Solvent Effects on Isomerization in a Ruthenium Sulfoxide Complex

We report the structure, electrochemistry, and isomerization kinetics for [Ru(bpy)(biq)(OSO)](PF6), where bpy is 2,2′-bipyridine, biq is 2,2′-biquinoline, and OSO is 2-methylsulfinylbenzoate. UV−visible and infrared data are suggestive of intramolecular S→O and O→S isomerization of the sulfoxide. Cyclic voltammetry reveals evidence for isomerization triggered by oxidation and reduction. Of particular note is the variation of the S→O isomerization rate constant in different solvents. The rates were found to be 3.2 (±0.4) s−1 in propylene carbonate, 0.80 (±0.03) s−1 in acetonitrile, and 0.26 (±0.01) s−1 in dichloromethane.