Reactivity of Ir–NSiN Complexes: Ir-Catalyzed Dehydrogenative Silylation of Carboxylic Acids

This work describes the results from the studies on the potential of [Ir(μ-Cl)(cod)]₂ (cod=1,5-cyclooctadiene) as metallic precursor for the preparation of Ir(NSiN) complexes (NSiN=fac-bis-(pyridine-2-yloxy)methylsilyl). The reaction of [Ir(μ-Cl)(cod)]₂ with bis-(pyridine-2-yloxy)methylsilane enabled the synthesis of [Ir(H)(Cl)(NSiN)(η²-cod)] with an uncommon η²-coordination mode for the cod ligand. The application of Ir–NSiN species as catalysts precursors for the dehydrogenative silylation of carboxylic acids was also explored. The outcomes from these catalytic studies revealed a clear influence of the ancillary ligand on the catalytic activity of Ir–NSiN species. Thus, whereas [Ir(H)(CF₃SO₃)(NSiN)(coe)] shows poor catalytic activity, the related complex [Ir(H)(CF₃CO₂)(NSiN)(coe)] with a trifluoroacetate ligand was demonstrated to be a highly active catalyst precursor.