Azavinylidene and azavinylidene-bridged compounds of iridium and rhodium

Article abstract of DOI:10.1021/om00020a050

The synthesis of the azavinylidene and azavinylidene-bridged compounds Ir(=N=CPh₂)(diolefin)(PCy₃) (5, diolefin = tetrafluorobenzobarrelene (TFB); 6, diolefin = 1,5-cyclooctadiene (COD)) and [Ir(μ-N=CPh₂)(diolefin)]₂ (7, diolefin = COD; 8, diolefin = TFB) is described. The azavinylidene derivatives 5 and 6 were prepared by reaction of the corresponding square-planar methoxy complex Ir(OMe)(diolefin)(PCy₃) with benzophenone imine, whereas the azavinylidene-bridged 7 and 8 were similarly obtained from [Ir(μ-OMe)(diolefin)]₂ (diolefin = COD, TFB). The complexes 7 and 8 react with CO to give [Ir(μ-N=CPh₂)(CO)₂]₂ (9), which affords [Ir(μ-N=CPh₂)(CO)(PCy₃)]₂ (10) in the presence of PCy₃. The preparation of the related compounds [Rh(μ-N=CPh₂)(diolefin)]₂ (diolefin = COD (13), TFB (14)) [Rh(μ-N=CPh₂)(CO)₂]₂ (15), Rh₂(μ-N=CPh₂)₂(CO)₃PCy ₃ (16), and [Rh(μ-N=CPh₂)(CO)(PCy₃)]₂ (17) is also reported. The structure of 14 was determined by an X-ray investigation. 14 crystallizes in the space group P1 with a = 16.468(5) A?, b = 16.569(5) A?, c = 18.139(5) A?, α = 66.03(1)°, β = 74.32(2)°, γ = 89.71(2)°, and Z = 4. The molecular structure reveals that the core of the molecule is formed by a Rh₂N₂ skeleton in a bent configuration.