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

The reaction of [(p-cym)Ru(bpy)Cl]+ (p-cym = η6-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, 1H 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-d4 and 0.74(7) in acetone-d6, respectively, at 50 °C. Kinetic data for the linkage isomerization reaction are also reported.