Supported N-heterocyclic carbene rhodium complexes as highly selective hydroformylation catalysts

New supported rhodium(I) catalyst precursors were obtained in reaction of [Rh(OMe)(cod)]2 with polymeric monoliths containing methyl-imidazolium moieties and applied in 1-hexene hydroformylation at 10 atm of CO/H2. Under solventless conditions with a small amount of P(OPh)3 as a modifying ligand, [P(OPh)3]/[Rh] = 2, ca. 80% of aldehydes with a high n/iso ratio of ca. 6 was obtained in eight successive runs. When P(OCH2CF3)3 was used instead of P(OPh)3, n/iso ratios up to 49.8 were obtained, however, the systems were active only in two subsequent reactions. With PPh3 as a modifying ligand, the yield of aldehydes decreased to ca. 20% already in the third run and n/iso was ca. 3.

Graphical abstractNew rhodium(I) N-heterocyclic carbene complexes supported on polymeric monoliths applied as catalyst precursors of 1-hexene hydroformylation at 10 atm of CO/H2 with a small amount of P(OPh)3 as a modifying ligand, produced ca. 80% of aldehydes with n/iso ratio of ca. 6 in eight successive runs.Figure optionsDownload full-size imageDownload as PowerPoint slide