How Inert are Osmium−Ligand Bonds? A Combined Thermal, Photochemical and Electrochemical Case Study With a Click Tripodal Ligand

The first examples of osmium(II) complexes of the type [Os(L)(dmso)Cl]⁺ (L=tripodal ligand) are reported. Photoactivation is shown to be a convenient route for performing ligand substitution reactions in such complexes. Photochemical bond activation works where thermal and electrochemical routes fail. Drastic differences are presented in the reactivity of the Os complexes with the pyridine-containing ligands versus the triazole-containing ligands. A detailed experimental and theoretical investigation into photochemical bond activation reactions is presented.