Synthesis, characterization, and reactivity of alkoxide and hydroxide complexes of rhodium(I) and iridium(I)

Article abstract of DOI:10.1021/om00105a013

Bimetallic alkoxide- and hydroxide-bridged complexes of rhodium(I) and iridium(I), [M(OR)COD]₂ (M = Rh, Ir; R = H, alkyl or aryl group; COD = 1,5-cyclooctadiene), were prepared and used in the synthesis of four-coordinate alkoxide and hydroxide complexes of rhodium(I) and iridium(I) containing the chelating triphosphine ligands ttp {C₆H₅P[CH₂CH₂CH₂P(C ₆H₅)₂]₂} or Cyttp {C₆H₅P[CH₂CH₂CH₂P(C ₆H₁₁)₂]₂}, i.e. M(OR)(ttp) or M(OR)(Cyttp). The basicity of the Rh-OR bond in Rh(OH)(ttp) and Rh(OC₆H₅)(ttp) was tested by use of reactions with weak organic acids; consequently, a series of rhodium carboxylates (e.g., Rh(OC(O)CF₃)(ttp), Rh(OC(O)C₆H₄Br)(ttp), and Rh(OC(O)C₆H₅)(ttp)) was formed. Sulfur dioxide insertion reactions led to metal sulfonates and metal sulfonic acids, i.e. Rh(SO₂OC₆H₆)(ttp)·SO₂, Rh-(SO₂OC₆H₅)(Cyttp)-SO₂, Ir(SO₂OC₆H₆)(ttp)·SO₂, and Rh(SO₂OH)(ttp)·SO₂. The three olefins (CH₂=CH₂, Cl₂C=CClH, and (CN)₂O=C(CN)₂) failed to react with Rh(OH)(ttp) or Rh(OC₆H₅)(ttp) to produce insertion products or simple olefin adducts. All metal complexes were characterized by elemental analysis and infrared and ³¹P{¹H} NMR spectroscopy.