Exploring the Limits of Catalytic Ammonia–Borane Dehydrogenation Using a Bis(<i>N</i>‑heterocyclic carbene) Iridium(III) Complex

Abstract

Ammonia borane dehydrogenation can be catalyzed by a number of organometallic species. [Ir­(κ²-I^<i>t</i>Bu)₂]­[PF₆] (I^<i>t</i>Bu = 1,3-bis­(<i>tert</i>-butyl)­imidazol-2-ylidene) is the most active catalyst for this process that has been reported to date. We explore herein the absolute limits of the use of this and related complexes, including [Ir­(κ²-I^<i>t</i>Bu)₂]­[BAr^F₄], [Ir­(H)₂(I^<i>t</i>Bu)₂]­[BAr^F₄], and [Ir­(κ²-I^<i>t</i>Bu)₂(NH₃)]­[BAr^F₄] (BAr^F₄ = tetrakis­(3,5-bis­(trifluoromethyl)­phenyl)­borate)