Characterization of a Rhodium(III)−Imine−Orthometalated Imine Complex: Reversible C−H Activation of a Coordinated Imine

Solutions of cis-[Rh(PPh3)2(solv)2]PF6 (solv = acetone or MeOH) react at room temperature
under Ar with benzophenone imine to yield cis-[Rh(PPh3)2(η1-NHCPh2)2]PF6 (3), but
depending on reaction conditions, one of the imine ligands undergoes orthometalation to
give [RhH{NHC(Ph)(o-C6H4)}(HNCPh2)(PPh3)2]PF6 (2) with trans-phosphines; this is the
first recorded complex containing an imine in its η1-form and as an η2-moiety formed via
orthometalation. Complexes 2 and 3 are characterized by elemental analysis, 1H and 31P{1H} NMR spectroscopy, and, in the case of 2, an X-ray crystal structure.