Die Gadoliniumcarbidhalogenide Gd4C2X3 (X = Cl,Br)

The Gadolinium Carbide Halides, Gd₄C₂X₃ (X = Cl, Br) The compounds Gd₄C₂X₃ (X = Cl, Br) and Tb₄C₂Br₃ have been prepared by reaction of the metals (RE), REX₃, and C in sealed Ta capsules at 1 100° and 1 300°C, respectively. Monophasic samples of Gd₄C₂Br₃ and Tb₄C₂Br₃ were obtained by reacting stoichiometric mixtures of the starting materials for five days. The needle shaped crystals are bronze-coloured and sensitive to air and moisture. Gd₄C₂X₃ crystallizes in the space group Pnma (No. 62) with lattice constants a = 1 059.6(4), b = 368.4(1), c = 1 962.7(8) pm (Gd₄C₂Cl₃), a = 1 084.4(1), b = 373.0(1), c = 2 036.1(1) pm (Gd₄C₂Br₃). According to Guinier photographs, Tb₄C₂Br₃ is isotypic (a = 1 074.3(2), b = 370.6(1), c = 2 019.4(1) pm). In the crystal structure C is octahedrally coordinated by Gd. The Gd₆ octahedra are linked via common edges to form corrugated layers. The X-anions coordinate all free edges and corners of these layers and connect them via Xⁱ? Xⁱ contacts parallel [001]. Gd₄C₂Br₃ shows metallic conductivity. The magnetic susceptibility follows at high temperatures a Curie Weiss law with an effective moment of 7.95 μ_B. At temperatures below 50 K antiferromagnetic order is observed.     

Gd10C4Cl18 und Gd10C4Cl17, zwei Seltenerdmetall-Clusterverbindungen mit interstitiellen C2-Gruppen

Gd₁₀C₄Cl₁₈ and Gd₁₀C₄Cl₁₇, Two Lanthanoid Cluster Compounds with Interstitial C₂ Units The compounds Gd₁₀C₄Cl₁₈ ( I ) and Gd₁₀C₄Cl₁₇ ( II ) are prepared by heating stoichiometric amounts of GdCl₃, Gd, and graphite in sealed tantalum tubes at 1070 ( I ) and 1 120 K ( II ). Single crystal investigations ( I : P2₁/c, Z = 2, a = 918.2, b = 1 612.0, c = 1 288.6 pm, β = 119.86°; II : P1 , Z = 1, a = 849.8, b = 917.4, c = 1 146.2 pm, α = 104.56°, β = 95.98°, γ = 111.35°) revealed the occurrence of novel Gd₁₀C₄Cl₁₈ clusters. The metal framework is formed by edge-sharing of two Gd₆ octahedra. These are centred by C₂ units (d_{C? C} = 147 pm) and Cl atoms bridge all available edges of the octahedra. The structure of I corresponds to a packing of such quasi molecular clusters, in II they are linked to chains via common Cl atoms. Both structures are discussed in terms of a model of close packed spheres as well as in the concept of condensed clusters.     

3s-Gd2C2Br2: Eine neue Stapelvariante

3s-Gd₂C₂Br₂: An Isomorph with a New Stacking Sequence Gd₂C₂Br₂ has been described in [1]. Here we describe the new stacking variant 3s-Gd₂C₂Br₂ prepared by reaction of stoichiometric amounts of GdBr₃, Gd, and C at 1 320 K. 3s-Gd₂C₂Br₂ with a stacking sequence different to that described in [1] crystallizes in space group C2/m with lattice constants a = 706.6(2) pm, b = 382.7(1) pm, c = 996.7(4) pm and β = 99.95(3)°. In the structure C₂ units are octahedrally surrounded by Gd atoms. Such Gd₆(C₂) octahedra are condensed via edges to form sheets, which are separated by two layers of Br-ions. In contrast to the modification described previously three slabs BrGd(C₂)GdBr are stacked in [103] direction until identity is reached. The isotypic 3s-Tb₂C₂Br₂ has also been prepared at 1 370 K. It is characterized by the lattice constants a = 701.5(3) pm, b = 380.1(1) pm, c = 994.8(3) pm and β = 100.05°.     

