L2,3-edge x-ray absorption near-edge spectroscopy analysis of photoisomerism in solid ruthenium–sulfur dioxide complexes

Ru L2,3 edge x-ray absorption near-edge spectroscopy spectra of four compounds [Ru(SO2)(NH3)4X]Y (X =  water, Y = (±)-camphorsulfonate2; X =water, Y = tosylate2; X =isonicotinamide, Y = tosylate2; X =pyridine, Y = triflate2) are reported before and after optical excitation, which causes photoinduced linkage isomerism of the SO2 ligand. Principal component analysis reveals consistent changes in the spectra upon photoisomerization, suggesting a partial oxidation of the Ru ion. These results demonstrate that x-ray absorption near-edge spectroscopy is an effective means of probing photoinduced linkage isomerism.