Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. 47. Zur Reaktion von Hexachloroceraten(IV) mit Lithiumorganylen

Contributions to the Chemistry of Organo-Transition Metal Compounds. 47. Reactions of Hexachlorocerates(IV) with Organolithium Compounds Pyridinium hexachlorocerate(IV) reacts with lithium organyls RLi RLi (R = 1-Nor, (CH₃)₂NCH₂CH₂CH₂, n-C₄H₉) in the molar ratio 1:2 with formation of Li₂[CeCl₆] · 2 NC₅H₅. A further mol RLi effects a reduction to Li₃[CeCl₆] · 2 NC₅H₅. With an excess of RLi amidocerium(III) complexes of the typ Li₄ are formed. Li₂[CeCl₆] is formed also at reactions of quartery ammonium salts, e. g. [C₆H₅CH₂N(C₂H₅)₃]₂[CeCl₆], with RLi (R = 1-Nor, Me₂₂NCH₂CH₂CH₂) followed by an reduction to Li₃[CeCl₆]. An excess of the lithium organyl effects the formation Li₄[RCeCl₆] complexes. The yielded compounds were characterized by elementary analysis, the hydrolysis and deuterolysis products, magnetic moments, and IR-spectra.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. XLIV. Zur Bildung von Tetraorganylzirconaten(II)

Contributions to the Chemistry of Transition Metall Alkyl Compounds. XLIV. Formation of Tetraorganylzirconates(II) Zirconiumtetraorganyls are reduced by n-butyl lithium with formation of dilithium tetraorganyl zirconates(II). Li₂[Zr(CH₂C₆H₅)₄] and Li₂[Zr(CH₃)₄] were isolated in a definite form as extremely air sensitive compounds, from which a polymer structure can be assumed. The compounds were characterized by elementary analysis, hydrolyses products, reactions with iodine, magnetic moments, and the ESR spectra.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. XLIX. Reaktionen von Cerium(IV)-acetylacetonat mit Lithium- und Magnesiumorganylen

Contributions to the Chemistry of Organo Transition Metal Compounds. XLIX. Reactions of Cerium(IV) Acetylacetonate with Organolithium and Organomagnesium Compounds Reacting Ce(acac)₄ with lithium organyls RLi (R = CH₃ 1-Nor¹), ((CH₃)₂NCH₂CH₂CH₂) in the molar ratio 1:1 the cerium compound is reduced with formation of Li[Ce(acac)₄]. Using a molar ratio of Ce:Li = 1:4 organocerium complexes of the composition R₃Ce · 3 Li(acac) or Li₃[R₃Ce(acac)₃] are formed. From reactions with excess CH₃Li (Ce: Li = 1:7) Li₃[Ce(CH₃)₆] · 3 Li(acac) could be isolated. All cerium complexes are characterized by elementary analysis, hydrolysis products, i.r. spectra, and molecular weight determination.     

Poly(hydrogen Fluorides) with the Tetramethylammonium Cation: Preparation,Stability Ranges,Crystal Structures, [HnFn+1]− Anion Homology,Hydrogen Bonding F-H…︁F [2]

The melting diagram of the system (CH₃)₄NF? HF was studied between 50 and 100 mole-% HF and from ?185°C to the respective liquidus temperatures (at most 162°C) by difference thermal analysis aided by temperature-dependent X-ray powder diffraction. The system was found to be quasi-binary with the HF-rich intermediary stable compounds (CH₃)₄NF · 2 HF (melting point 110°C), (CH₃)₄NF · 3 HF (20°C, decomposition), (CH₃)₄NF · 5 HF (?76°C, decomposition), and (CH₃)₄NF · 7 HF (?110°C, decomposition), most of which undergo solid-solid phase transitions. Crystal structures were determined of the low-temperature form of (CH₃)₄NF · 2 HF (stable below 83°C, orthorhombic, space group Pbca, Z = 8 formula units per unit cell), the high-temperature form of (CH₃)₄NF · 3 HF (stable above ?87°C, monoclinic, P2/c, Z = 4), and of (CH₃)₄NF · 5 HF (tetragonal, I4 , Z = 2). The structures are those of poly(hydrogen fluorides) (CH₃)₄N[H_nF_n+1] with homologous anions [H₂F₃]^?, [H₃F₄]^?, and [H₅F₆]^?, respectively, formed by strong hydrogen bonding F? H…?F. The anion [H₅F₆]^? is the first one of this composition established by crystal structure analysis. Its structure can be written as [(FH)₂FHF(HF)₂]^? with four equivalent terminal hydrogen bonds of 248.4 pm and a very short central one of 226.6 pm (F…?F distances) through a 4 point of the space group.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. XXXIV. Darstellung und Eigenschaften von 3-(N,N-Dialkylamino)-propylmangan-Verbindungen