Metalloktaederdoppel in den Clusterverbindungen Gd10I16(C2)2 und Gd10Br15B2/Tb10Br15B2

Gd₁₀I₁₆(C₂)₂ and Gd₁₀Br₁₅B₂/Tb₁₀Br₁₅B₂ Cluster Compounds with M₁₀ Twin Octahedra The compound Gd₁₀I₁₆(C₂)₂ can be prepared from Gd metal, GdI₃ and C at 950 °C. It crystallizes in P1 with a = 10.463(4) Å, b = 16.945(6) Å, c = 11.220(4) Å, α = 99.15(3)°, β = 92.68(3)° und γ = 88.06(3)°. Gd₁₀Br₁₅B₂ is formed between 900 und 950 °C, Tb₁₀Br₁₅B₂ between 900 und 930 °C from stoichiometric amounts of the rare earth metals, tribromide and boron. Both compounds crystallize in the space group P1 for Gd₁₀Br₁₅B₂ with a = 8.984(2) Å, b = 9.816(2) Å, c = 10.552(5) Å, α = 91.14(3)°, β = 114.61(3)° and γ = 110.94(3)° and for Tb₁₀Br₁₅B₂ with a = 8.939(4) Å, b = 9.788(3) Å, c = 10.502(2) Å, α = 91.19(3)°, β = 114.51(3)° and γ = 111.10(2)°. In the crystal structures of all three compounds the rare earth metals form edge‐shared Ln₁₀ twin octahedra. In Gd₁₀I₁₆(C₂)₂ the Gd octahedra are centered with C₂ groups (d_C–C = 1.43(7) Å). In Ln₁₀Br₁₅B₂ (Ln = Gd, Tb) the octahedra contain single boron atoms. The clusters are connected through halide atoms to chains [Ln₁₀(Z)₂X X X ]. Adjacent chains are fused threedimensionally via I I for the Gd iodide carbide and via Br Br for the bromide borides of Gd und Tb. It is interesting to see an identical pattern of connection between the chains for the reduced oxomolybdates, e. g. PbMo₅O₈.     

Über die Synthese von Erdalkalimetalldihalogeniden und die Strukturen von Ca3Br2CBN und Sr3Cl2CBN

On the Synthesis of Alkaline-Earth Dihalides and the Structures of Ca₃Br₂CBN and Sr₃Cl₂CBN The reaction of alkaline-earth carbonates with ammonium chloride or bromide yields alkaline-earth dihalides at relatively low temperatures (300°C). Ca₃Br₂CBN and Sr₃Cl₂CBN were synthesized in sealed niobium containers at 950°C from the metal, its dihalide, boron nitride and graphite. The crystal structure of Sr₃Cl₂CBN was refined from single crystal data. Sr₃Cl₂CBN crystallizes isotypic with Ca₃Cl₂CBN in the orthorhombic space group Pnma (No. 62) with a = 1448.4(2) pm b = 405.46(5) pm, c = 1170.0(1) pm. The lattice constants of Ca₃Br₂CBN and Sr₃Cl₂CBN were determined by orthorhombic indexing of the powder patterns (Ca₃Br₂CBN: a = 1444.3(2) pm, b = 390.64(6) pm, c = 1139.2(2) pm; Sr₃Cl₂CBN: a = 1444.0(4) pm, b = 405.27(8) pm, c = 1167.8(2) pm). There was no success in preparing homologues with Barium.     

Disulfidoverbrückte Halogenokomplexe von Molybdän(V) Kristallstrukturen von (PPh3Me)2[Cl4Mo(μ-S2)2MoCl4] · 2 CH2Cl2 und (PPh4)2[Br4Mo(μ-S2)2MoBr4] · 3 CH2Br2

