|Dichlorotetrakis(dimethyl sulfoxide) ruthenium (II)|
|Molar mass||484.51 g/mol|
|Appearance||Various shades of yellow crystals|
|Solubility in water||water miscible|
|Solubility||nitromethane, chloroform, dichloromethane|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Dichlorotetrakis(dimethyl sulfoxide) ruthenium(II) describes coordination compounds with the formula RuCl2(dmso)4, where DMSO is dimethylsulfoxide. These complexes illustrate linkage isomerism for the ligand DMSO. In these complexes, two chloride anions and four molecules of dmso are coordinated to a central ruthenium (II) core.
The two isomers are cis, fac-RuCl2(dmso-S)3(dmso-O) and trans, mer-RuCl2(dmso-S)4. The trans, mer configuration is kinetically favored, but thermodynamically unstable with respect to the cis isomer. Cis and trans refer to the relative positions of the chloride ligands. The fac/mer describes the binding of the dmso ligands. The notation dmso-S/O refers to the atom through which the dmso molecule is coordinated to the ruthenium center. Thus, dmso-S means that the dmso ligand coordinates through the sulfur atom, whereas dmso-O coordinates through the oxygen atom.
The complexes were first prepared by heating DMSO solutions of ruthenium trichloride under hydrogen atmosphere. An alternative procedure has been developed which avoids hydrogen gas. Ruthenium-dmso complexes inhibit or kill tumors. Trans-RuCl4(dmso-S)L are being tested for their 
These and related dmso-containing ruthenium compounds have attracted attention due to their cancer therapeutic properties.
- Enzo Alessio (2004). "Synthesis and reactivity of Ru-, Os-, Rh-, and Ir-halide-sulfoxide compounds". Chem. Rev. 104 (9): 4203–4242. doi:10.1021/cr0307291.
- B. R. James, E. Ochiai, and G.I. Rempel (1971). "Ruthenium (II) halide dimethylsulphoxide complexes from hydrogenation reactions". Inorganic and Nuclear Chemistry Letters 7 (8): 781. doi:10.1016/0020-1650(71)80091-0.
- I. Bratsos and E. Alessio (2010). "Ruthenium(II) chloro complexes of dimethylsulfoxide". Inorganic Syntheses 35: 148–152.
- Bratsos, I; Serli, B; Zangranko, E; Katsaros, N; Alessio, E. (2007). "Replacement of chlorides with dicarboxylate ligands in anticancer active Ru(II)-DMSO compounds: A new strategy that might lead to improved activity". Inorg. Chem. 46 (3): 975–992. doi:10.1021/ic0613964. PMID 17257042.