2 H ‐Azirines as Ligands: Structural Characterization of the First Neutral and Cationic ( η 5 ‐C 5 Me 5 )Rh( III ) 2 H ‐Azirine Complexes

The synthesis and structural characterization of two azirine rhodium( III ) complexes are described. The stabilization, N ‐coordination and phenylgroup π‐stacking of the highly reactive and strained 3‐phenyl‐2 H ‐azirine by transition metal coordination is observed. The reaction of the dimeric complex [( η 5 ‐C 5 Me 5 )RhCl 2 ] 2 with 3‐phenyl‐2 H ‐azirine (az) in CH 2 Cl 2 at room temperature in a 1:2 molar ratio afforded the neutral mono‐azirine complex [( η 5 ‐C 5 Me 5 )RhCl 2 (az)]. The subsequent reaction of [( η 5 ‐C 5 Me 5 )RhCl 2 ] 2 with six equivalents of az and 4 equivalents of AgOTf yielded the cationic tris‐azirine complex [( η 5 ‐C 5 Me 5 )Rh(az) 3 ](OTf) 2 . After purification, all complexes have been fully characterized. The molecular structures of the novel rhodium( III ) complexes exhibit slightly distorted octahedral coordination geometries around the metal atoms.