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

Ligand exchange reactions of [Rh(COD){η-Ge(Hyp)}] with L-type nucleophiles such as PMe, PPh, IMe (IMe = 1,3,4,5-tetramethylimidazol-2-ylidene) or [W(Cp)H] result in the displacement of the COD ligand to afford clusters with coordinatively unsaturated trigonal pyramidal rhodium(i) centers [Rh(L){η-Ge(Hyp)}]. These species can be readily protonated allowing access to cationic rhodium-hydride complexes, [RhH(PPh){η-Ge(Hyp)}]. These clusters act as catalysts in H/D exchange between H and D 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 hydrogen induced polarization experiments.