Contributions to the Chemistry of Transition Metal Alkyl Compounds. XXXIV. Synthesis and Properties of 3-(N,N-dialkylamino)propyl Manganese Compounds MnCl₂ reacts with lithium organyls of the type R₂N(CH₂)₃Li with formation of definite organomanganese complexes. The pure [(CH₃)₂N(CH₂)₃]₂Mn, [(C₂H₅)₂N(CH₂)₃]₂Mn, [(CH₂)₅N(CH₂)₃]₂Mn and the complexes [(CH₃)₂N(CH₂)₃]₂Mn · LiCl and Li{Mn[(CH₂)₃N(CH₃)₂]₃} · 1,5 THF were isolated. [(CH₃)₂N(CH₂)₃]₂Mn · 2 Li(acac) was obtained as a result of reactions of Mn(acac)₂ and Mn(acac)₃ with the corresponding lithium organyl. The σ-organomanganese(II) derivatives were characterized in detail by elementary analysis, molecular weight determination, ESR- and IR-spectra, conductivity measurements and the magnetic moments.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. XXXV. Zum Reaktionsverhalten von Tetrabenzyltitan gegenüber Lithiumalkylen

Contributions to the Chemistry of Transition Metal Alkyl Compounds. XXXV. Reactions in Tetrabenzyl Titanium/Alkyllithium Systems Organotitanium(IV) complexes of the type Li[(C₆H₅CH₂)₄TiR] (R = CH₃, C₂H₅, n-C₄H₉) were isolated from tetrabenzyl titanium and lithium alkyls at deep temperature. The reddish brown, crystalline compounds decompose between ?30 and 0°C with formation of benzyltitanates(II) which composition differs between Li₂[Ti(CH₂C₆H₅)₄] and Li[Ti(CH₂C₆H₅)₃]. From these complexes pure dibenzyl titanium can be isolated. The reaction mechanism is discussed. Experiments for isolation of a benzyl titanium(III) compound from (C₆H₅CH₂)₄Ti/RLi systems failed in all cases. Recent informations about stable tribenzyl titanium obtained from tetrabenzyl titanium and ethyl lithium could not be confirmed.     

Über Chalkogenolate. 194 [1]: S-Bis(trimethylsilyl)aminoester von Dithiocarbamidsäuren 3. Kristall- und Molekülstruktur vom Methyl-und i-Propylderivat [1]