Disulfido-Bridged Halo Complexes of Molybdenum (V). Crystal Sructures of (PPh₃Me)₂ [Cl₄Mo (μ-S₂)₂MoCl₄]. 2 CH₂Cl₂ and (PPh₄)₂[Br₄Mo(μ-S₂)₂MoBr₄]. 3CH₂Br₂ . Mo(S₂)Cl₃ is prepared by an improved method; the i.r. spectrum is reported. In dichloro methane solution it reacts with (PPh₃Me)Cl forming the complex (PPh₃Me)₂[Cl₄Mo(μ-S₂)₂MoCl₄] · 2 CH₂Cl₂. The bromo complex (PPh₄)₂[Br₄Mo(μ-S₂)₂MoBr₄] · 3 CH₂Br₂ is obtained by reaction of MoBr₄ with S₇NH and subsequent treatment of the reaction mixture with PPh₄Br in CH₂Br₂ solution. Both complexes are characterized by i.r. spectra and structural analyses by X-ray methods. (PPh₃Me)₂[Cl₄Mo(μ-S₂)₂MoCl₄] · 2 CH₂Cl₂ crystallizes monoclinic in the space group P2₁/c with two formula units per unit cell (5268 observed independent reflexions, R = 4.0%). The lattice dimensions are: a = 1097 pm, b = 1510 pm, c = 1591 pm, β = 104.4°. (PPh₄)₂[Br₄Mo(μ-S₂)₂MoBr₄] · 3 CH₂Br₂ crystallizes triclinic in the space group P&1macr; with two formula units per unit cell and the lattice constants a = 1328 pm, b = 1573 pm, c = 1719 pm, α = 95.8°, β = 96.3°, γ = 74.1°. Both compounds are of ionical structure with PPh₃Me^⊕ and PPh₄^⊕ cations, respectively, and anions [X₄MO(μ-S₂)₂MoX₄]^2? very similar to each other. The molybdenum atoms are bridged by two disulfido ligands and are bonded directly with a bond length of 286 pm. The terminal halogen atoms add up to coordination number nine at the molybdenum.     

CoSm(SeO3)2Cl,CuGd(SeO3)2Cl,MnSm(SeO3)2Cl,CuGd2(SeO3)4 und CuSm2(SeO3)4: Übergangsmetallhaltige Selenite von Samarium und Gadolinum

CoSm(SeO₃)₂Cl, CuGd(SeO₃)₂Cl, MnSm(SeO₃)₂Cl, CuGd₂(SeO₃)₄ and CuSm₂(SeO₃)₄: Transition Metal containing Selenites of Samarium and Gadolinum The reaction of CoCl₂, Sm₂O₃, and SeO₂ in evacuated silica ampoules lead to blue single crystals of CoSm(SeO₃)₂Cl (triclinic, , Z = 4, a = 712.3(1), b = 889.5(2), c = 1216.2(2) pm, α = 72.25(1)°, β = 71.27(1)°, γ = 72.08(1)°, R_all = 0.0586). If MnCl₂ is used in the reaction light pink single crystals of MnSm(SeO₃)₂Cl (triclinic, , Z = 2, a = 700.8(2), b = 724.1(2), c = 803.4(2) pm, α = 86.90(3)°, β = 71.57(3)°, γ = 64.33(3)°, R_all = 0.0875) are obtained. Green single crystals of CuGd₂(SeO₃)₂Cl (triclinic, , Z = 4, a = 704.3(4), b = 909.6(4), c = 1201.0(7) pm, α = 70.84(4)°, β = 73.01(4)°, γ = 70.69(4)°, R_all = 0.0450) form analogously in the reaction of CuCl₂ and Gd₂O₃ with SeO₂. CoSm(SeO₃)₂Cl contains [CoO₄Cl₂] octahedra, which are connected via one edge and one vertex to infinite chains. The Mn²⁺ ions in MnSm(SeO₃)₂Cl are also octahedrally coordinated by four oxygen and two chlorine ligands. The linkage of the polyhedra to chains occurs exclusively via edges. Both, the cobalt and the manganese compound show the Sm³⁺ ions in eight and ninefold coordination of oxygen atoms and chloride ions. In CuGd(SeO₃)₂Cl the Cu²⁺ ions are coordinated by three oxygen atoms and one Cl^— ion in a distorted square planar manner. One further Cl^— and one further oxygen ligand complete the [CuO₃Cl] units yielding significantly elongated octahedra. The latter are again connected to chains via two common edges. For the Gd³⁺ ions coordination numbers of ?8 + 1”? and nine were found. Single crystals of the deep blue selenites CuM₂(SeO₃)₄ (M = Sm/Gd, monoclinic, P2₁/c, a = 1050.4(3)/1051.0(2), b = 696.6(2)/693.5(1), c = 822.5(2)/818.5(2) pm, β = 110.48(2)°/110.53(2)°, R_all = 0.0341/0.0531) can be obtained from reactions of the oxides Sm₂O₃ and Gd₂O₃, respectively, with CuO and SeO₂. The crystal structure contains square planar [CuO₄] groups and irregular [MO₉] polyhedra.     

