Synthese und Kristallstruktur des Goldclusters [Au16(AsPh3)8Cl6]

Synthesis and Structures of the Gold Cluster [Au₁₆(AsPh₃)₈Cl₆] Reduction of Ph₃AsAuCl with NaBH₄ in ethanol yields the gold cluster [Au₁₆(AsPh₃)₈Cl₆]. It can be crystallized from dichloromethane/diisopropyl ether in form of dark red, light sensitive crystals with the space group P2₁/n and a = 1777.68(8), b = 3372.7(1), c = 2696.2(1)pm, β = 94.166(6)°, Z = 4). The inner skeleton of the 16 Au atoms consists of a centered icosahedron of which one of the corners binds to three additional Au atoms forming a tetrahedron pendent. The shortest Au–Au distances of 264.3 to 266.6 pm correspond to the bonds to the three external Au atoms. Within the icosahedron the distances between the central atom and the peripheral atoms (273.0–279.1 pm) are distinctly shorter than the distances between the peripheral atoms (283.6–299.0 pm).     

Hexakis(2,4,6‐triisopropylphenyl)cyclotristannoxane – a Molecular Diorganotin Oxide with Kinetically Inert Sn–O Bonds

The single‐crystal X‐ray structure analysis of hexakis(2,4,6‐triisopropylphenyl)cyclotristannoxane, cyclo‐[(2,4,6‐i‐Pr₃‐C₆H₂)₂SnO]₃ ( 1 ), is reported and reveals this compound to contain an almost planar six‐membered ring. Redistribution reactions of 1 with cyclo‐(t‐Bu₂SnO)₃ and t‐Bu₂SiCl₂, respectively, failed and indicate an unusual kinetic inertness of the Sn–O bonds in 1 as compared to related molecular diorganotin oxides containing less bulkier substituents. The redistribution reaction of cyclo‐(t‐Bu₂SnO)₃ with cyclo‐(t‐Bu₂SnS)₂ leads to an equilibrium involving the trimeric diorganotin oxysulphides cyclo‐t‐Bu₂Sn(OSnt‐Bu₂)₂S ( 2 a ) and cyclo‐t‐Bu₂Sn(SSnt‐Bu₂)₂O ( 2 b ).     

New Insights in Asymmetric Tetraorganodistannoxane Ladder Formation. A NMR‐Spectroscopic and Crystallographic study

The syntheses of the asymmetrically substituted tetraorganodistannoxanes [t‐Bu₂(X)SnOSn(Y)(CH₂SiMe₃)₂]₂ ( 1 , X = Y = OH; 2 , X = Cl, Y = OH; 3 , X = Y = Cl) are reported and their structures in solution and in the solid state are characterized by multinuclear NMR spectroscopy and single crystal X‐ray analyses. In toluene, the tetrahydroxy‐substituted derivative 1 is in equilibrium with the organotin oxides cyclo‐[t‐Bu₂Sn{OSn(CH₂SiMe₃)₂}₂O] ( 4 ), cyclo[(Me₃SiCH₂)₂Sn(OSnt‐Bu₂)₂O] ( 5 ), and cyclo‐(t‐Bu₂SnO)₃, and some additional, undefined species containing pentacoordinated tin atoms. In contrast, the dihydroxydichloro‐substituted derivative 2 is inert in solution.     

[RuCl3ind3] and [RuCl2ind4]: Two New Ruthenium Complexes derived from the Tumor‐inhibiting RuIII Compound HInd (OC‐6‐11)‐[RuCl4ind2] (ind = indazole)

Indazolium (OC‐6‐11)‐tetrachlorobis(indazole) ruthenate(III), HInd (OC‐6‐11)‐[RuCl₄ind₂], exhibits excellent results in different tumor models in vitro and in vivo. Substitution reactions of this ruthenium(III) complex are of special interest for a deeper understanding of its interactions with biologically occurring targets and its mode of action. The indazolium complex salt can be transformed to the neutral, meridionally configurated trisindazole complex (OC‐6‐21)‐[RuCl₃ind₃] in solvents like tetrahydrofuran. The X‐ray crystal structure of this complex could be solved (monoclinic space group P2(1)/n, a = 12.441(3), b = 10.415(3), c = 21.635(4) Å, β = 105.02(1)°). In spite of the paramagnetic Ru^III atom most of the coordinated indazole protons could be assigned with the help of two‐dimensional NMR experiments. Additionally, a reduced reaction product of HInd (OC‐6‐11)‐[RuCl₄ind₂] in the physiological solubilizer 2‐pyrrolidone could be isolated and the X‐ray crystal structure of this Ru^II complex, (OC‐6‐12)‐[RuCl₂ind₄], crystallized with two 2‐pyrrolidones, could be solved (monoclinic space group P2(1)/n, a = 12.139(2), b = 10.426(2), c = 14.426(3) Å, β = 100.06(3)°).     

Die Leiterstruktur von LiNb6Cl19

The Ladder Structure of LiNb₆Cl₁₉ LiNb₆Cl₁₉ was obtained from a solid state reaction of Nb powder, NbCl₅, and Li₂C₂ at 530 °C. The structure was refined by single‐crystal X‐ray diffraction (space group Pmma (No. 51), Z = 2, a = 2814.6(1) pm, b = 687.35(5) pm, c = 641.39(3) pm). It contains edge and face bridging [NbCl₆] octahedra forming the motif of a ladder. The parallel alignment of ladders yields a one‐dimensional structure, with lithium ions occupying voids. Each ladder combines characteristic fragments from the niobium chloride structures NbCl₄, A₃Nb₂Cl₉ (A = Rb, Cs), and Nb₃Cl₈. The arrangement of niobium atoms in LiNb₆Cl₁₉ appears to be similar with trigonal niobium clusters obtained in the structure of Nb₃Cl₈. The electronic structures of niobium clusters in Nb₃Cl₈ and LiNb₆Cl₁₉ are compared with each other.     

Struktur und elektrochemische Untersuchung von Nb3Cl8

Structure and Electrochemical Study of Nb₃Cl₈ The compound Nb₃Cl₈ was synthesized from NbCl₅ and niobium metal in a sealed quartz ampoule at 700 °C. Single crystals, obtained from LiCl melt were used for X‐ray structure determination (space group P 3 m1, Z = 2, lattice parameters a = b = 672.95(7) pm, c = 1223.2(2) pm (at 100 K), R1 = 0.029, wR2 = 0.064 for all independent reflections). Electrical resistivity measurements are reported. Electrochemical intercalation of lithium into the structure of Nb₃Cl₈ was studied.     

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.