AZAVINYLIDENE AND AZAVINYLIDENE-BRIDGED COMPOUNDS OF IRIDIUM AND RHODIUM

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(mu-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(mu-OMe)(diolefin)]2 (diolefin = COD TFB). The complexes 7 and 8 react with CO to give [Ir(mu-N=CPh2)(CO)2]2 (9), which affords [Ir(mu-N=CPh2)(CO)(PCY3)]2 (10) in the presence of PCy3. The preparation of the related compounds [Rh(mu-N=CPh2)(diolefin)]2 (diolefin = COD (13), TFB (14)), [Rh(mu-N=CPh2)(CO)2]2 (15), Rh2(mu-N=CPh2)2(CO)3PCy3 (16), and [Rh(mu-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 P1BAR with a = 16.468(5) angstrom, b = 16.569(5) angstrom, c = 18.139(5) angstrom, alpha = 66.03(1)-degrees, beta = 74.32(2)-degrees, gamma = 89.71(2)-degrees, and Z = 4. The molecular structure reveals that the core of the molecule is formed by a Rh2N2 skeleton in a bent configuration.