Die Reaktion von [Mo6Cl8]X4 mit N-Basen

Reaction of [Mo₆Cl₈]X₄ with N-Bases [Mo₆Cl₈]X₄ (X = Cl, Br, I) in ethanol solution by titration with Ag⁺ showed 4 labil X atoms. The displacement of X^? especially by F^? accelerates the titration decisively. Conductivity measurements in ethanol or acetone showed that [Mo₆Cl₈]X₄ at 25°C behave as weak 1:1-electrolytes. Solutions of [Mo₆Cl₈]X₄ in DMF heated up to 60°C and than lowered to 25°C showed that the compounds in this solvent behave as (potential) strong 2:1-valent electrolytes. From the following compounds the labil halides have been determined by titration with Ag⁺: [Mo₆Cl₈]X₄(Py)₂ (X = Cl, Br), [Mo₆Cl₈]X₄(bipy)₂ (X = Cl, Br, I), [Mo₆Cl₈]X₄(Phenpy)₂ (X = Cl, Br, I), (PyH)₂[Mo₆Cl₈]X₆ (X = Cl, Br); (bipyH)₂[Mo₆Cl₈]I₄Cl₂. Always 4 (respectively 6) labil halides have been observed; exception [Mo₆Cl₈]Cl₄(Py)₂ in acetone (2 labil Cl). Lattice constants and mole volumina for the adducts with pyridin and bipyridin have been determined. The adducts with bipyridin and phenylpyridin are isotypic. Conductivity measurements have been made in different solutions. The decomposition on the thermobalance showed that in [Mo₆Cl₈]Cl₄(Py)₂ the bond of pyridin is weak. The 2 pyridin molecules are evolved at the same time. However [Mo₆Cl₈]I₄(Bipy)₂ loses 1 bipyridin only. (PyH)₂[Mo₆Cl₈]X₆ formed during the first decomposition step the novel compounds (PyH) [Mo₆Cl₈]X₅ (X = Cl, Br). Both compounds are isotypic. They behave in ethanol solution as strong 1:1-valent electrolytes.     

Darstellung von trans-[Mo6Cl8]Cl4Br22−ausgehend von kristallisierten [Mo6Cl8]Cl4(H2O)2 und die Kristallstruktur von [(C6H5)4As]2[Mo6Cl8]Cl4Br2

Preparation of trans-[Mo₆Cl₈]Cl₄Br₂^2? Starting from Crystalline [Mo₆Cl₈]Cl₄(H₂O)₂ and Crystal Structure of [(C₆H₅)₄As]₂[Mo₆Cl₈]Cl₄Br₂ The synthesis of the title compound is successful if the crystallized [(Mo₆Cl₈)Cl₄(H₂O)₂] containing the H₂O molecules in trans-position reacts with HBr + [(C₆H₅)₄As]Br in ethanol in a heterogeneous reaction. The X-ray structure investigation confirms the existence of discrete trans-Br-substituted cluster anions of composition [(Mo₆Cl₈)Cl₄Br₂]^2? in the crystal. The reaction in homogeneous solutions proceeds to Br-enriched compounds. [(C₆H₅)₄As]₂[(Mo₆Cl₈)Cl₄Br₂] crystallizes in the triclinic space group P¯1 with a = 11.071(2), b = 11.418(2), c = 12.813(2) Å, α = 116.10(2), β = 95.27(2) and γ = 94.41(2)° (?133°C). The crystal structure at ?133°C was determined from single crystal X-ray diffraction data (R₁ = 0.026). The [(Mo₆Cl₈)Cl₄Br₂]^2?-anions are not completely ordered but distributed statistically among the three positions which are possible within the limits of the ordered [Mo₆Cl₈]-cores (ratio 11:5:4). The frameworks of the anions consist of Mo₆ cluster units with (slightly distorted) octahedral arrangement of the metal atoms (d(Mo? Mo): 2.600(1) up to 2.614(1) Å), which are coordinated by the halogeno ligands in a square-pyramidal manner. The details of the structure will be discussed and compared with similar [(Mo₆X₈)Y₄] cluster units (X, Y ? Cl, Br).     

