktur der Addukte [DB-18C6] · CH3CN · CH3CSOH und [DC-18C6](CH3CSOH)2 sowie der salzartigen Verbindungen [Cs(B-15C5)2]CH3CSS und [Cs(DB-18C6)]2S5(DMF)21)

Synthesis and Crystal Structure of the Adducts [DB-18C6] · CH₃CN · CH₃CSOH and [DC-18C6](CH₃CSOH)₂ as well as of the Salt-like Compounds [Cs(B-15C5)₂]CH₃CSS and [Cs(DB-18C6)]₂S₅(DMF)₂¹) The reaction products of crown ethers, cesium, and sulfur in aprotic solvents like acetonitrile and dimethylformamide strongly depend on the reaction conditions. Using CH₃CN as a solvent, sometimes neutral host-guest adducts crystallize only, e.g., [dibenzo-18C6] · CH₃CN · CH₃CSOH (monoclinic, S. G. P2₁/c, Z = 4, a = 9.73(1) Å, b = 22.03(1) Å, c = 11.86(1) Å, β = 91.8(1)°) or [dicyclohexyl-18C6](CH₃CSOH)₂ (monoclinic, S. G. P2₁/n, Z = 2, a = 7.75(1) Å, b = 10.32(1) Å, c = 17.73(1) Å, β = 95.7(1)°). The monothioacetic acid, CH₃CSOH, must be regarded as the first product of the hydrolysis of CH₃CN. Furthermore, another product of this kind of hydrolysis, CH₃CSSH, is obtained too. Therefore, we also obtain the salt-like compound [Cs(benzo-15C5)₂]CH₃CSS (monoclinic, S. G. C2/c, Z = 4, a = 16.05(1) Å, b = 16.73(1) Å, c = 13.11(1) Å, β = 106.3(1)°). If the solvent DMF is used, the pentasulfide [Cs(dibenzo-18C6)]₂S₅(DMF)₂ crystallizes (monoclinic, S. G. P2₁/n, Z = 4, a = 14.79(1) Å, b = 14.24(1) Å, c = 25.74(1) Å, β = 92.7(1°. The S₅^2? anions show the cis-conformation.     

Die Kristallstrukturen der Hexachlorometallate NH4[SbCl6], NH4[WCl6], [K(18‐Krone‐6)(CH2Cl2)]2[WCl6]·6CH2Cl2 und (PPh4)2[WCl6]·4CH3CN

Crystal Structures of the Hexachlorometalates NH₄[SbCl₆], NH₄[WCl₆], [K(18‐crown‐6)(CH₂Cl₂)]₂[WCl₆]·6CH₂Cl₂ and (PPh₄)₂[WCl₆]·4CH₃CN The crystal structures of the title compounds were determined by single crystal X‐ray methods. NH₄[SbCl₆] and NH₄[WCl₆] crystallize isotypically in the space group C2/c with four formula units per unit cell. The NH₄⁺ ions occupy a twofold crystallographic axis, whereas the metal atoms of the [MCl₆]^— ions occupy a centre of inversion. There exist weak interionic hydrogen bridges. [K(18‐crown‐6)(CH₂Cl₂)]₂[WCl₆]·6CH₂Cl₂ crystallizes in the orthorhombic space group R3¯/m with Z = 3. The compound forms centrosymmetric ion triples, in which the potassium ions are coordinated with a WCl₃ face each. In trans‐position to it the chlorine atom of a CH₂Cl₂ molecule is coordinated so that, together with the oxygen atoms of the crown ether, coordination number 10 is achieved. (PPh₄)₂[WCl₆]·4CH₃CN crystallizes in the monoclinic space group P2₁/c with Z = 4. This compound, too, forms centrosymmetric ion triples, in which in addition the acetonitrile molecules are connected with the [WCl₆]^2— ion via weak C—H···Cl contacts.     

f-Element/crown ether complexes, 11. Preparation and structural characterization of [UO2(OH2)5] [ClO4]2·3(15-crown-5)·CH3CN and [UO2(OH2)5] [ClO4]2·2(18-crown-6)·2 CH3CN·H2O