Quaternäre Chloride des zweiwertigen Europiums mit dreiwertigen Übergangsmetallen: Synthese und Kristallstruktur von Na6Eu3M4Cl24 (M = Ti,V, Cr)

Quaternary Chlorides of Divalent Europium and Trivalent Transition Metal Ions: Synthesis and Crystal Structure of Na₆Eu₃M₄Cl₂₄ (M = Ti, V, Cr) The reaction of EuCl₂, NaCl and MCl₃ (M = Ti, V, Cr) yields the chlorides Na₆Eu₃M₄Cl₂₄. According to X‐ray single crystal investigations, their crystal structure is a variant of the monoclinic cryolite‐type structure. One crystallographic site is occupied by Na1 and Eu simultaneously. For charge compensation the Na2 site is not fully occupied. In Na₆Eu₃Ti₄Cl₂₄ (P2₁/n, Z = 1/2, a = 663.8(1) pm, b = 718.3(1) pm, c = 953.3(2) pm, β = 91.55(2)°, R_all = 0.0314), Na₆Eu₃V₄Cl₂₄ (P2₁/n, Z = 1/2, a = 660.4(1) pm, b = 715.8(1) pm, c = 946.5(2) pm, β = 91.41(2)°, R_all = 0.0313) and Na₆Eu₃Cr₄Cl₂₄ (P2₁/n, Z = 1/2, a = 654.8(1) pm, b = 706.5(1) pm, c = 945.4(2) pm, β = 91.07(2)°, R_all = 0.0368) the ratio of Na1 : Eu amounts to 5 : 3. The colours of the compounds, orange yellow for M = Ti, orange red for M = V and dark red for M = Cr, indicate electronic interactions between Eu²⁺ and M³⁺.     

Phosphanimin‐ und Phosphaniminato‐Komplexe von Beryllium. Kristallstrukturen von [BeCl2(HNPPh3)2], [BeCl(HNPPh3)2(Py)]Cl und [Be3Cl2(NPPh3)4]

Phosphanimine and Phosphoraneiminato Complexes of Beryllium. Crystal Structures of [BeCl₂(HNPPh₃)₂], [BeCl(HNPPh₃)₂(Py)]Cl, and [Be₃Cl₂(NPPh₃)₄] Tetraphenylphosphonium hexachlorodiberyllate, (Ph₄P)₂[Be₂Cl₆], reacts with lithium phosphoraneiminate, [LiNPPh₃]₆, in dichloromethane to give the three‐nuclear beryllium phosphoraneiminate [Be₃Cl₂(NPPh₃)₄] ( 3 ). As a by‐product the phosphaneimine complex [BeCl₂(HNPPh₃)₂] ( 1 ) can be isolated, which reacts with pyridine to give the ionic complex [BeCl(HNPPh₃)₂(Py)]Cl ( 2 ). On the other hand, the silylated phosphanimine Me₃SiNP(p‐tolyl)₃ ( 5 ) does not react with BeCl₂ or (Ph₄P)₂[Be₂Cl₆] forming the expected phosphoraneiminates. From CH₂Cl₂ solutions only the amino‐phosphonium salt [(C₇H₇)₃PNH₂]Cl ( 4 ) can be obtained. The compounds 1 ‐ 5 are characterized by single X‐ray analyses and by IR spectroscopy. 1 ·C₇H₈: Space group C2/c, Z = 4, lattice dimensions at 193 K: a = 1408.9(2), b = 1750.9(2), c = 1633.2(2) pm, β = 106.50(1)°; R₁ = 0.0385. 1 forms a molecular structure with short Be—N distances of 169.8(3) pm. 2 ·Py: Space group P1¯, Z = 4, lattice dimensions at 193 K: a = 969.5(1), b = 2077.1(2), c = 2266.4(2) pm, α = 72.24(1)°, β = 87.16(1)°, γ = 77.42(2)°, R₁ = 0.0776. 2 forms ion pairs in which the NH atoms of the phosphaneimine ligands act as hydrogen bridges with the chloride ion. The HNPPh₃ ligand realizes short Be—N bonds of 169.0(6) pm, the Be—N distance of the pyridine molecule is 182.5(6) pm. 3 ·3CH₂Cl₂: Space group P1¯, Z = 2, lattice dimensions at 193 K: a = 1333.2(2), b = 1370.2(2), c = 2151.8(3) pm, α = 107.14(1)°, β = 91.39(1)°, γ = 105.15(1)°, R₁ = 0.0917. The structure of the three‐nuclear molecule 3 corresponds with a Be²⁺ ion which is tetrahedrally coordinated by the nitrogen atoms of two {ClBe(NPPh₃)₂}^— chelates. 4 ·CH₂Cl₂: Space group P2₁/c, Z = 4, lattice dimensions at 193 K: a = 1206.6(2), b = 1798.0(2), c = 1096.2(1) pm, β = 97.65(1)°, R₁ = 0.0535. 4 forms dimeric units in which the NH₂ groups of the [(C₇H₇)₃PNH₂]⁺ cations act as hydrogen bridges with the chloride ions to give centrosymmetric eight‐membered rings. 5 : Space group P2₁/n, Z = 4, lattice dimensions at 193 K: a = 1074.3(2), b = 2132.2(3), c = 1075.5(2) pm, β = 110.68(1)°, R₁ = 0.0664. 5 forms molecules with distances PN of 154.6(3), SiN of 168.8(3) pm, and bond angle SiNP of 134.4(2)°.     