Inhaltsübersicht. Die Titelverbindungen R₂N–CS–S–N[Si(CH₃)₃]₂ mit Ii = CH₃ bzw. CH(CH₃)₂ kristallisieren orthorhombisch bzw. monoklin: Gitterkonstanten für R = CH₃ (bei ?165°C) a = 8,397(4) Å, b = 11,917(4) Å, c = 31,966 (11) Å, Pbca (Nr. 61), Z = 8. R = CH(CH₃)₂ (bei ?80°C) a =13,183(3) Å, b = 10,873(11) Å, c = 14,865(2) Å, β = 105,86(2)° P2₁/n (Nr. 14), Z = 4. Die Kristallstrukturen wurden unter Verwendung von 4227 bzw. 3 433 symmetrieunabhängigen Reflexen (gemessen bei ?165 bzw. ?80 °C) bestimmt und bis auf Zuverlässigkeitsfaktoren von R = 0,081 bzw. 0,082 verfeinert (R_w = 0,084 bzw. 0,114). Bei beiden Verbindungen ist der C₂N–CS–S–N-Teil des Moleküls nahezu planar. Zwischen dem Thiocarbonyl-S-Atom und dem N-Atom der silylierten Aminogruppe bestehen Wechselwirkungen. On Chalcogenolates. 194. S-Bis (trimethylsilyl) amino Esters of Dithiocarbamic Acids. 3. Crystal and Molecular Structure of the Methyl and i-Propyl Derivative The title compounds R₂N–CS–S–N[Si(CH₃)₃]₂ with R = CH₃ and CH(CH₃)₂, respectively, crystallize orthorhombic and monoclinic, resp.; cell dimensions and space group see “Inhaltsübersicht”. The structures of both compounds have been determined from single crystal X-ray data measured at ?165°C and ?80°C, resp., and refined to R's of 0.081 and 0.082, resp., (R_w = 0.084 and 0.114, resp.) using 4227 and 3433, resp., independent reflections. In both compounds the C₂N–CS–S–N core of the molecule is nearly plane. Between the thiocarbonyl sulfur atom and the nitrogen atom of the amino group interactions exist. In Fortführung unserer Untersuchungen [1, 2] über N, N-Dialkyldithiocarbamidsäure-S-bis(trimethylsilyl)aminoester R₂N–CS–S–N[Si(CH₃)₃]₂ haben wir die Kristall- und Molekülstrukturen der Verbindungen mit R = CH₃ und CH(CH₃)₂ bestimmt. Dabei sollte untersucht werden, welchen Einfluß sterisch anspruchsvollere Alkylgruppen (R = CH₃ → CH(CH₃)₂) auf die Molekülgeo-metrie haben. Eine strukturchemische Charakterisierung dieser Verbindungs-klasse ist bis jetzt noch nicht erfolgt; vgl. die Literaturzusammenstellung bei [3].     

Über die Isolierung von Lithiumhexamethylozirkonat(IV) Li2[Zr(CH3)6]

ZrCl₄ reacts with LiCH₃ at molar ratios 1 :>6 in diethylether/toluene mixtures at about ?40°C to from Li₂[Zr((CH₃)₆]. After removal of the solvents the complex compound can be separated from the ether-free residue by redissolving it in toluene. Evaporation of the toluene at ?23°C yields yellow, crystalline Li₂[Zr(CH₃)₆].     

Über quaternäre Oxoplumbate(IV). Zur Kenntnis von Rb2Li14[Pb3O14] und Cs2Li14[Pb3O14]

On Quaternary Oxoplumbates(IV). On the Knowledge of Rb₂Li₁₄[Pb₃O₁₄] and Cs₂Li₁₄[Pb₃O₁₄] For the first time, Rb₂Li₁₄[Pb₃O₁₄] and Cs₂Li₁₄[Pb₃O₁₄] have been prepared by heating of mixtures of Li₂O, β-?PbO₂”? and Rb₂PbO₃, Cs₂PbO₃ respectively with Li:Pb:A = 14:3:2, (A = Rb, Cs). [Ag-cylinders, sealed under vacuum in Duran-glass ampoule, 590 and 550°C, 40 d, powder (650°C, 200 d, single crystals of Rb₂Li₁₄[Pb₃O₁₄])]. Rb₂Li₁₄[Pb₃O₁₄] is nearly colourless with ivory nuance, Cs₂Li₁₄[Pb₃O₁₄] is pale yellow. According to powder and single crystal investigations, both are isotypic with K₂Li₁₄[Pb₃O₁₄]. Structure refinement of Rb₂Li₁₄[Pb₃O₁₄]: 1015 symmetry independent reflexions, four-circle-diffraktometer PW 1100 (Fa. Philips), ω-scan, MoKα, R = 5.73%, R_W = 5.33%, absorption not considered, space group Immm with a = 1284.71(9), b = 793.90(4), c = 727,35(5) pm, d_x-ray = 4.99 g · cm^?3, d_pyc = 5.01 g · cm^?3, Z = 2. Cs₂Li₁₄[Pb₃O₁₄]: a = 1295.28(12), b = 796.69(8), c = 732.44(7) pm, d_x-ray = 5.31 g · cm^?3, d_pyc = 5.28 g · cm^?3, Z = 2. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Effective Ionic Radii, MEFIR, are calculated.     

