16-Electron, non-π-stabilized Ir(H)2(H2)(PBu2tPh)2+ and 18-electron Ir(H)2(H2)2(PBu2tPh)2+: fluxionality and H/D exchange as independent processes

Variable-temperature 1H NMR studies and abinitio (B3LYP) calculations have revealed hydride site exchange in [Ir(H)2(H2)(PBu2tPh)2][BAr4′] [Ar′=C6H3(CF3)2-3,5] as well as fluxional and HD formation processes in [Ir(H)2(H2)2(PBu2tPh)2][BAr4′] that occur via independent mechanisms.