Dichlorotetrakis(dimethyl sulfoxide) ruthenium(II) describes

coordination compound A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ' ...

s with the formula RuCl₂(dmso)₄, where DMSO is

dimethylsulfoxide Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula . This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is mis ...

. Both cis and trans isomers are known, but the cis isomer is more common. The cis isomer is a yellow, air-stable solid that is soluble in some organic solvents. These sulfoxide complexes are used in the synthesis of various ruthenium(ii) complexes. They have also attracted attention as possible anti-cancer drugs.

Structure and synthesis

The ''cis'' isomer illustrates

linkage isomer In chemistry, linkage isomerism or ambidentate isomerism is a form of structural isomerism in which certain coordination compounds have the same composition but differ in which atom of the ligand is bonded to the metal. Typical ligands that give ...

ism for the

DMSO Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula . This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is ...

ligand In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...

. One of the two dmso ligands that are ''cis'' to both chloride ligands is ''O''-bonded while the other three dmso ligands are ''S''-bonded. In the ''trans'' isomer, which is also yellow, all four dmso ligands are ''S''-bonded. The ''cis'' isomer is formed thermally, and the ''trans'' isomer is obtained by UV-irradiation of the ''cis'' isomer. The complexes were first prepared in 1971 by heating DMSO solutions of

ruthenium trichloride Ruthenium(III) chloride is the chemical compound with the formula RuCl3. "Ruthenium(III) chloride" more commonly refers to the hydrate RuCl3·''x''H2O. Both the anhydrous and hydrated species are dark brown or black solids. The hydrate, with a var ...

under

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

atmosphere. Modern procedures has been developed which avoids hydrogen gas, either using ascorbic acid or refluxing DMSO to reduce the ruthenium.

Potential applications

RuCl₂(dmso)₄ was identified as a potential anticancer agent in the early 1980s. Continued research has led to the development of several related dmso-containing ruthenium compounds, some of which have undergone early-stage clinical trials.

References

{{Ruthenium compounds Ruthenium complexes Chloro complexes Sulfoxides Ruthenium(II) compounds