Spektroskopische Untersuchung des [FCl2V(15N3S2)]--Ions; Kristallstruktur von [Na-Benzo-15-Krone-5][FCl2V(N3S2)] / Spectroscopic Investigation of the Ion [FCl2V(15N3S2)]-; Crystal Structure of [Na-Benzo-15-Crown-5][FCl2V(N3S2)]

[Na-15-crown-5][FX2V(N3S2)] (X = Cl, Br) and [Na-benzo-15-crown-5][FCl2V(N3S2)] have been prepared by reactions of X2V(N3S2) with sodium fluoride in acetonitrile suspensions in the presence of 15-crown-5 and benzo-15-crown-5, respectively. The 15N-labeled complex [Na-15-crown-5]-[FCl2V(15N3S2)] was also prepared and characterized by 15N, 19F, and 51V NMR spectra, as well as by IR spectroscopy. Whereas the crystal structure of [Na-15-crown-5][FCl2V(N3S2)], owing to disorder of the crown ether molecule, could be refined only to an R-value of 0.16 (space group C2/m, Z = 4, a = 1995.4(11); b = 1016.2(6); c = 1047.2(8) pm; β = 100.83(4)° at —65 °C), the crystal structure of the corresponding [Na-benzo-15-crown-5][FCl2V(N3S2)] was determined without complications. Space group P2,/c, Z = 4, 5565 observed independent reflexions, R = 0.036. Lattice dimensions at 20 °C: a = 1198.9(6); b = 970.3(5); c = 1918.2(10) pm; β = 93.74(3)°. The compound forms ion pairs, in which the sodium atom is seven-coordinated by the oxygen atoms of the crown ether molecule, the fluorine atom and one chlorine atom of the trigonal-bipyramidal [FCl2V(N3S2)]- unit. The vanadium atom is part of a planar VN3S2 ring; fluorine and two nitrogen atoms of the cyclothiazeno ring occupy the equatorial positions.