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'Cluster' in keywords Facet   Publication Year 2001  [X]
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1Author    AlexanderV. Shtemenko3, AlexanderA. Golichenko3, KonstantinV. DomasevitchbRequires cookie*
 Title    Synthesis of Novel Tetracarboxylato Dirhenium(III) Compounds and Crystal Structure of [Re2 (l-Adamantylcarboxylate)4Cl2] * 4 CHC13  
 Abstract    The coordination compounds o f the general formula Re2 (1^ 4X2 (X = Cl, Br; L = 1 -adamantyl-carboxylate and 1 -adamantylacetate) have been prepared and characterized by means of UV-VIS spectroscopy (20000 cm-1 , 6 —► 6*). The crystal and molecular structure of Re2(AdCOO)4Cl2 • 4 CHCI3 solvate was determined by X-ray diffraction. The units Re2(AdCOO)4Cl2 adopt a centrosymmetric dinuclear array with each metal atom coordinated in a distorted octahedron comprising one rhenium and one chlorine atoms (Re-Cl 2.505(2) A) and four carboxylate oxygen atoms in the equatorial plane. The rhenium-rhenium separation of 2.2300(5) A corre­ sponds to quadruple bond between the metal atoms. All R e-0 bonds have an almost uniform length (2.017(4) -2.032(4) A) and do not differ essentially from the parameters reported for related compounds. The closest environment of the Re2(AdCOO)4Cl2 molecules in the crystal comprises weak Cl— HC hydrogen bonds with the chloroform molecules and significantly shortened van der Waals contacts Cl— Cl, 3.46 A. 
  Reference    Z. Naturforsch. 56b, 381—385 (2001); received December 15 2000 
  Published    2001 
  Keywords    Rhenium, Clusters, Adamantane 
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 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-0381.pdf 
 Identifier    ZNB-2001-56b-0381 
 Volume    56 
2Author    Andreas Nägele3, Cynthia Dayb, Abdessadek Lachgarb, H.-Jürgen Meyer3, Sonderdruckanforderungen An, ProfH. Dr, -J MeyerRequires cookie*
 Title    Interpenetrierende Clusterstränge in der Kristallstruktur von Ko,77Nb6Cl15 Interpenetrating Cluster Chains in the Structure of Ko.77Nb6Cl15  
 Abstract    The solid state reaction of KCl, NbCl5 and Nb powder at 760 °C yielded black crystals of KNb6Cl15. The structure of the compound has been determ ined using single-crystal X-ray m e­ thods. KNb6Cli5 crystallizes in the orthorhombic space group Pmma (no. 51) with lattice constants a = 1780.1(2), b = 1341.4(1), and c = 925.5(1) pm, Z = 4, and R1 = 0.039 for all 2727 observed reflec­ tions. [ (N ^ C l ^ C l ^ 3'3]-anions in the structure are linked via two Cla a bridges to form one set of li­ near and one set of kinked chains along the cry­ stallographic c and a directions. Four remaining Cla a bridges interconnect both sets of chains to a three-dim ensional network. The potassium occu­ pancy on a 4k site was refined to a value of 0.384(3) consistent with the formula K0 77Nb6C li5. Ternäre Niobchloride des Formeltyps A Nb6Cl15 wurden bereits verschiedentlich beschrieben. Ver­ bindungen mit A = Li [1] und Na [2] kristallisieren kubisch (Ia3d) mit identischen Schweratomstruk-turen. Die Alkalim etall-Ionen Li (KZ = 4) und Na (KZ = 6) besetzen in den Strukturen A N b6Cl15 aber unterschiedliche Splitlagen und sind dyna­ misch fehlgeordnet. Die V ertreter mit A = In und TI [3] kristallisieren orthorhombisch (Pmma). Ihre Kationen befinden sich in zweifach überdachten, würfelförmigen Cl-Umgebungen (KZ = 10). Die Kenntnis des Formeltyps A N b6Cl15 mit schweren Alkalim etallen ist noch unvollständig. Einkristall­ 
  Reference    Z. Naturforsch. 56b, 1238—1240 (2001); eingegangen am 26. Juli 2001 
  Published    2001 
  Keywords    Niobium, Chloride, Cluster 
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 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1238_n.pdf 
 Identifier    ZNB-2001-56b-1238_n 
 Volume    56