Fluoro-, Chloro- und Bromo-Wolfram(VI)-Alkinkomplexe. Die Kristallstrukturen von [K(18-Krone-6)][WF5(Ph – C≡C – H)] · CH3CN und [WCl4(Ph – C ≡ C – Se – n – C4H9)(CH3CN)] / Fluoro-, Chloro-, and Bromo-Tungsten(VI) Alkyne Complexes. The Crystal Structures of [K(18-Crown-6)][WF5(Ph — C ≡ C — H)] · CH3CN and [WCl4(Ph — C ≡ C — Se — n — C4H9)(CH3CN)]

Petra Neumann, Kurt Dehnicke, Dieter Fenske, Gerhard Baum
1991 Zeitschrift für Naturforschung. B, A journal of chemical sciences  
Several tungsten alkyne complexes of the type [WCl4(R – C ≡ C – H)]2 and [WCl4(R – C ≡ C — R′)]2 have been prepared by reactions of WCl6 with the alkynes in the presence of C2Cl4. Treating with BrSiMe3 leads to corresponding bromo complexes, whereas reactions of NaF and KF, respectively, in acetonitrile solution in the presence of crown ethers yield the fluoro complexes [Na(15-crown-5)][WF5(R – C ≡ C – R′)] and [K(18-crown-6)][WF5(R – C ≡ C – R ′)], respectively. All complexes were
more » ... by IR and 13C NMR spectroscopy. The crystal structures of [K(18-crown-6)][WF5(Ph – C ≡ C – H)] · CH3CN and [WCl4(Ph – C ≡ C – Se – n – C4H9)(CH3CN)] have been determined by X-ray methods. [K(18-crown-6)][WF5(Ph – C ≡ C – H] · CH3CN: Space group P21 Z = 2, 8555 observed unique reflections, R = 0.034. Lattice dimensions at -70 °C: a = 1199.4(3), b = 893.4(2), c = 1351.8(3) pm, β = 109.73(3)°. The compound forms ion pairs via three K – F contacts with bond lengths of 262.0, 282.7, and 293.3 pm; the potassium ion is thus nine-fold coordinated by the six oxygen atoms of the crown ether molecule and by three fluoride ligands. The alkyne ligand is bonded side on to the tungsten atom of the [WF5(Ph – Cs ≡ C – H)]- unit with WC bond lengths of 202.4 and 202.6 pm, respectively. [WCl4(Ph – C ≡ C – Se – n – C4H9)(CH3CN)]: Space group P21/a, Z = 4,4595 observed unique reflections, R = 0.058. Lattice dimensions at -70 °C: a = 1030.3(5), b = 1596.3(9), c = 1170.9(7) pm, β = 104.28(3)°. The compound has a molecular structure, in which the tungsten atom is seven-fold coordinated by four chloride ligands, by the two alkyne carbon atoms (WC bond lengths 200 and 203 pm), and in trans position to the latter by the nitrogen atom of the acetonitrile molecule with a W – N bond length of 226 pm.
doi:10.1515/znb-1991-0805 fatcat:bc2keb5pb5culbepr45doyzq5i