The reaction of UO₂(ClO₄)·nH₂O with 15-crown-5 and 18-crown-6 in acetonitrile yielded the title complexes. [UO₂(OH₂)₅] [ClO₄]₂·3(15-crown-5)·CH₃CN crystallizes in the triclinic space groupPT with (at–150°C)a=8.288(6),b=12.874(7),c=24.678(7) Å, =82.62(4), =76.06(5), =81.06(5)°, andD _calc=1.67 g cm^–3 forZ=2 formula units. Least-squares refinement using 6248 independent observed reflections [F _o5(F _o)] led toR=0.111. [UO₂(OH₂)₅] [ClO₄]₂·2(18-crown-6)·2CH₃CN·H₂O is orthorhombicP2₁2₁2₁ with (at–150 °C)a=12.280(2),b=17.311(7),c=22.056(3) Å,D _calc=1.68 g cm^–3,Z=4, andR=0.032 (3777 observed reflections). In each complex the crown ether molecules are hydrogen bonded to the water molecules of the pentagonal bipyramidal [UO₂(OH₂)₅]²⁺ ions, each crown ether having exclusive use of two hydrogen atoms from one water molecule and one hydrogen from another water molecule. In the 15-crown-5 complex the remaining hydrogen bonding interaction is between one of the water molecules and one of the perchlorate anions. The solvent molecule has a close contact between the methyl group and a perchlorate anion suggesting a weak interaction. There are a total of three U-OH...OClO₃ hydrogen bonds to the two perchlorate anions in [UO₂(OH₂)₅] [ClO₄]₂·(18-crown-6)·2CH₃CN ·H₂O. The remaining coordinated water hydrogen bond is to the uncoordinated 2H₂O molecule, which in turn is hydrogen bonded to a perchlorate oxygen atom and an acetonitrile nitrogen atom. One solvent methyl group interacts with an anion, the other with one of the 18-crown-6 molecules. Unlike the 15-crown-5 structure, the hydrogen bonding in this complex results in a polymeric network with formula units joined by hydrogen bonds from one of the solvent molecules and the uncoordinated water molecule. Supplementary data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82051 (37 pages).For Part 10, see reference [1].     

Tetrakis(isothiocyanato)manganese(II) bis[aqua(18-crown-6)potassium] (18-crown-6)(thiocyanato)potassium

A new complex compound, i.e., tetrakis(isothiocyanato)manganese(II) bis[aqua(18-crown-6)potassium] (18-crown-6)(thiocyanato)potassium, was synthesized and its crystal structure was studied by X-ray diffraction (space group P2₁/m, a = 13.377, b = 14.690, c = 17.499 Å, β = 108.96°, Z = 2) and refined by the least-squares method in anisotropic approximation to R = 0.060 for 4715 independent reflections (CAD-4 automated diffractometer, λMoK _α). In the crystal, infinite chains are formed through the coordination bonds between its components. The monomer fragment of a chain [Mn(NCS)₅K₃(18-crown-6)₃(H₂O)₂] lies in plane m; three of the five SCN^? ligands and one of the two water molecules behave as bridges. The [Mn(NCS)₄]^2? anion has the tetrahedral structure. The coordination polyhedron of each of the three K⁺ cations is a distorted hexagonal bipyramid with six O atom of the corresponding crown ligand in a base. Three 18-crown-6 ligands have standard crown conformation.     

The use of crown ethers to access new M[Al2R6X] species. Synthesis and crystal structure of [K · dibenzo-18-crown-6] [Al2Me6Cl] · 2 C6H6

Potassium chloride does not react with trimethylaluminium in benzene in the absence of a crown ether. With the addition of dibenzo-18-crown-6, a normal liquid clathrate ensues. The composition of the parent compound has been established by a single crystal X-ray diffraction study. The space group is monoclinicP2₁/c with unit cell dimensionsa=21.319(8),b=9.512(4),c=21.081(8) Å, β=93.79(3)°, andρ _calc1.15 g cm^?3 forZ=4. Refinement led to a final conventionalR value of 0.049 for 2224 observed reflections. The anion has the expected angular geometry (Al?Cl?Al=120.0(1)°). There are two different types of benzene in the crystalline solid. One is associated with the K⁺ ion, while the other exists in layers normal to thea axis.     

Diaquabromo(18-crown-6)rubidium and triaqua(18-crown-6)barium dibromide monohydrate: Synthesis and crystal structures

