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'Molecular Structure' in keywords Facet   Publication Year 1988  [X]
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1Author    Otto Mündt, Heinz Riffel, Gerd Becker, Arndt SimonRequires cookie*
 Title    Element—Element-Bindungen, IV [1] Molekül-und Kristallstruktur des Tetramethyldiphosphans und -diarsans Element—Element Bonds, IV [1] Molecular and Crystal Structure of Tetramethyldiphosphane and -diarsane  
 Abstract    The molecular and crystal structures of the isotypic compounds tetramethyldiphosphane 1 and -diarsane 2 have been determined by single crystal X-ray diffraction (monoclinic; C2/m; Z = 2; 1/2: -155/-144 °C\a = 540.6(2)/555.8(2); b = 1131.0(6)/l 136.7(6); c -602.5(2)/612.8(2) pm;/? = 97.31(3)/95.24(3)°;P-P 221.2(1)/As-As 242.9(1) pm). In accordance with the crystallographically imposed symmetry 2/m, the molecules adopt antiperiplanar conformation. Their crystal structures are closely related to those of the homologues tetramethyldistibane 3 [1] and -dibismuthane 4 [3]. As found for the latter compounds, the E —E units (E = P, As) are also aligned in linear chains, but the intermolecular E---E contacts (P-P 381/As---As 370 pm) do not allow any extended interaction between molecules, which otherwise would result in thermochromic effects. 
  Reference    Z. Naturforsch. 43b, 952—958 (1988); eingegangen am 29. Februar 1988 
  Published    1988 
  Keywords    Tetramethyldiphosphane, Tetramethyldiarsane, Conformation, Molecular Structure, Crystal Structure 
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 TEI-XML for    default:Reihe_B/43/ZNB-1988-43b-0952.pdf 
 Identifier    ZNB-1988-43b-0952 
 Volume    43 
2Author    M. Veith, F. Goffing, V. HuchRequires cookie*
 Title    On the Coordination of Different Main Group Metals with a Special, Chelating Silazane  
 Abstract    The c/s-isomer of the silazane H ; L (1) (L = [N'Bu][Me]Si(N r Bu) 2 Si[Me][N r Bu]) has been used as a ligand to main group metals. By displacing the hydrogen atoms of 1 the compounds L(MgMe) 2 (4), L(MgCl) 2 (5) and L(Li)(InMe 2) (6) have been obtained. According to the 'H NMR spectra the structures of 4—6 are very similar: a polycyclic, cubane-like Si 2 N 4 M 2 framework results from the special atomic arrangements and from intramolecular Lewis acid-base interactions between the metals M and the nitrogen atoms. Divalent metals and metal-centered groups can also be incorporated into 1. In the latter case a seco norcubane-like polycycle Si 2 N 4 M is produced as confirmed by X-ray structure determinations of LGaMe (8) and LSb + InCl 4 ~ (11). LInMe (7) and LSn (9) seem to adopt the same tricyclic structure as 8, although the 'H NMR spectra are not consistent with a rigid molecule (low symmetry), but rather with a fluxional behaviour (high symmetry). When 5 is allowed to react with sodium/naphthalene in THF part of the magnesium is reduced and LMg(THF) : (12) is formed. An X-ray structure determination of 12 reveals the compound to be only bicyclic with the magnesium atom coordinated by two nitrogen and two THF oxygen atoms. 
  Reference    Z. Naturforsch. 43b, 846—856 (1988); eingegangen am 8. Februar 1988 
  Published    1988 
  Keywords    Metal Amides, Molecular Structures, 'H NMR Spectra X-Ray, Chelated Metal Atoms 
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 TEI-XML for    default:Reihe_B/43/ZNB-1988-43b-0846.pdf 
 Identifier    ZNB-1988-43b-0846 
 Volume    43