Photo- and thermal-induced linkage isomerizations in a peroxydithiocarbamate-Ru complex

Previous work has shown that mono-oxygenation of Ru(bpy)₂(N,N′-dimethyldithiocarbamate)⁺, 1, yields two different linkage isomers: S,S-bound 2a and O,S-bound 2b, as well as a stable dioxygenate, Ru(bpy)₂(N,N-dimethylthiocarbamate-sulfinate-S,S)⁺, 3. In this report, the interconversion of the two peroxydithiocarbamate isomers was investigated using photolysis and thermal activations. The O,S-bound 2b undergoes phototriggered linkage isomerization to form the less stable S,S-bound 2a at low temperatures in non-coordinating solvents. The more reactive S,S-bound 2a then converts to O,S-bound 2b by a thermal isomerization at moderate temperatures in polar solvents. The different solvent and temperature dependences suggest distinct pathways for the two isomerizations.