A Theoretical Study of Hydrogen Transfer Catalyzed by an IrIII PC(sp3)P Pincer Complex

A hydrogen transfer mechanism catalyzed by an Ir-III PC(sp(3))P pincer complex was studied by using DFT, and its efficiency was estimated by using the energetic span model. With the pristine complex, a hydrogen abstraction pathway could not be found, since a ligand dissociation to generate a vacant site is energetically costly. However, a nucleophilic attack of an alkoxide base (present in the reaction mixture) on the carbonyl ligand to form a carboalkoxy ligand generated an anionic catalyst that could easily provide the free site. From there, a hydride abstraction from an isopropyl ion (iPrO(-)) followed by a hydride transfer to acetophenone resulted in an efficient catalytic cycle.