Refinement of the crystal structure of tetrabutylammonium bis(2- thioxo-1,3-dithiole-4,5-dithiolato)zincate(II), [C16H36N]2[Zn(C3S5)2], at room temperature

Abstract

Source of materialThe synthesis of the title compound involved amodification of literature methods [ 1]. CS 2 (24 ml) was added to degassed dimethyl formamide (DMF, 48 ml), and the mixturewas cooled to 273 K. Sodium (1.45 g) was added to the solution and the mixture was vigorously stirred under cooling until the reaction was completed. Several ml of MeOH were slowly added. To this solution, separate solutions of (i) ZnCl 2 · 2H 2 O(2.13 g) dissolved in 25-28% NH 3 (40 ml) and (ii) Bu 4 NBr (10.12 g) in water (30 ml) were added consecutively with stirring at room temperature. The mixture was stirred overnight. The product was isolated by filtration, washed with water and MeOH, and then solved in acetone. Single crystals of the title compound used for X-ray structure analysis were obtained by evaporation of acetone from the solution held at room temperature. Experimental detailsAll Ha toms were placed in geometrically calculated positions and refined using ariding model with U iso(H) =1.2 Ueq(C). 2-anion has C 2 symmetry with the Zn(II) ion located on the twofold axis. The dmit ligand shows its typical behaviour as abidentate ligand and coordinates the Zn 2+ ion through vicinal exocyclic sulfur atoms of two dmit molecules in adistorted tetrahedral manner. The bond lengths of dmit ligand show typical conjugation character. The C=S double bond (1.666(3) Å)ismuch longer than that of typical C=S (1.599 Å) [10]. The other C-S bonds span the range of 1.709(3) to 1.74 Å (1.819 Å)a nd are essentially single bonds with some double-bond character. The C=C bond lengths of the dmit ion are 1.359(3) Å and very close to the corresponding double-bond value of 1.34 Å.T he S-Zn-S bond angles range from 95.12(2)°to 123.93(4)°.The Zn-Sbond lengths are 2.3391(7) Å and 2.3435(7) Å,respectively. In the crystal packing of the compound, the intermolecular contacts are consistent with avan der Waals type of packing and the structure displays no sizable intermolecular voids. The packing is formed by channels of cations and anions viewing along [010]. Discussion