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

Abstract

In crystallo stabilization of known, but solution unstable, methylidene complex [Ir( t Bu-PONOP)(�CH 2 )][BAr F 4 ] allows single-crystal to single-crystal solid/gas reactivity associated with the {Ir�CH 2 } group to be studied. Addition of H 2 results in [Ir( t Bu-PONOP)(H) 2 ][BAr F 4 ]; exposure to CO forms iridium(I) carbonyl [Ir( t Bu-PONOP)(CO)][BAr F 4 ], and reaction with NH 3 gas results in the formation of methylamine complex [( t Bu-PONOP)Ir(NH 2 Me)][BAr F 4 ] via an aminocarbene intermediate. Periodic density functional theory and electronic structure analyses confirm the Ir�CH 2 bond character but with a very low barrier to rotation around the Ir�CH 2 bond. Calculations show that addition of NH 3 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.Article pubs.acs.org/Organometallics