Synthesis and structures of new tetrairidium carbonyl clusters containing phenylgermanium ligands

The reaction of Ir4(CO)11(PPh3) with GePh3H in the presence of Me3NO at room temperature has yielded a new complex Ir4(CO)10(PPh3)(GePh3)(μ-H), 1 in 54% yield by decarbonylation and oxidative addition of the GeH bond of the GePh3H to the cluster. The structure of 1 consists of a tetrahedral Ir4 cluster with a terminal GePh3 ligand and a bridging hydrido ligand. Compound 1 was converted to the GePh2-bridged complex Ir4(CO)10(PPh3)(μ-GePh2), 2 in 95% yield when heated to 40 °C, by the cleavage of a phenyl ring from the GePh3 ligand and the elimination of a molecule of benzene. The reaction of 2 with GePh3H at 65 °C yielded the new tetrahedral Ir4 complex Ir4(CO)7(PPh3)(GePh2)(GePh3)(μ3-η2-GePhC6H4)(μ-H)2, 3 which contains an ortho-metallated bridging μ3-η2-GePh(C6H4) ligand, a terminal GePh3 ligand, a bridging GePh2 ligand and two bridging hydrido ligands. Compound 3 was converted to the complex Ir4(CO)7(PPh3)(GePh2)2(μ3-η2-GePhC6H4)(μ-H), 5 cleavage of a phenyl ring from the GePh3 ligand and the elimination of a molecule of benzene. The structure of 5 consists of a tetrahedral Ir4 cluster with an ortho-metallated bridging μ3-η2-GePh(C6H4) group, two bridging GePh2 ligands and one bridging hydrido ligand. The reaction of 2 with GePh2H2 at 40 °C yielded the tetrairidium complex Ir4(CO)6(PPh3)(GePh2)3(GePh2H)(μ-H)3, 6 with three bridging GePh2 ligands, a terminal GePh2H ligand and three bridging hydrido ligands. All new compounds were fully characterized by IR and 1H NMR spectroscopy, single-crystal X-ray diffraction analyses, and mass spectrometry.