Homolytic N-H Activation of Ammonia: Hydrogen Transfer of Parent Iridium Ammine, Amide, lmide, and Nitride Species

The redox series [Ir-n(NHx)(PNP)] (n = II-IV, x = 3-0; PNP = N(CHCHPtBu2)(2)) was examined with respect to electron, proton, and hydrogen atom transfer steps. The experimental and computational results suggest that the Ir-III imido species [Ir(NH) (PNP)] is not stable but undergoes to the respective Ir-II amido and Ir-III nitrido species. N-H bond strengths are estimated upon reaction with hydrogen atom transfer reagents to rationalize this observation and are used to discuss the reactivity of these compounds toward E-H bond activation.