Cyclo-thiazenokomplexe von Vanadium(V) Die Kristallstruktur von (AsPh4)2[V(N3)3(N3S2)]2 · CH2Cl2 / Cyclo-thiazeno Complexes of Vanadium(V) The Crystal Structure of (AsPh4)2[V(N3)3(N3S2)]2 · CH2Cl2

Abstract

An improved synthesis for [VCl2(N3S2)]∞, was found in the reaction of VOCl3 with (NSCl)3; when the reaction is performed in H2CCl2 and (NSCl)3 is used in excess, the thiazyl-solvate [VCl2(N3S2) · NSCl]2 is obtained. [VCl2(N3S2)] reacts with AsPh4Cl to form (AsPh4)2[VCl3(N 3S2)]2; this reacts with AgN3 in CH2Cl2 suspension to yield (AsPh4)2[V (N3)3(N3S2)]2 · CH2Cl2. The compounds were characterized by their IR and 51V NMR spectra. The latter are compared with new 51V NMR data for [VO2Cl2]⊖ and [VOCl4]⊖ ; a decrease of 51V shielding in the order [VO2Cl2]⊖ > [VOCl4]⊖ > [VX3(N3S2)]2 2⊖ (X - N3 > Cl) is found, which is interpreted in terms of increasing polarizability of the ligands and of ring contributions to the extreme deshielding observed with the thiazenovanadates. The crystal structure of (AsPh4)2[V(N3)3(N3S2)]2 · CH2Cl2 was determined from X-ray diffraction data (1496 observed reflexions, R = 0.058). It crystallizes in the triclinic space group P 1̄ with one formula unit per unit cell and with the lattice constants a - 1087, b = 1317, c = 1350 pm, α = 58.8, β = 85.9, γ = 68.0°. The structure consists of AsPh4 ⊕ ions, CH2Cl2 molecules and centrosymmetric [V(N3)3(N3S2)]2 2⊖ anions. In the latter. N3S2 ligands are bonded to the V atoms in a chelate manner with short V = N bonds (189 and 172 pm) forming planar VN3S2 rings. The dimerization is accomplished by V -N donor-acceptor interactions (224 pm) involving one N atom of each VN3S2 ring. The vanadium coordination number of 6 is com pleted by three azido groups with V -N bond distances of 200 to 204 pm.