Iridium complexes as catalysts in the hydrogen transfer of isopropanol to acetophenone: Ligand effects and DFT studies

Methoxo-bridged diiridium complexes of the type [{Ir(μ-OMe)(diolefin)}₂] (diolefin = 1,5-cyclooctadiene, tetrafluorobenzobarrelene), in the presence on P- or N-donor ligands, are active catalyst precursors in the catalytic hydrogen transfer of ⁱPrOH to acetophenone. Both the nature of the diolefin and that of additional P- and N-donor ligands have a marked effect in the catalytic outcome of the reactions. DFT theoretical studies have been carried out on the binary catalytic systems composed of the iridium complexes and mono phosphanes (Ir/P = 1/1), which indicated that the operative mechanism in these transformations follows the classic "hydrido" route.