Two complexes are synthesized: diaquabromo(18-crown-6)rubidium [RbBr(18-crown-6)(H₂O)₂] (I) and triaqua(18-crown-6)barium dibromide monohydrate [Ba(18-crown-6)(H₂O)₃]²⁺ 2Br^? · H₂O (II). The orthorhombic structure of compound I (space group Pnma, a = 10.124 Å, b = 15.205 Å, c = 12.544 Å, Z = 4) and the monoclinic structure of compound II (space group C 2/c, a = 17.910 Å, b = 10.315 Å, c = 14.879 Å, β = 123.23°, Z = 4) are determined by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.063 (I) and 0.042 (II) for all 2293 (I) and 3363 (II) independent measured reflections (CAD-4 automated diffractometer, λMoK _α). The complex molecule [RbBr(18-crown-6)(H₂O)₂] in compound I and the randomly disordered cation [Ba(18-crown-6)(H₂O)₃]²⁺ in compound II are of the host-guest type: their Rb⁺ or Ba²⁺ cation (its coordination number is nine) is located in the cavity of the 18-crown-6 ligand and coordinated by all six O atoms. In structure I, the coordination polyhedron of Rb⁺ is a distorted hexagonal pyramid with a triple apex at the Br^? ligand and two O atoms of the water molecules. In structure II, the Ba²⁺ polyhedron is a distorted hexagonal bipyramid with one apex at the O atom of the water molecule and the other split apex at two O atoms of water molecules.     

Über metall-alkyl- und -aryl-verbindungen: XVII. Die kristallstruktur des kaliumhydridotrimethylaluminats,K[AlH(CH3)3]

K[AlH(CH₃)₃] is formed by decomposition of K[Al(CH₃)₃SiH₃] in diethyl ether. The compound crystallizes in the orthorhombic space group Cmca with the lattice parameters a = 9.647, b = 17.332, c = 7.711 Å. There are eight formula units in the unit cell. Analogously to K[Al(CH₃)₄] the hydrido compound contains isolated anions with a tetrahedral coordination of aluminium by hydrogen and three methyl groups.     

Synthesis and structural characterization of acetatobis(triphenylphosphine)dicarbonylmanganese(I), (CH3CO2)Mn(CO)2[P(C6H5)3]2: An organometallic complex containing a chelating acetate ligand

The accidental but intriguing synthesis of acetatobis(triphenylphosphine)dicarbonylmanganese(I), (CH₃CO₂)Mn(CO)₂[P(C₆H₅)₃]₂, has been accomplished by the reaction of NaMn(CO)₅ with (CH₃)₃SiCl followed by the addition of triphenylphosphine and acetic acid. A three-dimensional single-crystal X-ray diffraction analysis has shown an octahedral-like molecule containing a symmetrically oxygen-chelating acetate group, the first such group to be reported in a metal carbonyl complex. The two triphenylphosphine ligands occupy mutually trans positions with the two carbonyl ligands possessing the remaining cis sites in the octahedral complex. The compound crystallizes with four molecules in a monoclinic unit cell of space group symmetry $\text{P}\text{2}{}_1\text{c}$ and of dimensions a = 17.744(2) Å, b = 9.692(1) Å, c = 20.004(2) Å, and β = 106.195(4)°. The relatively long MnO(acetate) bond lengths [2.066(6) and 2.069(7) Å] and the relatively short MnCO bond lengths [1.701(12) and 1.760(13) Å] and the relatively short MnP(C₆H₅)₃ bond lengths [2.260(3) and 2.275(3) Å], compared to the corresponding MnCO and MnP(C₆H₅)₃ bond lengths in other manganese carbonyl triphenylphosphine complexes, are rationalized on the basis that the acetate ligand in this molecule functions primarily as a σ-donor.     

Reaction of trimethylaluminum with a macrocyclic tetradentate tertiary amine. Synthesis and molecular structure of [Al(CH3)3]4[N-tetramethylcyclam]

Reaction of the macrocyclic tetradentate tertiary amine N-tetramethylcyclam with trimethylaluminum produced the crystalline product [Al(CH₃)₃]₄[N-tetramethylcyclam]. The compound crystallizes in the orthorhombic space group Pbca with unit cell parameters a 13.928(5), b 18.522(6), c 1.4538(6) Å, and D_calc 0.96 g cm⁻³ for Z = 4. Least-squares refinement based on 1432 observed reflections led to a final R factor of 0.034, R_w = 0.037. The molecule resides on a crystallographic center of symmetry. The four nitrogen atoms are coplanar. The macrocyclic ligand is greatly distorted as the four Al(CH₃)₃ units have essentially turned it “inside-out” by forcing the nitrogen atoms from the interior cavity to the macrocyclic perimeter. The independent A1-N distances of 2.093)(3) and 2.102(3) Å are among the longest reported.     