Synproportionierung am metallischen Substrat: CsCu2Cl3 und CsCu2Br3

CsCu₂Cl₃ and CsCu₂Br₃ by Synproportionation at the Metallic Substrate CsCu₂Cl₃ and CsCu₂Br₃ are obtained as single crystals via a dry route by synproportionation of mixtures of CsX/2 CuX (X = Cl, Br) and CsCuCl₃, respectively, with the copper of the surface of a closed copper cylinder as the metallic substrate. Lattice constants of CsCu₂Cl₃ (CsCu₂Br₃) are: a = 950.75(9) (987.3(1)), b = 1189.8(2) (1235.5(2)), c = 559.92(6) (581.80(9)) pm, orthorhombic, Cmcm, Z = 4. Details of the Cs? X polyhedra (X = Cl, Br, I) and the double chains of tetrahedra [Cu₂X₃]^? in CsCu₂Cl₃, CsCu₂Br₃, and CsCu₂I₃ are compared.     

Die Kristallstrukturen von [Ph3PMe]Cl·CH2Cl2, [Ph4P]NO3·CH2Cl2 und [Ph4P]2[SiF6]·CH2Cl2

Crystal Structures of [Ph₃PMe]Cl·CH₂Cl₂, [Ph₄P]NO₃·CH₂Cl₂, and [Ph₄P]₂[SiF₆]·CH₂Cl₂ The crystal structures of the title compounds are determined by X‐ray diffraction. In all cases, the included dichloromethane molecules as well as the phosphonium cations are involved to form hydrogen bridges with the anions. [Ph₃PMe]Cl·CH₂Cl₂ ( 1 ): Space group , Z = 2, lattice dimensions at 100 K: a = 890.3(1), b = 988.0(1), c = 1162.5(1) pm, α = 106.57(1)°, β = 91.79(1)°, γ = 92.60(1)°, R₁ = 0.0253. [Ph₄P]NO₃·CH₂Cl₂ ( 2 ): Space group P2₁/n, Z = 4, lattice dimensions at 193 K: a = 1057.0(1), b = 1666.0(1), c = 1358.9(1) pm, β = 100.10(1)°, R₁ = 0.0359. [Ph₄P]₂[SiF₆]·CH₂Cl₂ ( 3 ): Space group , Z = 2, lattice dimensions at 193 K: a = 1063.9(1), b = 1233.1(1), c = 1782.5(2) pm, α = 76.88(1)°, β = 83.46(1)°, γ = 72.29(1)°, R₁ = 0.0332.     

Thiocyanate Compounds of [Nb6Cl12]2+: The structure of A4[Nb6Cl12(NCS)6](H2O)4 (A = K,Rb, NH4)

New compounds of the general formula A₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ (A = K, Rb, NH₄) were synthesized from Nb₆Cl₁₄ and ASCN in aqueous solutions. X-ray structure refinements were performed on single-crystal data of the three compounds. They are isotypic and crystallize with the space group P1 (Z = 1) and the lattice parameters: a = 877.9(3) pm, b = 1176.6(3) pm, c = 1187.0(3) pm, α = 114.29(1)°, β = 98.96(2)°, γ = 100.91(2)° for K₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 1 ); a = 887.6(3) pm, b = 1184.0(4) pm, c = 1195.4(4) pm, α = 114.95(2)°, β = 98.84(2)°, γ = 101.31(2)° for Rb₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 2 ) and a = 886.0(4) pm, b = 1181.1(6) pm, c = 1183.9(6) pm, α = 114.49(2)°, β = 99.48(3)°, γ = 101.53(1)° for (NH₄)₄[Nb₆Cl₁₂(NCS)₆](H₂O)₄ ( 3 ). Each centrosymmetric [Nb₆Cl₁₂(NCS)₆]^4? ion of the isotypic compounds contains six terminal thiocyanate groups being bound to the corners of the octahedral niobium cluster through the nitrogen atoms (d_{Nb? N} = 221.5(6)–224.3(6) pm, bond angles Nb? N? C 168.6(5)–176.4(6)°). The [Nb₆Cl₁₂(NCS)₆]^4? ions are linked via A? S and A? Cl interactions with the A cations. Half of the cations occur to be disordered along two crystallographic sites.     

