Bridge functionalized bis-N-heterocyclic carbene rhodium(I) complexes and their application in catalytic hydrosilylation

A series of chelating bridge functionalized bis-N-heterocyclic carbenes (NHC) complexes of rhodium (I) were prepared by reacting the corresponding imidazolium salts with [Rh(COD)Cl]2 in an in-situ reaction. For the N-methyl substituted complex with a PF6-anion an X-ray crystal structure was exemplary obtained. All complexes were spectroscopically characterized and tested for the hydrosilylation of acetophenone.

Symmetrically substituted bis-N-heterocyclic carbene rhodium (I) complexes with an –OH group attached to the bridging moiety were prepared, spectroscopically characterized and applied for catalytic hydrosilylation.Figure optionsDownload as PowerPoint slideResearch highlights
► Cationic Rh(I) complexes bearing chelating bis-NHCs catalyze the hydrosilylation of acetophenone with diphenylsilane.
► The nature of the wingtip moieties and the anion have an effect on the catalytic activity.
► The hydroxy group at the heterocycle backbone can be used for the catalyst immobilization.