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'Stereochemistry' in keywords Facet   Publication Year 1984  [X]
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1Author    CorneliusG. Kreiter, Michael Kotzian, Ulrich Schubert, Robert Bau, MichaelA. BruckRequires cookie*
 Title    Gehinderte Ligandbewegungen in Übergangsmetallkomplexen, X X II I  
 Abstract    [1] Synthese und dynamisches Verhalten von Dicarbonyl(?7-dien)-bis(trimethyl-phosphan)chrom(O) und Dicarbonyl(iy-dien)-bis(trimethylphosphit)chrom(0) Hindered Ligand Motions in Transition Metal Complexes, X X III [1] Syntheses and Dynamic Behaviour of Dicarbonyl(?7-diene)-bis(trimethylphosphane)-chromium(O) and Dicarbonvl(/;-diene)-bis(trimethylphosphite)chromium(0) C r(C O)2[P(CH3)3]2(/7-diene) (9—14) and C r(C O)2[P(OCH3)3]2(?7-diene) complexes (15—20) were prepared photochemically in high yields from Cr(CO)4[P(CH3)3]2 (1) or C r(C O)4[P(OCH3)3]2 (2), respectively, with the dienes 1,3-butadiene (3), rrans-l,3-pentadiene (4), 2-methyl-l,3-butadiene (5), trans,trans-2,4-hexadiene (6), 2-methyl-l,3-pentadiene (7), and 2-ethyl-l,3-butadiene (8). The stereochemistry of 9—20 was determined by IR and N M R spectroscopy. In the case of dicarbonyl-^-r/ww-l ,3-pentadiene-bis(trimethylphosphane)chromium(0) (10) and the cor­ responding trans,trans-2,4-hexadiene complex 12 the X-ray crystal and molecular structure ana­ lyses confirm the spectroscopic conclusions. The distorted octahedral complexes are obtained exclusively as af-isomers. They show a hindered, degenerate isomerization with an intramolecular mutual exchange of the donor ligands. Trigonal prismatic transition states and distorted octahe­ dral intermediates are appropriate models for the explanation of the degenerate isomerization. The activation barriers for the ligand movement were determined by dynamic 3IP-NMR spectro­ 
  Reference    Z. Naturforsch. 39b, 1553—1564 (1984); eingegangen am 14. Juni 1984 
  Published    1984 
  Keywords    77-Diene Complexes, Syntheses, Stereochemistry, Dynamics 
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 TEI-XML for    default:Reihe_B/39/ZNB-1984-39b-1553.pdf 
 Identifier    ZNB-1984-39b-1553 
 Volume    39 
2Author    JohnL. Huppatz, JohnN. PhillipsRequires cookie*
 Title    Cyanoacrylate Inhibitors of the Hill Reaction III. Stereochemical and Electronic Aspects of Inhibitor Binding  
 Abstract    Ethoxyethyl 3-octylamino-2-cyanoacrylate and related com pounds in which the am ino group was replaced by N -C H 3, S, O and CH 2 were synthesized and their activity as inhibitors o f the Hill reaction in isolated pea chloroplasts determ ined. All com pounds show ed m oderate to high activity but there was no obvious correlation between activity and the electronic character o f the ester carbonyl group. The stereochemistry o f the various inhibitor m olecules was deduced from the PMR spectra and the possible influence o f stereochem istry on Hill inhibitory activity discussed. Replacement o f the olefinic proton in the 2-cyanoacrylates with a /?-alkyl substituent was examined and a specific relationship between the length o f the alkyl chain and activity was observed. 
  Reference    Z. Naturforsch. 39c, 617 (1984); received D ecem ber 28 1983 
  Published    1984 
  Keywords    Cyanoacrylates, Inhibitors o f Electron Transport, Hill Reaction, Stereochemistry 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0617.pdf 
 Identifier    ZNC-1984-39c-0617 
 Volume    39