Trennung von [Mo6Cl8−nIn]Cl4 in Komplexe mit n = 0–3 durch Gegenstromverteilung

Disintegration of [Mo₆Cl_8−nI_n]Cl₄ in Complexes with n = 0–3 by Countercurrent Distribution [Mo₆Cl_8−nI_n]Cl₄ with n = 1–1, 2 have been disintegrated into [Mo₆Cl₈]Cl₄, [Mo₆Cl₇I₁]Cl₄, [Mo₆Cl₆I₂]Cl₄, and [Mo₆Cl₅I₃]Cl₄ by means of the countercurrent distribution and the yields before and after annealing at 400°C are compared with probability calculation on the basis of possible permutationes. Annealing leads to the occupation of the ligand places in agreement with the calculation. The lattice constants of the dihydrates of the complexes mentioned above are determind.     

Das Addukt von BiCl3 mit Mo6Cl12: [BiCl]-Hanteln in der Struktur von [BiCl][Mo6Cl14]

The Adduct of BiCl₃ and Mo₆Cl₁₂: [BiCl] Dumbbells in the Structure of [BiCl][Mo₆Cl₁₄] MoCl₃ reacts under decomposition to MoCl₂ and Cl₂ with BiCl₃ in a sealed evacuated glass ampoule at 550 °C to form light red crystals of [BiCl][Mo₆Cl₁₄]. The crystal structure determination (monoclinic, C 2/c, a = 1268.1(4) pm, b = 1304.6(3) pm, c = 2571.9(8) pm, β = 91.79(3)°, Z = 8) shows that the structure is built of [(Mo₆Cl₈)Cl₆] units containing nearly regular octahedral Mo₆ clusters. These units are arranged in the motiv of a cubic closest packing. The octahedral interstices contain [BiCl] dumbbells with a Bi–Cl bond length of 249 pm. The coordination sphere of the Bi atom is completed by six weaker Bi–Cl-contacts of 275 to 308 pm length to a distorted monocapped trigonal prism. Neglecting the secondary Bi–Cl bonds, the title compound can be formulated as [(BiCl)²⁺][(Mo₆Cl₁₄)^2–].     

Heterogeneous reactions of K3[MoCl6] and K4[Mo2Cl8] with nitrogen oxide

Summary The heterogeneous reactions of K₃[MoCl₆] and K₄[Mo₂Cl₈] with nitrogen oxide were examined. The products,i.e. the nitrite complex K₄[Mo₂Cl₆(NO₂)₂], KCl and NOCl were identified and the mechanism associated with their production proposed. The nitrosyl complex is an intermediate, while the final product is thought to be a dimer with two chloride bridges and with nitrite groups, coordinated through O-atoms, as chelating ligands. The nitrite complex was characterised spectroscopically.     

pH-controlled photoinduced electron transfer in the [(Mo6Cl8)L6]-calix[4]resorcine-dimethylviologen system

A pH-controlled photoinduced electron transfer in the supramolecular system [(Mo(6)Cl(8))L(6)]-calix[4]resorcine-dimethylviologen is reported.     

Einige Reaktionen von Phenoxy-amino-silanen mit Alkaliamiden

Zusammenfassung Es werden einige weitere Austauschreaktionen von Phenoxygegen Aminogruppen am Si-Atom mit Hilfe von (substitutierten) Alkaliamiden beschrieben. Sie sind in den Gl. (1) bis (7) niedergelegt. Dabei wird nur eine Phenoyxygruppe pro Molekül ausgetauscht, selbst bei Anwesenheit mehrerer Phenoxysilylgruppen und Anwendung eines größeren Alkaliamidüberschusses.The substitution of phenoxy by amino groups by means of alkali amides according equations (1)–(7) was feasible. However, even with several phenoxysilyl groups per molecule and an excess of alkali amide it was not possible to replace more than one phenoxy group.72. Mitt.:U. Wannagat, P. Schmidt undM. Schulze, Angew. Chem.79, 409 (1967).Mit Auszügen aus der DissertationG. Schreiner, Techn. Hochschule Graz, 1965.     

Synthesis and Crystal Structure of [Ca（DMF）6][Mo6Br8Cl6]

1INTRODUCTION Molybdenum(II)halide clusters containing[Mo6-X8]4 cores have been the subject of interest for over five decades[1].This octahedral cluster-type comple-xes comprise an important,and in a sense archetypal,class of higher nuclearity transition metal cluster com-plexes.Their high symmetry,photochemical and pho-tophysical properties as well as structural relation-ships to cluster complexes of other elements exhibit significant interest[2].In addition,there is a structural simila…     

Zwei neue Silicat-Chloride mit zweiwertigem Europium: LiEu3[SiO4]Cl3 und Li7Eu8[SiO4]4Cl7

