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1Author    H. Erbert, W. Roesky, Nasreddine Benm, Oham Ed, Klaus Keller, Nayla Keweloh, M. Athias, N. Oltem Eyer, GeorgeM. SheldrickRequires cookie*
 Title    Synthesis and Crystal Structure of Seven-M em bered Sulfur Nitrogen Rings Containing Carbon  
 Abstract    The reaction of C1SCF2CF2SC1 and (Me3SiN)2SR2 proceeds with formation of the seven-mem-bered ring compounds 4a, R = CH3, and 4b, R = C2H 5. 4a was shown by an X-ray structure determination to contain a non-planar ring system. 
  Reference    Z. Naturforsch. 42b, 1249—1252 (1987); eingegangen am 5. Mai 1987 
  Published    1987 
  Keywords    Crystal Structure, Sulfur, Nitrogen 
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 TEI-XML for    default:Reihe_B/42/ZNB-1987-42b-1249.pdf 
 Identifier    ZNB-1987-42b-1249 
 Volume    42 
2Author    JohnG. Palmer, PaulA. Doemeny, GerhardN. SchrauzerRequires cookie*
 Title    The Chemical Evolution of a Nitrogenase Model, XXIII. The Nature of the Active Site and the Role of Homocitric Acid in MoFe-Nitrogenase  
 Abstract    The iron-molybdenum cofactor (FeMo-co) of bacterial nitrogenase is a heterometallic cluster of composition MoFe7S9 that is attached to the apoprotein by a coordinative Mo-N bond to the imidazole group of hisa442, and by a Fe-S bond to cysa.215. The molybdenum atom of FeMo-co in the enzyme in addition is coordinated to one molecule of homocitrate (he), which is required for maximal N2 reducing activity. The molybdenum atom in the enzyme-bound FeMo-co thus is hexacoordinated and cannot react with substrates unless free coordination sites are made available. It is proposed that the reactions of the substrates o f nitrogenase occur at a molybdenum active site consisting of a mononuclear molybdenum homocitrate complex attached to hisaAA2 of the apoprotein that in the functional enzyme is generated from FeMo-co by a reversible, redox-linked dissociation of the Fe7S9-c;y5' cluster. Studies with catalytic model systems consisting of complexes of molybdenum with imidazole and hydroxo-carboxylate ligands support this proposal and provide a rationale for the specific activating effect of homocitrate in nitrogenase. 
  Reference    Z. Naturforsch. 56b, 386—393 (2001); received January 17 2001 
  Published    2001 
  Keywords    Nitrogen, Acetylene, Homocitric Acid 
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 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-0386.pdf 
 Identifier    ZNB-2001-56b-0386 
 Volume    56 
3Author    MarcoH. Klingele, Gunther Steinfeld, Berthold KerstingRequires cookie*
 Title    Synthesis and Coordination Chemistry of Novel Binucleating Macrocyclic Ligands with Amine-thioether and Amine-thiophenolate Donor Functions  
 Abstract    The ability of the aromatic tetraaldehyde l,2-bis(4-rm-butyl-2,6-diformylphenylsulfanyl)-ethane (1) to function as a precursor in the preparation of binucleating hexaamine-dithiolate lig­ ands has been investigated. Reductive amination of compound 1 with bis(aminoethyl)amine un­ der medium-dilution conditions affords the macrobicyclic hexaamine-dithioether compound L 1. Deprotection of the [1+2] condensation product gives the corresponding 24-membered hexa-amine-dithiophenol ligand H2L2. The formulation of L 1 as a macrobicyclic amine-thioether was confirmed by an X-ray crystal structure determination of the tetranuclear nickel(II) complex of L 1, [{ (L jN iiC lili^ -C l^K B P h ;) (2b). The formulation of the doubly deprotonated form (L2)2-of H2L2 as a 24-membered amine-thiophenolate ligand was confirmed by an X-ray crystal structure determination of the dinuclear cobalt(III) complex, [(L2)Com(^-OH)](C1 0 4) 2 • Cl (3). The preparation and the crystal structures of the new compounds are described. 
  Reference    Z. Naturforsch. 56b, 901—907 (2001); received June 5 2001 
  Published    2001 
  Keywords    Macrocyclic Ligands, Nitrogen, Sulfur 
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 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-0901.pdf 
 Identifier    ZNB-2001-56b-0901 
 Volume    56 
4Author    HerbertW. Roesky, Pierre Schäfer, Mathias Noltemeyer, GeorgeM. SheldrickRequires cookie*
 Title    Zur Darstellung und Struktur des 1.3-Dichloro-5-N.N-dimethylamino-1.3-dithia-2.4.6-triazins Synthesis and Structure of l,3-Dichloro-5-N,N-dimethylamino-l,3-dithia-2,4,6-triazine  
 Abstract    The six membered ring of composition (CH3)2NCN3S2Cl2 8 a was prepared from N,N-dimethylguanidinhydrochloride and trithiadiazindichloride. 3 a was characterized on the basis of mass, 1 H, 13 C NMR spectra and X-ray structure analysis. Crystals of 3 a are monoclinic, space group P2i/c, with a — 660.3(6), b = 834.5(7), c = 1774.7(15) pm, ß = 112.83(6)° and Z = 4. The C2N unit lies approximately in the plane of the [-CNSNSN-] ring, with both Cl atoms on the same side of the ring. 
  Reference    Z. Naturforsch. 38b, 347—349 (1983); eingegangen am 16. September 1982 
  Published    1983 
  Keywords    Six Membered Ring, Carbon, Sulfur, Nitrogen, X-Ray Structure 
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 TEI-XML for    default:Reihe_B/38/ZNB-1983-38b-0347.pdf 
 Identifier    ZNB-1983-38b-0347 
 Volume    38 
5Author    Susanne Elbel, HeindirkTom DieckRequires cookie*
 Title    Photoelektronenspektren von Verbindungen der V. Hauptgruppe, III 1 Methylhalogenverbindungen MeEHal2 und Me2EHal Photoelectron Spectra of Group V Compounds, III 1 Methylhalogen Compounds MeEHal2 and Me2EHal  
 Abstract    The He I photoelectron spectra of certain MeEHal2 and MeaEHal compounds (E = (N), P, As, Sb; Hal = (F), Cl, Br, J; Me = CH3) are interpreted in terms of a "composite molecule" approach derived for C3v/Cs systems. Although an "internal standard" is missing here, substituent group-orbitals (njjai, C-H) may be classified with respect to their orien-tations in space (R, V, T). Ionisation energies are assigned according to this assumption. PE data of the isoelectronic EMe3/EHal3 compounds and of related molecules (Me2EH, MePH2, CF3PBr2) as well as EHMO calculations with partial inclusion of spin orbit coupling are used to confirm the assignments given for Me2EHal/MeEHal2 series. Correlations between PE ionisation energies (e.g. nE (IE)) and molecular or atomic properties are critically revised and discussed. 
  Reference    (Z. Naturforsch. 31b, 178—189 [1976]; eingegangen am 1. September 1975) 
  Published    1976 
  Keywords    Photoelectron Spectra, Nitrogen, Phosphorus, Antimony Methyl Halides, n-Ionizations 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-0178.pdf 
 Identifier    ZNB-1976-31b-0178 
 Volume    31