Photoswitchable Arene Ruthenium Complexes Containing o‑Sulfonamide Azobenzene Ligands

A series
of arene ruthenium complexes containing o-sulfonamide
azobenzene ligands were synthesized and found to exhibit
uncommon coordination pattern with an exocyclic NN bond. Upon
irradiation, these complexes cleanly undergo E → Z photoisomerization followed by thermal Z → E isomerization (upon resting in the dark)
whose rate is dependent on the solvent, the nature of the arene group,
the sulfonamide moiety, and azobenzene substitution, as revealed by
structure–property studies.