CNH 2 Bond Formation Mediated by Iridium Complexes

In the presence of phosphanes (PR 3 ), the amido‐bridged trinuclear complex [{Ir(μ‐NH 2 )(tfbb)} 3 ] (tfbb=tetrafluorobenzobarrelene) transforms into mononuclear discrete compounds [Ir(1,2‐η 2 ‐4‐κ‐C 12 H 8 F 4 N)(PR 3 ) 3 ], which are the products of the CN coupling between the amido moiety and a vinylic carbon of the diolefin. An alternative synthetic approach to these species involves the reaction of the 18 e − complex [Ir(Cl)(tfbb)(PMePh 2 ) 2 ] with gaseous ammonia and additional phosphane. DFT studies show that both transformations occur through nucleophilic attack. In the first case the amido moiety attacks a diolefin coordinated to a neighboring molecule following a bimolecular mechanism induced by the highly basic NH 2 moiety; the second pathway involves a direct nucleophilic attack of ammonia to a coordinated tfbb molecule.