Carbon disuiphide activation. A CS-bonded derivative of vanadocene derived from a carbon disuiphide complex: synthesis and structure of [V(η-C5H5)2(CS2)] and [V(η-C5H5)2(SCSMe)][I3]

Abstract

The addition of the ‘carbenoid’[V(cp)₂](cp =η-C₅H₅) to CS₂ gives the known [V(cp)₂(CS₂)] complex containing the CS-side-bonded CS₂, as confirmed by an X-ray analysis. A significant lengthening of one of the C–S bonds is observed [1.666(4)Å: average of the two independent molecules in the asymmetric unit] with respect to the non-bonded CS moiety [1.617(4)Å], Alkylation of the co-ordinated CS₂ produces a vanadium dithiomethoxycarbonyl complex [V(cp)₂(CS₂Me)I][ν(CS)(Nujol) at 1 125 cm^–1] which reacts with I₂ giving [V(cp)₂(CS₂Me)][I₃][ν(CS)(Nujol) at 1 105 cm^–1]. The trend in C–S bond distances, as deduced from X-ray analyses, allows the CS-bonded dithiomethoxycarbonyl group to be described as a three-electron ligand, with carbenoid character for the carbon atom bonded to the metal. In both the complexes [V(cp)₂(CS₂)] and [V(cp)₂(CS₂Me)][l₃] the two cp are bent away so as to make a cavity in the equatorial plane for the CS₂ and SCSMe ligands, which are nearly coplanar with the vanadium atom. Crystallographic details: [V(cp)₂(CS₂)], space group P2₁/c,a= 11.803(2), b= 12.310(2), c= 14.463(3)Å, β= 90.07(3)°, Z= 8, final R factor = 0.030 for 2 857 observed reflections; [V(cp)₂(CS₂Me)][I₃], space group P2₁/n, a= 9.377(2), b= 26.601(3), c= 7.579(1)Å, β= 108.95(2)°, Z= 4, final R factor = 0.084 for 2 842 observed reflections.