Tris(diisopropyl dithiophosphato-κ2 S,S′)ruthenium(III)

In the title complex, [Ru(C6H14O2PS2)3], the coordination environment of the RuIII atom is distorted octahedral, defined by six S atoms from three S,S′-bidentate diisopropyl dithiophosphate ligands. The average Ru—S bond length is 2.41 (1) Å and the average S—Ru—S bite angle is 81.13 (19)°.

In the title complex, [Ru(C 6 H 14 O 2 PS 2 ) 3 ], the coordination environment of the Ru III atom is distorted octahedral, defined by six S atoms from three S,S 0 -bidentate diisopropyl dithiophosphate ligands. The average Ru-S bond length is 2.41 (1) Å and the average S-Ru-S bite angle is 81.13 (19) .

Comment
In recent years there has been an increased interest in ruthenium complexes with sulfur-donor ligands, in part because of the high catalytic activity of RuS 2 unit in various hydrogenation processes (Castillo-Villalón et al., 2008;Chianelli et al., 2009). In the course of our continuous study on ruthenium complexes in a sulfur-rich coordination environment (Leung et al., 2000), we are interested in the homoleptic ruthenium complexes with thiolate ligands, which may be probably designed as processors for the binary RuS 2 nanoparticles (David et al., 2005). Although the ruthenium chemistry of dithio acidic ligands such as dithiocarbamate and dithiocarbonate has been the subject of continuous study, the corresponding ruthenium dithiophosphate chemistry has not been developed much (Wu et al., 2009). Here we report the crystal structure of the title compound, a homoleptic ruthenium complex.
The molecular structure of the title complex is depicted in Fig. 1 (Liu et al., 2005). The bond distances within the di-iso-proposaldithiophosphate ligands of the title complex agree well with those found in the analogous dimethyl-and diethyldithiophosphate complexes of ruthenium (Jain et al., 2000).

Experimental
A mixture of RuCl 3 .H 2 O (209 mg, 0.80 mmol) and KS 2 P(O i Pr) 2 (606 mg, 2.40 mmol) was dissolved in 25 ml of methanol and then heated at reflux for 8 h. During this time the color of the reaction solution was changed from brown to bright red. The solvent was evaporated in vacuo and the residue was redissolved in dichloromethane and then filtered. The filtrate was dried and then recrystallized from diethyl ether/hexane. The red plate-shaped crystals of the title complex were obtained within a week. Yield: 260 mg, 44% (based on Ru). Analysis, calculated for C 18 H 42 O 6 P 3 RuS 6 : C 29.18, H 5.71%; found: C 29.25, H 5.67%.

Refinement
H atoms were placed in geometrically idealized positions and refined as riding atoms, with C-H = 0.98 (CH) and 0.96 (CH 3 ) Å and with U iso (H) = 1.2(1.5 for methyl)U eq (C).

Figure 1
The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level.  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. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.