Gd2IFe2 und Y2Br2Fe2+x: Übergänge zwischen Clusterverbindungen und intermetallischen Phasen

Gd₂IFe₂ and Y₂Br₂Fe_2+x: Intermediates between Cluster Compounds and Intermetallic Phases The compounds Gd₂IFe₂ and Y₂Br₂Fe_2+x were prepared for the first time. Single crystal investigations (Gd₂IFe₂: P6₃/mmc, a = 401.43(5), c = 1 718.0(2) pm; Y₂Br₂Fe_2.23: R3 m, a = 390.66(5), c = 3 402.0(7) pm) revealed trigonal prisms of rare-earth metal atoms centered by Fe atoms and condensed into layers. These intermetallic slices are separated by one (Gd₂IFe₂) or two (Y₂Br₂Fe_2+x) layers of halide atoms. The range of homogeneity of Y₂Br₂Fe_2+x (0.16 ≤ x ≤ 0.23) is due to a partial occupation of the octahedral voids between the Br bilayers. Bonding was analysed via Extended-Hückel calculations. Strong metal—metal bonds occur between the interstitial Fe atoms (d_{Fe? Fe} = 232.7 pm (Gd₂IFe₂) and 226.9 pm (Y₂Br₂Fe_2.23)). Both compounds are metallic conductors. Gd₂IFe₂ orders ferrimagnetically at 280 K. In the case of Y₂Br₂Fe_2+x a magnetic phase transition is observed at 117 K.     

Mo2O3Cl4(Pyridin)4 · CH2Cl2 Synthese,IR-Spektrum und Kristallstruktur

Mo₂O₃Cl₄(Pyridine)₄ · CH₂Cl₂. Synthesis, IR Spectrum, and Crystal Structure Reduction of MoO₂Cl₂(pyridine)₂ with triphenylphosphane in toluene and recrystallisation from CH₂Cl₂ yields brown crystal needles of the complex Mo₂O₃Cl₄(pyridine)₄ · CH₂Cl₂. The compound crystallizes monoclinic in the space group P2₁/c with four formula units per unit cell of the dimensions a = 1 234.6 pm; b = 1 593 pm, c = 1 522.3 pm and β = 105.66° A structural investigation by X-ray methods (3 276 independent observed reflexions, R = 0.033) reveals the molecule with two molybdenum atoms in a distorted octahedral coordination linked by an almost linear Mo? O? Mo bridge with bond distances of 167 and 168 pm, respectively. The chlorine atoms are located in trans-position to the oxygen atoms which have different trans effects: The Mo? Cl bond opposite the bridge (length 242 pm) is 8 pm shorter than the bond in trans position to the terminal oxo ligands. The pyridine nitrogen atoms are in trans position to each other and complete the coordination of the molybdenum atoms. The i.r. spectrum of the compound is reported.     

Nb2Y2X6, a Novel Type of NbIV Compounds with Cross-linked Nb2 and Y2 Dumbbells (Y = Se,Te; X = Br,I)

The compounds Nb₂Se₂Br₆, Nb₂Te₂Br₆, and Nb₂Te₂I₆ were prepared from the elements in sealed quartz ampoulès at 1073 K. The crystalline solids, exhibiting a metallic lustre, are insensitive against moisture and oxygen. All compounds undergo several reversible thermal transitions with temperature (DTA). Beside binary halides only NbYX₃ is present in the gas phase. The structures consist of one-dimensional infinite chains of halogen bridged Nb₂(Y₂)X₄ units containing single side-on bonded Nb₂ and Y₂ dumbbells forming a quasi tetrahedral Nb₂Y₂ cluster (Nb? Nb ? 283.2; 287.5; 293.2 pm; Se? Se ? 230.5 pm; Te? Te ? 267.0; 268.5 pm). The structural and magnetic properties clearly prove the formal oxidation states Nb⁴⁺ and Y^1?, unexpected from stoichiometry. (Structural data: all P2/a (No. 13); Nb₂Se₂Br₆: a = 1254.0(12); b = 689.7(10); c = 662.4(10) pm; β = 98.9(1)°; Z = 2; 1274 hkl; R = 0.066. Nb₂Te₂Br₆: a = 1259.7(13); b = 713.5(9); c = 667.0(9) pm; β = 97.6(1)°; 1557 hkl; R = 0.043. Nb₂Te₂I₆: a = 1347.3(3); b = 742.9(2); c = 714.1(2) pm; β = 98.52(2)°; 1540 hkl; R = 0.026).     