Über Chalkogenolate. 145. Trimethylgermanyl- und Trimethylstannylcarbonate

On Chalcogenolates. 145. Trimethylgermyl and Trimethylstannyl Carbonates The hitherto unknown salts of the hemiesters of carbonic acid Li[O₂C? OGe(CH₃)₃] and Li[O₂C? OSn(CH₃)₃] have been prepared by reaction of Li[OGe(CH₃)₃] and Li[OSn(CH₃)₃], respectively, with CO₂ at 0°C. Both compounds were characterized by means of diverse spectoscopic methods.     

Beiträge zur Chemie der Alkylverbindugen von Übergangsmetallen. XXIX. Dibenzylmangan – Darstellung und Reaktionen

Contributions to the Chemistry of Transition Metal Alkyl Compounds. XXIX. Dibenzyl Manganese – Preparation and Reactions Manganese(II) acetylacetonate reacts with tribenzyl aluminium and dibenzyl magnesium forming the yellow complexes 3(C₆H₅CH₂)₂Mn · Al(acac)₃ and (C₆H₅CH₂)₂Mn · Mg(acac)₂ Dibenzyl manganese is also formed at the reaction of dibenzyl magnesium or benzyl magnesium chloride with MnCl₂ · 1.5 THF and was separated as the dioxan complex (C₆H₅CH₂)₂Mn · 2C₄H₈O₂, the ligands of which can be removed to a great extent in vacuum. Dibenzyl manganese reacts with CO₂, CS₂ and SO₂ with insertion into the Mn–C-bonds. The corresponding manganese compounds were isolated and furtherly characterized.     

Very low-pressure pyrolysis (VLPP) of pentynes. II. 4-methylpent-2-yne and 4,4-dimethylpent-2-yne. Heats of formation and resonance stabilization energies of methyl-substituted propargyl radicals

Studies of the unimolecular decomposition of 4-methylpent-2-yne (M2P) and 4,4-dimethylpent-2-yne (DM2P) have been carried out over the temperature range of 903–1246 K using the technique of very-low pressure pyrolysis (VLPP). The primary reaction for both compounds is fission of the C? C bond adjacent to the acetylenic group producing the resonance-stabilized methyl-substituted propargyl radicals, CH₃C??H(CH₃) from M2P and CH₃C?C?(CH₃)₂ from DM2P. RRKM calculations were performed in conjunction with both vibrational and hindered rotational models for the transition state. Employing the usual assumption of unit efficiency for gas-wall collisions, the results show that only the rotational model with a temperature-dependent hindrance parameter gives a proper fit to the VLPP data over the entire experimental temperature range. The high-pressure Arrhenius parameters at 1100 K are given by the rate expressions log k₂ (sec^?1) = (16.2 ± 0.3) ? (74.4 ± 1.5)/θ for M2P and log k₃ (sec^?1) = (16.4 ± 0.3) ? (71.4 ± 1.5)/θ for DM2P where θ = 2.303RT kcal/mol. The A factors were assigned from the results of recent shock-tube studies of related alkynes. Inclusion of a decrease in gas-wall collision efficiency with temperature would lower both activation energies by ～1 kcal/mol. The critical energies together with the assumption of zero activation energy for recombination of the product radicals at 0 K lead to DH⁰[CH₃CCCH(CH₃)? CH₃] = 76.7 ± 1.5, ΔH_f⁰[CH₃CCCH(CH₃)] = 65.2 ± 2.3, DH⁰[CH₃CCCH(CH₃)? H] = 87.3 ± 2.7, DH⁰[CH₃CCC(CH₃)₂? CH₃] = 72.5 ± 1.5, ΔH[CH₃CC?(CH₃)₂] = 53.0 ± 2.3, and DH⁰[CH₃CCC(CH₃)₂? H] = 82.3 ± 2.7, where all quantities are in kcal/mol at 300 K. The resonance stabilization energies of the 1,3-dimethylpropargyl and 1,1,3-trimethylpropargyl radicals are 7.7 ± 2.9 and 9.7 ± 2.9 kcal/mol at 300 K. Comparison with results obtained previously for other propargylic radicals indicates that methyl substituents on both the radical center and the terminal carbon atom have little effect on the propargyl resonance energy.     

