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'Stereochemistry' in keywords Facet   Publication Year 1991  [X]
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1Author    Dieter Sellmann+, W. Olfgang Kern, Adelgunde Holzmeier, Georg Pöhlmann, M. Atthias, MollRequires cookie*
 Title    Übergangsmetallkomplexe mit Schwefelliganden, LXVI  
 Abstract    Substitutions-und Additionsreaktionen an Molybdän-und Wolfram-Schwefel-Zentren von |M (Cl)(NO)('S4)], M = Mo, W, mit Thiolaten SR" (R = Me, 'Pr, w Bu, Ph) und PM e3 ('S4'2-= l,2-Bis(2-mercaptophenylthio)ethan(2-)) Transition M etal Complexes with Sulfur Ligands, LXVI* Substitution and A ddition Reactions at M olybdenum and Tungsten Sulfur Centres of [M(Cl)(NO)('S4')], M = M o, W, with Thiolates SR " (R = Me, 'Pr, "Bu, Ph) and PM e3('S4'2~ = l,2-Bis(2-mercaptophenylthio)ethane(2-)) Since substrate addition and elim ination reactions are essential reactions o f metal sulfur centres in oxidoreductases, we investigated the substitution o f chloride in [Mo(C1)(NO)('S4')](1) ('S4'2-= l,2-Bis(2-m ercaptophenylthio)ethane(2-)) [4] and in the anal­ ogous tungsten complex [W (Cl)(NO)('S4')](2). The chloride ligands in 1 and 2 can easily be substituted by thiolates to give [M (SR)(NO)('S4')] (M = M o, R = Me 3a, 'Pr 3b, "Bu 3c, Ph 3d; M = W, R = Me 4 a , Ph 4b). For these substitution reactions an associative mechanism is suggested. The SR~ ligands act probably as o-n four electron donor ligands to give metal centres with an 18 electron configuration as also found in the amido complexes [M o(N R 2)(NO)('S4')] [4]. 1 and 2 react with PM e3 to yield the adducts [M(PMe3)(Cl)(NO)('S4')] (M = Mo 5, W 6), w hose N M R spectra indicate the formation o f two stereoisomers in a ratio o f about 2:3. 
  Reference    Z. Naturforsch. 46b, 1349—1356 (1991); eingegangen am 28. Januar 1991 
  Published    1991 
  Keywords    Sulfur Complexes, Synthesis, Reactions, Stereochemistry, M olybdenum, Tungsten 
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 TEI-XML for    default:Reihe_B/46/ZNB-1991-46b-1349.pdf 
 Identifier    ZNB-1991-46b-1349 
 Volume    46 
2Author    Prostereogenic Mo-Centers, Dieter Sellmann+, Franz Grasser, Falk Knoch, M. Atthias, MollRequires cookie*
 Title    Übergangsmetallkomplexe mit Schwefelliganden, LXV  
 Abstract    Diastereospeziflsche Alkylierung von [M o(NO)2(S2')2]2 zu chiralen |M o(N O)2(/RS4')l-Komplexen mit chirotopen und prostereogenen Mo-Zentren** Transition Metal Complexes with Sulfur Ligands, LXV* Diastereospecific Alkylation o f [M o(NO)2('S2')2]2" to Chiral [M o(NO)2('RS4')] Complexes with Chirotopic In order to investigate how chirotopicity and stereogenicity o f metal centers influence the enantioselectivity o f metal centered reactions the stereogenic properties o f metal centers in chiral complexes have to be varied without changing their electronic character. Diastereospe­ cific alkylation o f [M o(N O)2('S2')2]2~ by racemic 1,2-dibromopropane and 1,2-dibromobutane yields the title complexes [M o(N O)2('M eS4')] and [M o(N O)2('EtS4')] that differ from the parent compound [M o(N O)2('S4')] with respect to the stereogenicity o f the metal center and allow fu­ ture investigations o f the question raised above. 
  Reference    Z. Naturforsch. 46b, 1343—1348 (1991); eingegangen am 21. März 1991 
  Published    1991 
  Keywords    M olybdenum Nitrosyl Sulfur Complexes, X -R ay, Diastereospecific Alkylation, Stereochemistry 
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 TEI-XML for    default:Reihe_B/46/ZNB-1991-46b-1343.pdf 
 Identifier    ZNB-1991-46b-1343 
 Volume    46