Hydrothermal synthesis and structural determination of a three-dimensional microporous iron(III)phosphate: [H3N(CH2)4NH3]3[Fe8(HPO4)12(PO4)2(H2O)6]

A new microporous iron (III) phosphate, [H₃N(CH₂)₄NH₃]₃[Fe₈(HPO₄)₁₂(PO₄)₂(H₂O)₆], has been prepared using low temperature hydrothermal methods and characterized by single-crystal X-ray diffraction, EDAX, infrared spectroscopy, thermogravimetric analysis and bond valence sums. The title compound crystallizes as light pink hexagonal-shaped tabs in the centrosymmetric hexagonal space group 3¯ (No.147) with a = b = 13.495(2) Å, c = 9.396(2) Å, V = 1481.9(4) ų and Z = 4 with R/R_w = 0.044/0.048. The compound exhibits a complicated three-dimensional microporous structure with quaternary ammonium ions acting as a template for the framework. It is similar to previously reported [HN(CH₂CH₂)₃NH]₃[Fe₈(HPO₄)₁₂(PO₄)₂(H₂O)₆].     

Neutral molecule/crown ether interactions 5. Comparison of the C−H acidic interactions of nitromethane and acetonitrile with 18-crown-6 and dibenzo-18-crown-6. Crystal structures of dibenzo-18-crown-6·2 CH3NO2 and dibenzo-18-crown-6·2 CH3CN

Complete structural characterization of dibenzo-18-crown-6·2 CH₃NO₂ and dibenzo-18-crown-6·2 CH₃CN have been carried out, including location and refinement of the methyl hydrogen atoms. Dibenzo-18-crown-6·2 CH₃NO₂ is monoclinic,P2₁/c, with (at –150°C)a=9.573(2),b=14.636(2),c=33.471(7) Å, =93.77(2)°, andD _calc=1.37 g cm^–3 forZ=8. Interactions between the solvent methyl groups and the crown ethers and other solvent nitro groups associate the 1 : 2 complexes into polymeric chains alongb. The acetonitrile adduct exists as discreet 1 : 2 complexes in the solid state with C–H...O interactions exlusively to the ether. This complex is triclinic,P 1, with (at –150°C)a=9.458(6),b=9.570(5),c=14.404(5) Å, =73.18(4), =79.85(5), =66.82(6)°, andD _calc=1.28 g cm^–3 forZ=2. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82070 (22 pages).For part 4, see reference [1].     

Crystal Structure,Phase Transition and Ferroelastic Properties of [N(CH3)4]3[As2Cl9]

The crystal structure of [N(CH₃)₄]₃[As₂Cl₉] is determined at 293 K. It crystallizes in trigonal space group P31c: a = 9.2199(8), c = 21.065(3)Å, Z = 2, R₁ = 0.0505, wR₂ = 0.1283. The crystal is built of the discrete bioctahedral [As₂Cl₉]^3— anions and the deformed tetramethylammonium cations. A structural phase transition in [N(CH₃)₄]₃[As₂Cl₉] is detected by the DSC and dilatometric techniques at 146/151 K (on cooling/heating). Dielectric relaxation studies in the frequency range 75 kHz — 5 MHz indicate reorientations of the tetramethylammonium cations within the high temperature phase. Optical observations show the existence of the ferroelastic domain structure below 146 K. The possible mechanism of phase transition is discussed on the basis of the presented results.     

Crystal structure of tris(ethylenediamine)cobalt(III) (aqua)hexachloromercurate(II) chloride [Co(En)3]2[Hg2(H2O)Cl6]Cl4

The compound [Co(En)₃]₂[Hg₂(H₂O)Cl₆]Cl₄ (I, En is ethylenediamine) has been synthesized and studied by X-ray diffraction. The crystals of I (a = 21.8745(14) Å, b = 10.6008(6) Å, c=15.4465(12) Å, space group Pna2₁) consist of tris(ethylenediamine)cobalt(III) complexes (the unit cell contains two [Co(En)₃]³⁺ cations of opposite chirality). [Hg₂(H₂O)Cl₆]^2? anions, and isolated chloride ions. The complex anion consists of the tetrahedral [HgCl₄]^2? group (Hg-Cl, 2.44–2.56 Å) and the hydrated molecule [Hg(H₂O)Cl₂] (Hg-Cl, 2.301 and 2.308 Å; Hg-O, 2.788 Å) combined by weak Hg-Cl interactions (2.915 and 3.220 Å).     