PPh4[As3S3Cl4] und PPh4[As3S3Br4]

PPh₄[As₃S₃Cl₄] and PPh₄[As₃S₃Br₄] When As₂S₃ reacts with PPh₄X and HX in 1,2-C₂H₄X₂ (X = Cl, Br), the title compounds are obtained as minor products; the main products are PPh₄[As₂SX₅]. Their crystal structures were determined by X-ray diffraction. PPh₄[As₃S₃Cl₄]: a = 1187.7, b = 1090.9, c = 1191.8 pm, α = 82.91, β = 88,93, γ = 88.52°; twins with twin plane (100); R = 0.109 for 1618 observed reflexions of one twin crystal. PPh₄[As₃S₃Br₄]: a = 1119.7, b = 1177.5, c = 1204.1 pm, α = 81.59, β = 85.88, γ = 88.25°; R = 0.061 for 2331 observed reflexions. Both compounds crystallize in the space group P1 , Z = 2, and can be considered to be isotypic. Nevertheless, PPh₄[As₃S₃Br₄] does not form twins as PPh₄[As₃S₃Cl₄]. The crystals consist of PPh₄⁺ and [As₃S₃X₄]^? ions. In the anions, the three As atoms of an As₃S₃ ring in the chair conformation are commonly joined to an X atom and each As atom is bonded to one further terminal X atom. Cations and anions are packed in alternating layers.     

Zintl‐Anionen des Siliciums in den Halogeniden La3Cl2Si3 und La6Br3Si7

Zintl Anions of Silicon in the Halides La₃Cl₂Si₃ and La₆Br₃Si₇ La₃Cl₂Si₃ and La₆Br₃Si₇ are prepared at temperatures of around 950 °C from LaX₃ (X = Cl, Br), La metal and Si as starting materials. La₃Cl₂Si₃ crystallizes in C2/m with a = 1802(3), b = 420.6(4), c = 1058(2) pm, β = 97.9(2)°, and La₆Br₃Si₇ in Pmmn mit a = 1686.9(2), b = 412.93(11), c = 1185.2(1) pm. In both compounds the Si atoms are located in trigonal prisms of La atoms, which are connected through common triangular and rectangular faces to form layers. The bromine atoms connect the metal atom double layers. In La₃Cl₂Si₃ the Si atoms form zig‐zag chains, in La₆Br₃Si₇ chains build up from ‐connected Si₁₂ rings. Both compounds are metallic conductors.     

Die Strukturen der 1,3,5-Trisilacyclohexan-Eisendicarbonyl-cyclopentadienylkomplexe C3H6Si3Cl5Fe(CO)2πcp und C3H6Si3Cl4(Fe(CO)2πcp)2

Structures of the l,3,5-Trisilacyclohexane-Iron Dicarbonyl-cyclopentadienyl Complexes and C₃H₆Si₃Cl₅Fe(CO)₂πcp and C₃H₆Si₃Cl₄(Fe(CO₂)πcp)₂ Trisilapentachlorocyclo-hexyl-dicarbonylcyclopentadienyliron C₃H₆Si₃Cl₅Fe(CO)₂πcp 1 and Trisilatetrachlorocyclohexyl-bis(dicarboncyclopentadienyliron)C₃H₆Si₃Cl₄(Fe(CO)₂πcp)₂ 2 are 1,3,5-Trisilacyclohexane complexes substituted by dicarbonylcyclopentadienyliron at one and two silicon atoms of the six-membered ring, respectively. The crystal and molecular structures were determined from single crystals ( 1 ; space group P2₁/a (No. 14); a = 1100.5 pm; b = 2033.9 pm; c = 843.3pm; β = 98.58°; Z = 4; MoKα-radiation; 3142h k l; R = 0.036. 2 ; space group P1 ; (No. 2); a = 1231.1 pm; b = 1267.3 pm; c = 1045.9 pm; α = 113.23°; β = 83.93°; γ = 115.00°; Z = 2; Mokα-radiation; 4196 h k 1; R = 0.065). In both complexes the six-membered rings of the carbosilane ligands are in skew-boat conformation. The bond lengths Fe? Si are 226.4 pm and 228.1 pm, respectively. The distances Si? C and Si? Cl are 186 pm and 206 pm in 1 and 187 pm and 209 pm in 2 . Their different lengths depend on the position in the ligand system and can be explained with the concept of bond orders.     

