Redetermination of tris(N,N-diethyldithiocarbamato)antimony(III)

The title compound, [Sb(C5H10NS2)3], was synthesized from Sb2O3, diethylamine, carbon disulfide, hydrochloric acid and sodium hydroxide. The structure has been published previously but H atoms were not included in the model [Raston & White (1976 ▶). Chem. Soc. Dalton Trans. p. 791]. The current determination has significantly higher precision than the original work. The complex has three ligands. The Sb atom is coordinated by three bidentate diethyldithiocarbamate groups, two in an almost planar fashion and the third perpendicular to that plane with a dihedral angle of 86.429 (13)°. One ethyl group is disordered over two positions of equal occupancy.

The title compound, [Sb(C 5 H 10 NS 2 ) 3 ], was synthesized from Sb 2 O 3 , diethylamine, carbon disulfide, hydrochloric acid and sodium hydroxide. The structure has been published previously but H atoms were not included in the model [Raston & White (1976). Chem. Soc. Dalton Trans. p. 791]. The current determination has significantly higher precision than the original work. The complex has three ligands. The Sb atom is coordinated by three bidentate diethyldithiocarbamate groups, two in an almost planar fashion and the third perpendicular to that plane with a dihedral angle of 86.429 (13) . One ethyl group is disordered over two positions of equal occupancy.

Experimental
Crystal data [Sb(C 5

Comment
Dithiocarbamates have found wide practical application as antioxidants and lubricants, as vulcanizing and NO-trapping agents (Fujii et al., 2000), as agents for the froth flotation process of sulfide minerals and for the liquid-liquid extraction of transition metals (Stary et al., 1992;Pazukhina et al., 1997). It has also been found that the extraction efficiency of dithiocarbamate complexes rises in the presence of neutral N, S, O, P-donor molecules, which could potentially imply formation of adducts (Ooi et al., 1967). Besides that, nitrogen donor adducts of dithiocarbamate complexes are also widely used in the preparation of thin semiconductor (O'Brien et al., 1992;Chunggaze et al., 1997;O'Brien et al., 1998) and electroluminescent (Bessergenev et al., 1996;Bessergenev et al., 1997) films of transition metal sulfides, the basis of electronics and solar cell technology (Hovel, 1975). The dithiocarbamate anion (R 1 R 2 NCS 2-=I -) is known to be a strong nucleophile and to form stable complexs with many post-transition metals (Coucouvanis, 1979). Thus, complexes involving Te(IV), Te(II) and Se(II) centres have been reported, and structural studies on these have shown the presence of bidentate chelating ligands (Husebye et al., 1973;Rout et al., 1983). We have synthesized the title compound, C 15 H 30 N 3 S 6 Sb, and report here its crystal structure.
The structure had been reported earlier (Raston & White, 1976), The syntheses and application of the crystal haven't been described in that paper. They mentioned simply that they examined samples of the antimony derivatives recrystallized from benzene solution. The crystal is monoclinic, Z=4, a=14.665 (5) Å, b=13.619 (5)Å, c=12.642 (4)Å, β=99.86 (4)°. These data of the crystal is similar to our crystal.but no hydrogen atoms were included in their structure model. The molecular structure and the atom-numbering scheme of the title compound are shown in Fig. 1. In the molecule, all bond lengths and angles agree well with values found in literature Table 1. The Sb atom is coordinated by three bidentate diethyldithiocarbamato groups, two groups in an almost planar fashion, the thirs group is perpendicular to that plane with a dihedral angle of 86.429 (13)°.

Experimental
Water (200 ml), sodium hydroxide (4 g, 0.1 mol) and diethylamine (7.3 g, 0.1 mol) were added to a three-neck flask in an icewater bath under stirring. Carbon disulfide (7.8 g, 0.1 mol) was added dropwise into this solution during twenty minutes and the mixture was allowed to react for four hours yielding a light yellow liquid. Antimony trioxide (4.6 g, 0.016 mol) was dissolved in hydrochloric acid. The solution was added dropwise into the diethyl dithiocarbamate natrium under stirring and it was confirmed that the resulting solution was acidic. From this solution, a yellow deposit was obtained. It was collected by vacuum filtration, washed with a large amount of water and dried in air. Yellow single crystals were obtained after two weeks upon evaporation of a solution of the reaction product in a mixture of chloroform (5 ml) and methanol (30 ml).

Refinement
Atom C8 and C9 were found to be disordered over two positions with the same site-occupancy factors (0.50/0.50). All hydrogen atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C-H = 0.97, 0.96(-CH 3 ) Å and U iso (H) = 1.2U eq (C), 1.5 U eq (-CH 3 ), respectively.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.