Synthese und Struktur von Re4(μ3-Te)4(TeBr2)4Br8

Synthesis and Structure of Re₄(μ₃-Te)₄(TeBr₂)₄Br₈ Re₄(μ₃-Te)₄(TeBr₂)₄Br₈ is obtained from the elements at 550°C in an evacuated glass ampoule. The diamagnetic compound forms air-stable, metallic lustre black crystals crystallizing in the tetragonal space group I4 with a = 1120.2(2), c = 1393.5(3) pm, and Z = 2. The crystal structure is built up by isolated cluster molecules Re₄(μ₃-Te)₄(TeBr₂)₄Br₈ occupying the centres 4 at 1/2, 1/2, 0 and 0, 0, 1/2. The inner sceleton is formed by a Re₄Te₄ heterocubane unit with short Re? Re distances of 277 and 283 pm, which can be discussed as single bonds. Each Re atom coordinates in addition two Br^? ligands and one TeBr₂ molecule. For Re therefore results the oxidation state +IV. Reaction of Re₄(μ₃-Te)₄(TeBr₂)₄Br₈ with I₂ yields (TeI₄)₄.     

Synthese und Schwingungsspektrum des [Ta2OCl10]2⊖-Ions

Synthesis and Vibrational Spectrum of the [Ta₂OCl₁₀]^2? Ion (PPh₄)₂[Ta₂OCl₁₀] is prepared from NO[TaOCl₄] with tetraphenylphosphonium chloride. The vibrational spectrum is in accordance with the D_4h symmetry of the m?-Oxo-decachloroditantalum(V) ion.     

Synthese und Kristallstruktur eines μ-Methylen-μ-hydrido-dialanats [R2Al(μ-CH2)(μ-H)AlR2]− (R = CH(SiMe3)2)

Synthesis and Crystal Structure of a μ-Methylene-μ-hydrido-dialanate [R₂Al(μ-CH₂)(μ-H)AlR₂]^? (R = CH(SiMe₃)₂) tert-Butyl lithium reacts with the recently synthesized methylene bridged dialuminium compound [(Me₃Si)₂CH]₂Al? CH₂? Al[CH(SiMe₃)₂]₂ 2 in the presence of TMEDA under β-elimination; the thereby formed hydride anion is bound in a chelating manner by both unsaturated aluminium atoms forming a 3c–2e–Al? H? Al bond. The crystal structure of the product shows two independent molecules differing only slightly in bond lengths and angles, but significantly in conformation. While one of the Al₂CH heterocycles deviates little from planarity with a rough C₂ symmetry for the whole anion, the other one is folded with an angle of 21.1° and the arrangement of the substituents is best described by C_s symmetry.     

Synthese und Kristallstruktur des μ-Dinitridosulfato(II)-Komplexes [Na-15-Krone-5]2[μ-(NSN)(MoF5)2]

Synthesis and Crystal Structure of the μ-Dinitridosulfate(II) Complex [Na-15-crown-5]₂[μ-(NSN)(MoF₅)₂] The title compound is formed at room temperature by the reaction of [MoCl₄(NSCl)]₂ with the equivalent amount NaF in acetonitrile in presence of the crown ether 15-crown-5. It forms black, moisture-sensitive crystals that were characterized by an X-ray structure determination (1 756 unique observed reflexions, R = 0.073). Crystal data (19°C): a = 965.5, b = 3 219, c = 1 161.1 pm, β = 95.42°; space group P2₁/n, Z = 4. The structure consists of ion triples in which the [Na-15-crown-5]⁺ ions are associated with the [μ-(NSN)(MoF₅)₂]^2? ions via Na…?F contacts of 215 to 265 pm length. Each of the two MoF₅ units of the anion is linked with one of the N atoms of the dinitridosulfate(II) group; bond angle NSN 103°, MoN bond lengths 172 pm.     

Synthese und Kristallstruktur des Azidoberyllats (Ph4P)2[Be(μ‐OSiMe3)(N3)2]2

Synthesis and Crystal Structure of the Azido Beryllate (Ph₄P)₂[Be(μ‐OSiMe₃)(N₃)₂]₂ (Ph₄P)₂[Be₂F₆] reacts with excess trimethylsilylazide in acetonitrile solution, accompanied by a hydrolytic side‐reaction to give the azido beryllate (Ph₄P)₂[Be(μ‐OSiMe₃)(N₃)₂]₂ ( 1 ) as colourless, non‐explosive crystals. 1 was characterized by IR spectroscopy and by single crystal X‐ray determination. 1 : Space group , Z = 1, lattice dimensions at 193 K: a = 1026.9(1), b = 1184.0(1), c = 1352.1(1) pm, α = 73.50(1)°, β = 74.35(1)°, γ = 64.66(1)°, R₁ = 0.0543. The complex anion of 1 forms centrosymmetric units with symmetry C_i via Be₂O₂ four‐membered rings with Be–O distances of 159.2(7) and 168.7(7) pm, and terminally bonded azide groups.