In Crystallo Hydrogenation of Nitrous Oxide Using a Rhodium(II) Hydride Complex

The stoichiometric and catalytic hydrogenation of nitrous oxide mediated by gas/solid reactions of rhodium(II) pincer complexes [Rh(PNP-tBu)X]+ (X = CH3, H, OH; PNP-tBu = 2,6-(tBu2PCH2)2C5H3N) is reported. A reaction sequence involving Rh(II)–CH3 → Rh(II)–H → Rh(II)–OH → Rh(II)–H bond interconversions has been structurally mapped out by single-crystal X-ray diffraction and verified by EPR spectroscopy. These rhodium(II) metalloradicals are sufficiently robust to catalyze the hydrogenation of nitrous oxide at room temperature with modest productivity (8.3 apparent turnovers). The relative rates of the stoichiometric transformations suggest that Rh–O bond hydrogenolysis is turnover-limiting.