Preparation, Separation, and Characterization of Ruthenium(II) Thiocyanate Linkage Isomers

The reaction of [(p-cym)Ru(bpy)Cl](+) (p-cym = eta(6)-p-cymene; bpy = 2,2'-bipyridine) with SCN- gives a mixture of the linkage isomers [(p-cym)Ru(bpy)(SCN)](+) and [(p-cym)Ru(bpy)(NCS)](+). The linkage isomers were efficiently separated by column chromatography on Hg(NO3)(2)-coated Al2O3. Both isomers were fully characterized by elemental analysis, H-1 NMR and IR spectroscopy, and X-ray crystallography. The equilibrium constant for the conversion of the S-bound to the N-bound isomer was determined to be 0.29(4) in methanol-d(4) and 0.74(7) in acetone-d(6), respectively, at 50 degrees C. Kinetic data for the linkage isomerization reaction are also reported.