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'UV Vis Spectra' in keywords Facet   Publication Year 1992  [X]
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1992[X]
1Author    M. =. Re, Tc, X. =. Ci, BrJ. Skowronek, W. PreetzRequires cookie*
 Title    Schwingungsspektren und Normalkoordinatenanalyse der Acetatohalogenodimetallate M 2( 0 2CCH3)4X2, M = Re, Tc; X = CI, Br Vibrational Spectra and Norm al Coordinate Analysis of Acetatohalogenodim etalates M 2( 0 2C CH 3)4X  
 Abstract    The orange-red Tc2(0 2C C H 3)4Br2 has been prepared for the first time by reaction of [Tc2Brg]2_ with glacial acetic acid and acetic anhydride. The IR and R am an spectra have been recorded at 80 K and are compared with those of the analogous com pounds Tc2(0 2CC H 3)4C12, Re2(0 2C C H 3)4Cl2 and Re2(0 2CC H 3)4Br2. The assignment according to the point group D 4h is supported by normal coordinate analysis based on a general valence force field. The quadruple M -M bond is stabilized by the bridging acetato and destabilized by the axial halogeno ligands. The valence force constants fd(MM) are determined to 3,96-4,08 mdyn/A. The inter­ action constants fdd(M M /M X), fdd(M M /M O) and fJM M /M M O) are ab o u t three times high­ er for the technetates as compared with the rhenates. The stronger interaction between oppo­ site bonds in the equatorial ligand sphere is revealed by the stretching interaction constants d d '' which are about two times higher than fdd for M -O bonds at right angles. The strong coupling of the ring co-ordinates implies extensive mixing of the M -O valence and deform ation modes. The electronic spectra of Tc2(0 2CC H 3)4X, agree with those of the corresponding Re com ­ pounds. 
  Reference    Z. Naturforsch. 47b, 482—490 (1992); eingegangen am 10. Oktober 1991 
  Published    1992 
  Keywords    Tetraacetatodihalogenodirhenates, Tetraacetatodihalogenoditechnetates, Vibrational Spectra, UV-Vis Spectra, Normal Coordinate Analysis 
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 TEI-XML for    default:Reihe_B/47/ZNB-1992-47b-0482.pdf 
 Identifier    ZNB-1992-47b-0482 
 Volume    47