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1992 (1)
1991 (2)
1Author    Frederick Kurzer, Zakir KapadiaRequires cookie*
 Title    Bicyclo[2.2.2]octane-2-spirocyclohexanes, Part 2 [1] Reduction Products of Spirodiisophora-3',6-dione  
 Abstract    The reduction o f spirodiisophora-3',6-dione under various conditions occurs exclusively at its 3'-keto-function in the cyclohexane ring. The action o f lithium aluminium hydride yields the 3'-eq-hydroxyketone, while catalytic hydrogenation, hydroboration and the action o f metal borohydride produces the 3'-ax-epimer. The conformers give rise to pairs o f distinct epi­ meric functional derivatives. Anhydrous hydrazine removes the 3'-oxygen function o f the 3',6-dione entirely, with formation o f spirodiisophor-6-one. Catalytic hydrogenation o f the 3'-oxim ino-6-ketone yields the corresponding 3'-amine. The ,3C N M R spectra o f the individu­ al products are assigned and correlated with their structures. 
  Reference    Z. Naturforsch. 46b, 1557—1567 (1991); received February 28 1991 
  Published    1991 
  Keywords    Bicyclo[222]octane-2-spirocyclohexanes, Spirodiisophoranes, Isophorone, 13C N M R Spectra 
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 TEI-XML for    default:Reihe_B/46/ZNB-1991-46b-1557.pdf 
 Identifier    ZNB-1991-46b-1557 
 Volume    46 
2Author    Fluoro, Petra Neumann, K. Urt Dehnicke, Dieter Fenske, G.Erhard BaumRequires cookie*
 Title    Fluoro-, Chloro-und Bromo-Wolfram(VI)-Alkinkomplexe. Die Kristallstrukturen von [K(18-Krone-6)l[WF5( P h -C = C -H ) | * CH3CN und | WCl4( P h -C = C -S e -/ i -C 4H 9)(C H 3CN)|  
 Abstract    -, Chloro-, and Bromo-Tungsten(VI) Alkyne Complexes. The Crystal Structures of [K(18-Crown-6)][WF5(P h ~ C = C -H)] • C H 3CN and [WCl4(P h -C = C -S e -w -C 4 H9)(CH 3CN)] Several tungsten alkyne complexes o f the type [WC14(R -C = C -H) ] 2 and [WC14(R -C = C -R') ] 2 have been prepared by reactions o f WC16 with the alkynes in the presence o f C2C14. Treat­ ing with BrSiMe3 leads to corresponding bromo com plexes, whereas reactions o f N aF and KF, respectively, in acetonitrile solution in the presence o f crown ethers yield the fluoro complexes [N a(l 5-crown-5)][WFs(R -C = C -R ') ] and [K(18-crown-6)][W F5(R -C = C -R ') ] , respectively. All complexes were characterized by IR and l3C N M R spectroscopy. The crystal structures o f [K(18-crown-6)][W F5(P h -C = C -H) ] C H 3CN and [WCl4(P h -C = C -S e -« -C 4 H9)(C H 3C N)] have been determined by X-ray methods. [K(18-crown-6)][W F5(P h -C = C -H ] C H 3 CN: Space group P 2,, Z = 2, 8555 observed unique reflections, R = 0.034. Lattice dim ensions at -7 0 °C: a = 1199.4(3), b = 893.4(2), c = 1351.8(3) pm, ß = 109.73(3)°. The com pound forms ion pairs via three K -F contacts with bond lengths o f 262.0, 282.7, and 293.3 pm; the potassium ion is thus nine-fold coordinated by the six oxygen atoms o f the crown ether molecule and by three fluoride ligands. The alkyne ligand is bonded side on to the tungsten atom o f the [W F5(P h -C = C —H)] unit with WC bond lengths o f 202.4 and 202.6 pm, respectively. [WCl4(P h -C = C -S e -t t -C 4 H9)(C H 3C N)]: Space group P 2 Ja, Z = 4, 4595 observed unique reflections, R = 0.058. Lattice dim ensions at -7 0 °C: a = 1030.3(5), b = 1596.3(9), c = 1170.9(7) pm, ß = 104.28(3)°. The com pound has a molecular structure, in which the tungsten atom is seven-fold coordinated by four chloride ligands, by the two alkyne carbon atom s (WC bond lengths 200 and 203 pm), and in trans position to the latter by the nitrogen atom o f the acetonitrile molecule with a W -N bond length o f 226 pm. 
  Reference    Z. Naturforsch. 46b, 999—1010 (1991); eingegangen am 4. Februar 1991 
  Published    1991 
  Keywords    Tungsten Alkyne Complexes, Synthesis, IR Spectra, 13C N M R Spectra, Crystal Structure 
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 TEI-XML for    default:Reihe_B/46/ZNB-1991-46b-0999.pdf 
 Identifier    ZNB-1991-46b-0999 
 Volume    46 
3Author    Bernd Wrackmeyer, M. Artin Biersack, Hans-Dieter Brendel, M. Ax HerberholdRequires cookie*
 Title    Improvement in 13C NMR Measurements of Ring-Substituted i^-Cyclopentadienyl Metal Complexes  
  Reference    Z. Naturforsch. 47b, 1397—1402 (1992); received M ay 5 1992 
  Published    1992 
  Keywords    V5-Cyclopentadienyl Metal Complexes, 13C N M R Spectra, 13C -'H Couplings, 125T e -13C Couplings, 77S e -13C Couplings 
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 TEI-XML for    default:Reihe_B/47/ZNB-1992-47b-1397.pdf 
 Identifier    ZNB-1992-47b-1397 
 Volume    47