H-atom site exchange in an iridium trans -dihydrogen/hydride complex, trans -[Ir(H)(η 2 -H 2 ) (iPr)4 (POCOP)(DMAP)] .

Treatment of trans -[Ir(H)(N) 2 (iPr)4 (POCOP)(DMAP)][BAr 4 f ] (2) with H 2 (1 bar) under ambient conditions (298 K) results in the formation of a trans -[Ir(H)(η 2 -H 2 ) (iPr)4 (POCOP)(DMAP)][BAr 4 f ] (3) complex. Complex 3 exhibits H-atom site exchange between the bound H 2 and the hydride ligands which are mutually trans to one another. A plausible mechanism of this exchange involves metal-ligand cooperativity as studied by computations.