Two New Silicate-Chlorides with Divalent Europium: LiEu₃[SiO₄]Cl₃ and Li₇Eu₈[SiO₄]₄Cl₇ LiEu₃[SiO₄]Cl₃ was prepared by reaction of LiCl with Eu₂SiO₄ and Li₇Eu₈[SiO₄]₄Cl₇ from Li with Eu₂O₃, SiO₂ and LiCl. The crystal structures of LiEu₃[SiO₄]Cl₃ (Pmna, a = 946.95(13); b = 699.52(8); c = 1 368.0(2) pm; Z = 4; R1 = 0.0325, R2_w = 0.0642) and Li₇Eu₈[SiO₄]₄Cl₇ (P2₁/c; a = 851.85(5); b = 948.62(7); c = 1 679.0(2) pm; β = 96.221(8)°; Z = 2; R1 = 0.0352, R2_w = 0.0744) were determined from four-circle diffractometer data. LiEu₃[SiO₄]Cl₃ contains [Li(SiO₄)₂] units and LiCl₆ octahedra while in Li₇Eu₈[SiO₄]₄Cl₇ larger ?lithosilicate”? groups are found. In both structures, the Eu²⁺ ions are coordinated mostly eightfold by O^2? and Cl^? ligands.     

Über das Lithiumchloromolybdat Li[Mo6Cl13]

On the Lithium Chloromolybdate Li[Mo₆Cl₁₃] Li[Mo₆Cl₁₃] was obtained as single phase product from a solid state reaction of MoCl₅, Mo powder, and LiCl at 800 °C. The structure as refined by single crystal X‐ray diffraction, contains one‐dimensional [Mo₆Cl Cl Cl ]^– chains, formed by Cl^a–a bridges. Lithium ions are located in tunnels along the chain‐direction, each of them being surrounded by a distorted tetrahedral arrangement of outer chlorine ligands (Cl^a) belonging to four different clusters.     

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.     

Thermodynamik und Kinetik der Xa-Substitution bei den Komplexen [W6Cl8]X6a(2−) und [Mo6Cl8]X6a(2−) (X = Cl,Br, J)

Thermodynamics and Kinetics of the X^a-Substitution of [W₆Cl₈]X₆^a(2?) and [Mo₆Cl₈]X₆^a(2?) Complexes; (X = Cl, Br, I) The title subject has been investigated in different solvent mixtures (see “Inhaltsübersicht”). In some cases the progress of the reaction has been followed by an emf method; in most cases the reaction was stopped after definite times by precipitation of the oxiniumsalts. Thermodynamics. For equilibria of the type (a) one finds the constant \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm C} = \frac{{[{\rm Br}^{\rm a} ][{\rm Cl}^ - ]}}{{[{\rm Cl}^{\rm a} ][{\rm Br}^ - ]}} $\end{document}, where [Br^a] and [Cl^a] mark the total number of Br or Cl occupying X^a-positions of the complex. The X^a-positions are thermodynamically equivalent, the substitution proceeds statistically, so that the steps of reaction (a) with the equilibrium constants K₁ to K₆ are given by \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm K} = \frac{{{\rm W}({\rm hin})}}{{{\rm W}({\rm r\ddot uck})}} \cdot {\rm C} $\end{document} if W(hin) and W(rück) describe the probability of the forward and the back reaction. Similarly in some simple complexes (e. g. Irx₆^2?);PdX₄^2? the statistical effect plays a dominating role. The kinetics may be described as (b) The aquotation step is rate determining. Consequently the reaction of the first order. Rate constants for the forward and the reversed reaction between 0 and 25°C have been measured. The activation energy is ≈ 18 kcal. With the molybdenum complexes the X^a-substitutions is about 10 times faster as with the tungsten complexes.     

Interaction of [Mo6Cl14]2− with H2Se: Selective Preparation of [Mo6SeCl13]3−

Reaction of [Mo₆(μ₃-Cl)₈Cl₆]²⁻ with H₂Se, generated in situ from ZnSe and 4 M HCl under hydrothermal conditions lead to the substitution of one or two bridging chlorides, depending on the reagents ratio. With the Mo₆/ZnSe 1:3 molar ratio [Mo₆(μ₃-SeCl₇)Cl₆]³⁻ forms selectively in high yield. Further substitution is more hindered, and even at 1:20 cluster-to-selenide molar ratio a mixture of [Mo₆(μ₃-SeCl₇)Cl₆]³⁻ and [Mo₆(μ₃-Se₂Cl₆)Cl₆]⁴⁻ is formed. The products were characterized by X-ray, Raman spectra and electrospray ionization mass spectrometry.