Darstellung der Dichlormethyleniminium-Salze Cl2CNClH+ MF6− und Cl2CNClCH3+ MF6− (M = As,Sb) und Kristallstruktur von Dichlormethyleniminiumhexachloroantimonat Cl2CNH2+SbCl6−

Synthesis of the Dichloromethyleneiminium Salts Cl₂C?NClH⁺MF₆^? and Cl₂C?NClCH₃⁺ MF₆^? (M = As, Sb) and Crystal Structure of Dichloromethyleneiminium-hyxachloroantimonate Cl₂C?NH₂⁺SbCl₆^? The N-chloro-dichloromethyleneiminium salts Cl₂C=NCIH⁺MF₆^? (M = As, Sb) are prepared by protonationof trichloromethyleneimine in the superacide system HF/MF5 at 195 K. The synthesis of the N-chloro-N-methyl-dichloromethyleneiminium salts Cl₂C?NClCH₃⁺MF₆^? (M = As, Sb) is proceeded by methylation of perchloromethylenimine by CH₃OSO⁺MF₆^? in SO₂ also at low temperature. All salts are characterized by vibrational and NMR spectra. The dichloromethyleneiminiumhexachloroantimonate crystallizes in the space group P2₁/c with a = 971.3(4)pm, b = 1134.0(4)pm, c = 2154.2(7)pm β = 102.04(3)° and Z = 8.     

Synthese von Nitrenkomplexen mit N-Trimethylsilylanilin. II. Charakterisierung und Kristallstruktur der Rhenium(V)-phenylnitren-Komplexe mer-[Re(NPh)Cl3(NH2Ph)(Ph3P)] und trans-[Re(NPh)(OMe)Cl2(Ph3P)2]

Synthesis of Phenylnitrene Complexes with N-Trimethylsilylaniline. II. Characterization and Crystal Structure of the Rhenium(V) Complexes mer-[Re(NPh)Cl₃(NH₂Ph)(Ph₃P)] and trans-[Re(NPh)(OMe)Cl₂(Ph₃P)₂] Reaction of [ReOCl₃(Ph₃P)₂] with N-trimethylsilylaniline yields mer-[Re(NPh)Cl₃(Ph₃P)₂], which reacts under air with excess of N-trimethylsilylaniline to form [Re(NPh)Cl₃ · (NH₂Ph)(Ph₃P)]. Crystallization from CH₂Cl₂/MeOH affords [Re(NPh)(OMe)Cl₂(Ph₃P)₂] as an additional product. [Re(NPh)Cl₃(NH₂Ph)(Ph₃P)] crystallizes in the monoclinic space group P2₁/n with a = 1 192.3(3); b = 1 918.9(3); c = 1 266.3(3) pm; β = 101.71(1)°; Z = 4. The rhenium atom has a distorted octahedral environment with the Cl atoms in meridional positions. The phenyl nitrene ligand is coordinated with an almost linear arrangement Re? N1? C40 = 166.8(6)° and with a bond distance Re?N = 170.5(6) pm. [Re(NPh)(OMe)Cl₂(Ph₃P)₂] · 1/2CH₂Cl₂ crystallizes in the triclinic space group P1 : a = 1 103.1(4); b = 1 227.9(4); c = 1 711.3(5) pm; α = 70.48(3)°; β = 72.71(3)°; γ = 80.03(3)°; Z = 2. The rhenium atom exhibits a distorted octahedral coordination with the Cl atoms and the phosphine ligands in trans positions. As a consequence of the competition of the nitrene ligand and the trans-coordinated methoxy group the Re?;N bond length is slightly lengthened to 173.2(7) pm, while the Re? O bond length of 193.4(6) pm is short. The bond angles Re? N? C70 and Re? O? C80 are 173.3(7)° and 139.1(7)°, respectively.