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1996 (1)
1Author    D. Bublitz, A. Franken, W. Preetz, H. ThomsenRequires cookie*
 Title    Darstellung, U B-NMR-Spektren, Schwingungsspektren und Normalkoordi- natenanalyse von cowy'HWcto-Bis-hexahydro-c/oso-hexaborat, [B6H6-B 6H6]2_, sowie Kristallstruktur von [P(C6H5)4 ]2-cöW7 ww^o-[B6H6-B 6H6 ] Preparation, 11B NMR Spectra, Vibrational Spectra and Normal Coordinate Analysis of con ju ncto-B is-h exah ydro-closo-h exaboratQ , [B6H6-B 6H6]2_, and the Crystal Structure of [ P(C6 H5 )4 ] 2 -conjuncto-[B6 H6-B 6 H6 ]  
 Abstract    By reaction of [B6H6]2-with dibenzoylperoxide in dichloromethane conjuncto-[B6H6-b 6h 6]2-is formed. The product could be separated from excess [B6H6]2 by ion exchange chro­ matography on diethylaminoethyl cellulose. The crystal structure of [P(C6H^ ^ -con ju n cto-[B6H6-B 6H6 ] has been determined by single crystal X-ray diffraction analysis; triclinic, space group PI with a = 10.8315(10), b = 11,2422(12), c = 20.340(2) Ä, a = 91.278° (9), ß = 9 0 .\78° (9), 7 = 105.662°(9). The 1 'B NMR spectrum reveals three signals with the intensity ratio 1:1:4, for two equivalent moieties of the conjuncto molecule ion with local C4v symmetry. The IR and Raman spectra of the deprotonated Cs salts of the 1()B, n B and their respective D isotopomers of conjuncto-[B6H5-B6HS]4_ exhibit characteristic shifts. Using averaged crystallographic data and assuming idealized D4h symmetry, normal coordinate analyses have been performed based on a modified valence force field. With a set of eleven force constants (e.g. fd(BB)C 0njU IK.t0 = 2.9, fd(BB)cage = 1.6 mdyn/A) very good agreement between observed and calculated frequencies has been achieved. From strong vibrational coupling with the B6 clusters two vibrations result for the conjuncto B-B bond at 1142/1198 and 292/304cm-1 for 1 'B/I(IB species, respectively. They can be assigned as anti-phase and in-phase motions of the conjuncto B atoms related to the equatorial B4 planes. 
  Reference    Z. Naturforsch. 51b, 609—618 (1996); eingegangen am 7. September 1995 
  Published    1996 
  Keywords    Crystal Structure, n B NMR Spectra, Vibra­ tional Spectra, Normal Coordinate Analysis 
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 TEI-XML for    default:Reihe_B/51/ZNB-1996-51b-0609_n.pdf 
 Identifier    ZNB-1996-51b-0609_n 
 Volume    51