Molybdänhalogenidcluster mit sechs terminalen Alkoholatliganden: (C18H36N2O6Na)2[Mo6Cl8(OCH3)6] · 6CH3OH und (C18H36N2O6Na2)2[Mo6Cl8(OC6H5)6]

Molybdenum(II) Halide Clusters with six Alcoholate Ligands: (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₈(OCH₃)₆] · 6CH₃OH and (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₈(OC₆H₅)₆] . The reaction of Na₂[Mo₆Cl₈(OCH₃)₆] and 2,2,2-crypt yields (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₈(OCH₃)₆] · 6 CH₃OH ( 1 ), which is converted to (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₈(OC₆H₅)₆] ( 2 ) by metathesis with phenol. According to single crystal structure determinations ( 1 : P3 1c, a=14.613(3) Å, c=21.036(8) Å; 2 : P3 1c, a=15.624(1) Å, c=19.671(2) Å) the compounds contain anionic clusters [Mo₆Cl₈ⁱ(OR^a)₆]^2? ( 1 : d(Mo—Mo) 2.608(1) Å to 2.611(1) Å, d(Mo—Cl) 2.489(1) Å to 2.503(1) Å, d(Mo—O) 2.046(4) Å; 2 : d(Mo—Mo) 2.602(3) Å to 2.608(3) Å, d(Mo—Cl) 2.471(5) Å to 2.4992(5) Å, d(Mo—O) 2.091(14) Å). Electronic interactions of the halide cluster and the phenolate ligands in [Mo₆Cl₈(OC₆H₅)₆]^2? is investigated by means of UV/VIS spectroscopy and EHMO calculations.     

The interaction of aromatic hydrocarbons with organometallic compounds of the main group elements. : IV. The preparation and structure of the novel selenide K[CH3Se{Al(CH3)3}3] · 2C6H6

The crystal structure of K[CH₃Se {Al(CH₃)₃}₃] · 2C₆H₆ has been determined from single-crystal X-ray diffraction data collected by counter methods. The compound crystallizes in the triclinic space group P$\text{1}$ with cell dimensions a = 17.165(7), b = 10.144(7), c = 10.156(7)Å, α = 119.26(5), β = 104.07(5), ψ = 80.51(5)°, and Dc = 1.12 gcm^?3 for Z = 2. Least-squares refinement gave a final R value of 0.083 for 1967 independent observed reflections. One of the two benzene molecules in the asymmetric unit has been located by difference Fourier techniques. Because of either extreme disorder or high thermal motion, the aromatics make practically no contribution to the X-ray scattering. The selenium atom in the anion exhibits tetrahedral coordination. The Al-Se bond lengths average 2.578(5)Å, and the Se-C distance is 1.93(2)Å.     

Die Oxochlorotantalate (PPh4)2[Ta2OCl9]2 · 2 CH2Cl2, (PPh4)2[Ta2OCl10] · 2 CH3CN und (K-18-Krone-6)4[Ta4O6Cl12] · 12 CH2Cl2

The Oxochlorotantalates (PPh₄)₂[Ta₂OCl₉]₂ · 2 CH₂Cl₂, (PPh₄)₂[Ta₂OCl₁₀] · 2 CH₃CN, and (K-18-crown-6)₄[Ta₄O₆Cl₁₂] · 12 CH₂Cl₂ (K-18-crown-6)₄[Ta₄O₆Cl₁₂] · 12 CH₂Cl₂ was obtained from a reaction of tantalum pentachloride, K₂S₅ and 18-crwon-6 in dichlormethane. According to its crystal structure analysis it is tetragonal (space group I 4 2d) and contains [Ta₄O₆Cl₁₂]^4– ions that have an adamantane-like Ta₄O₆ skeleton. Each K⁺ ion is coordinated by the oxygen atoms of the crown ether molecule from one side and with three Cl atoms of one [Ta₄O₆Cl₁₂]^4– ion from the opposite side. (PPh₄)₂[Ta₂OCl₁₀] · 2 CH₃CN was a product from PPh₄Cl and TaCl₅ in acetonitrile in the presence of Na₂S₄. Its crystals are monoclinic (space group P2₁/c) and contain centrosymmetric [Ta₂OCl₁₀]^2– ions having a linear Ta–O–Ta grouping with short bonds (Ta–O 189 pm). TaCl₅ and H₂S formed a solid substance (TaSCl₃) from which a small amount of (PPh₄)₂[Ta₂OCl₉]₂ · 2 CH₂Cl₂ was obtained by the reaction with PPh₄Cl in CH₂Cl₂. The anions in the monoclinic crystals (space group P2₁/n) consist of two Ta₂OCl₉^– units which are joined by chloro bridges; each Ta₂OCl₉^– unit has a nearly linear Ta–O–Ta group with differing bond lengths (179 and 202 pm). The oxygen in the compounds probably was introduced by traces of water in the crown ether, acetonitrile or H₂S, respectively.