Structural systematics in antimony tris(xanthates): Sb(S2COR)3

Abstract

Abstract Crystallography shows the hexagonal form of Sb(S2COEt)3 to have three-fold symmetry in which the antimony atom is chelated by asymmetrically coordinating xanthate ligands, Sb—S = 2.5204(8) and 3.0603(11) Å. The lone pair of electrons projects out of the triangular face defined by the three weakly coordinating sulfur atoms. The crystal structure comprises layers that stack in an ... ABAB ... fashion in contrast to the previously determined trigonal form. A similar coordination geometry is found in the structure of Sb(S2CO—nPr)3. Molecules aggregate into a supramolecular helical chain via secondary Sb ... S interactions. Crystal data for C9H15O3S6Sb, hexagonal, P63, a = 14.642(4), c = 4.6674(10) Å, V = 866.6(4) Å3, Z = 2, R = 0.021; C12H21O3S6Sb, monoclinic, P21/c, a = 14.671(5), b = 8.898(3), c = 17.185(6) Åb = 111.288(4)°, V = 2090.3(12) Å3, Z = 4, R = 0.042. An analysis of all available Sb(S2COR)3 structures shows the adoption of molecules with C 3 or C s symmetry. In the case of the latter, well defined intermolecular Sb ... S contacts lead to supramolecular double chains. For the structures with C 3 symmetry, supramolecular aggregation patterns are more varied and less dependent on Sb ... S contacts.