Über Chalkogenolate. 144. Darstellung und Eigenschaften von Alkalimetall-t-butyl-carbonaten,Neue Untersuchungen über Trimethylsilylcarbonate

On Chalcogenolates. 144. Synthesis and Properties of Alkali Metal t-Butyl Carbonates. Reinvestigations of Trimethylsilyl Carbonates The t-butyl carbonates M[O₂C? OC(CH₃)₃], where M = Li, Na, K, Rb, Cs, have been prepared by reaction of the corresponding t-butoxide with CO₂ and characterized by means of diverse methods. The equivalent conductivities of the [O₂C? OC(CH₃)₃]^? ion in aqueous solution have been determined and the Stokes radius, the radius of the hydrated ion, and the diffusion coefficient were calculated. The dissociation constant of t-butyl carbonic acid in water at 25°C is K_a = (1.63 ± 0.03)· 10^?8. The thermodynamic data of dissociation were calculated. New data of trimethylsilyl carbonates [O₂C? OSi(CH₃)₃]^? are given.     

Über Chalkogenolate. 151. Untersuchungen über Derivate der N-Thioformyldithiocarbamidsäure. 1. Darstellung und Eigenschaften von N-Thioformyldithiocarbamaten

On Chalcogenolates. 151. Studies on Derivatives of N-Thioformyl Dithiocarbamic Acid. 1. Synthesis and Properties of N-Thioformyl Dithiocarbamates The N-thioformyl dithiocarbamates M[S₂C? NH? CS? H], where M = K, Rb, Cs, Tl, NH₄, [N(ⁿC₄H₉)₄], Na[S₂C? NH? CS? H] · 0.5 H₂O, and Ba[S₂C? NH? CS? H]₂ · 3 HO? CH₂? CH₂? OCH₃ have been prepared by use of partial different procedures. The compounds were characterized with chemical and thermal methods as well as by means of electron absorption, infrared, nuclear magnetic resonance (¹H and ¹³C), and mass spectra. Attempts to synthesize N-thioformyl dithiocarbamic acid were not successful.     

Hydrothermal Syntheses, Crystal Structure and Thermal Behavior of [(CH_3)_2NH_2]_2[B_5O_6(OH)_4]_2·[HCON(CH_3)_2] and [NH_3CH_2CH_2NH_3]_2·[B_(14)O_(20)(OH)_6]

Two novel organic base templated nonmetal borates [(CH₃)₂NH₂]₂[B₅O₆(OH)₄]₂·[HCON(CH₃)₂] ( ? ) and [NH₃CH₂CH₂NH₃]₂[B₁₄O₂₀(OH)₆] ( II ) have been synthesized under hydrothermal conditions, and characterized by elemental analyses, FT‐IR spectroscopy, X‐ray diffraction, and TG‐DTA. Their crystal structures were determined from single crystal X‐ray diffraction. The crystal structure of compound I is characterized by forming a 3D supramolecular structure with large channels along axes b and c through O? H···O hydrogen‐bonding among the [B₅O₆(OH)₄]^? anions. The crystal structure of compound II is characterized by forming a 3D supramolecular structure with large channels along axis a and direction [111] through O? H···O hydrogen‐bonding among the [B₁₄O₂₀(OH)₆]^4? anions. The templating organic amine cations in I and II are both obtained through in situ hydrothermal reactions, and are both located in the channels of the 3D supramolecular structure, respectively. Their thermal behavior has been also investigated.     

