Solid/Gas Reactivity of an Ir(I) Methylidene Complex.

stabilization of known, but solution unstable, methylidene complex [Ir(Bu-PONOP)(=CH)][BAr ] allows single-crystal to single-crystal solid/gas reactivity associated with the {Ir=CH} group to be studied. Addition of H results in [Ir(Bu-PONOP)(H)][BAr ]; exposure to CO forms iridium(I) carbonyl [Ir(Bu-PONOP)(CO)][BAr ], and reaction with NH gas results in the formation of methylamine complex [(Bu-PONOP)Ir(NHMe)][BAr ] via an aminocarbene intermediate. Periodic density functional theory and electronic structure analyses confirm the Ir=CH bond character but with a very low barrier to rotation around the Ir=CH bond. Calculations show that addition of NH to the electrophilic alkylidene carbon gives an initial ammonium ylid intermediate. Stepwise N-H and C-H transfers then form the aminocarbene intermediate as a kinetic product from which two successive C-H couplings lead to the more stable methylamine product.