Zintl cluster supported low coordinate Rh(i) centers for catalytic H/D exchange between H(2) and D(2)

Ligand exchange reactions of [Rh(COD){η(4)-Ge(9)(Hyp)(3)}] with L-type nucleophiles such as PMe(3), PPh(3), IMe(4) (IMe(4) = 1,3,4,5-tetramethylimidazol-2-ylidene) or [W(Cp)(2)H(2)] result in the displacement of the COD ligand to afford clusters with coordinatively unsaturated trigonal pyramidal rhodium(i) centers [Rh(L){η(3)-Ge(9)(Hyp)(3)}]. These species can be readily protonated allowing access to cationic rhodium–hydride complexes, e.g. [RhH(PPh(3)){η(3)-Ge(9)(Hyp)(3)}](+). These clusters act as catalysts in H/D exchange between H(2) and D(2) and alkene isomerisation, thereby illustrating that metal-functionalized Zintl clusters are active in both H–H and C–H bond activation processes. The mechanism of H/D exchange was probed using parahydrogen induced polarization experiments.