Die Reaktion des [(Me3Si)2CH]2Al?CH2?Al [CH(SiMe3)2]2 mit Neopentyllithium: Bildung des {[(Me3Si)2CH]2Al?CH2?Al [CH(SiMe3)2]2CH2CMe3}⊖ [Li(TMEDA)2]⊕

Reaction of [(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂ with Neopentyllithium: Formation of {[(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂CH₂CMe₃} ? [Li(TMEDA)₂]⊕ The recently synthesized methylene bridged dialuminium compound [(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂ reacts with neopentyl lithium in the presence of TMEDA to give the stable {[(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂CH₂ · CMe₃}? [Li(TMEDA)₂]⊕ decomposing at 115°C. The aluminium atoms therein are not additionally bridged, but the new substituent is occupying a terminal position as detected by crystal structure determination. A compound is formed containing a saturated, fourfold coordinated neighbouring a formally unsaturated, threefold coordinated aluminium atom. Due to high sterical restrictions the Al? C bonds are lengthened up to 209.0(3) pm at the alanate site and the Al? C? Al angle in the methylene bridge is extraordinarily enlarged to 144.4(2)°.     

Crystallographic report: The [bis(η5‐methylcyclopentadienyl)titanium(IV)‐bis(N‐methylglycine)] dichloride

The crystal network of [Cp′₂Ti(N?CH₃? Gly)₂]²⁺[Cl^?]₂ (Cp′ = (CH₃)C₅H₄) complex, which crystallizes as a solvate with CH₃OH, is built up with discrete cationic units connected through intermolecular H· · ·Cl bonds. The α‐amino acid ligands are attached through an intramolecular H· · ·O bond within one cationic unit. Copyright © 2004 John Wiley & Sons, Ltd.     

Cationic Allyl Complexes of the Rare‐Earth Metals: Synthesis,Structural Characterization,and 1,3‐Butadiene Polymerization Catalysis

Monocationic bis‐allyl complexes [Ln(η³‐C₃H₅)₂(thf)₃]⁺[B(C₆X₅)₄]^? (Ln=Y, La, Nd; X=H, F) and dicationic mono‐allyl complexes of yttrium and the early lanthanides [Ln(η³‐C₃H₅)(thf)₆]²⁺[BPh₄]₂^? (Ln=La, Nd) were prepared by protonolysis of the tris‐allyl complexes [Ln(η³‐C₃H₅)₃(diox)] (Ln=Y, La, Ce, Pr, Nd, Sm; diox=1,4‐dioxane) isolated as a 1,4‐dioxane‐bridged dimer (Ln=Ce) or THF adducts [Ln(η³‐C₃H₅)₃(thf)₂] (Ln=Ce, Pr). Allyl abstraction from the neutral tris‐allyl complex by a Lewis acid, ER₃ (Al(CH₂SiMe₃)₃, BPh₃) gave the ion pair [Ln(η³‐C₃H₅)₂(thf)₃]⁺[ER₃(η¹‐CH₂CH?CH₂)]^? (Ln=Y, La; ER₃=Al(CH₂SiMe₃)₃, BPh₃). Benzophenone inserts into the La? C_allyl bond of [La(η³‐C₃H₅)₂(thf)₃]⁺[BPh₄]^? to form the alkoxy complex [La{OCPh₂(CH₂CH?CH₂)}₂(thf)₃]⁺[BPh₄]^?. The monocationic half‐sandwich complexes [Ln(η⁵‐C₅Me₄SiMe₃)(η³‐C₃H₅)(thf)₂]⁺[B(C₆X₅)₄]^? (Ln=Y, La; X=H, F) were synthesized from the neutral precursors [Ln(η⁵‐C₅Me₄SiMe₃)(η³‐C₃H₅)₂(thf)] by protonolysis. For 1,3‐butadiene polymerization catalysis, the yttrium‐based systems were more active than the corresponding lanthanum or neodymium homologues, giving polybutadiene with approximately 90 % 1,4‐cis stereoselectivity.     

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.     

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.