Solvothermal synthesis, crystal structure, and properties of the first zinc containing thioantimonate(III) [Zn(tren)]2Sb4S8•0.75 H2O

Yellow crystals of the title compound were obtained under solvothermal conditions reacting elemental Zn, Sb, and S in a solution of tris(2-aminoethyl)amine (= tren) and water. The compound crystallises in the monoclinic space group P2(1)/c with a=13.0247(7), b=22.308(2), c=12.1776(6) Angstrom, and beta=105.352(6)degrees. In the structure of [Zn(tren)](2)Sb4S8.0.75 H2O two [Zn(tren)](2+) cations are bound to the [Sb4S8](4-) anion via S atoms. The Zn2+ ions are in a trigonal bipyramidal environment of four N atoms of the tetradentate tren ligand and one S atom of the [Sb4S8](4-) anion. The anion is formed by SbS3 and SbS4 units which share common corners and edges. The interconnection mode yields three different non-planar Sb2S2 heterorings. The shortest intermolecular Sb-S distance amounts to about 3.7 Angstrom, and taking this long separation into account undulated chains running along [001] are formed with the water molecules residing in the pocket-like cavities. Upon heating the compound decomposes in one step starting at about 240degreesC. The final decomposition product was identified as ZnS and Sb2S3 by X-ray powder diffractometry. Additionally, spectroscopic data as well as synthetic procedures for [Zn(tren)](2)Sb4S8.0.75 H2O are reported.