Insertion of SO₂ into the Metal−Carbon Bonds of Rhodium and Iridium Compounds, and Reactivity of the SO₂-Inserted Species

Sulfur dioxide has been found to insert into the metal−carbon bonds of both rhodium and iridium alkyl and aryl complexes. The sulfinate ligand can be removed with a strong acid such as HCl, generating free sulfinic acid. Acids with weakly coordinating anions protonate the sulfinate oxygen, but the sulfinic acid remains bound to the metal center. Added sulfinic acids can exchange with the coordinated sulfinate group.