Rhodium(I) ferrocenylcarbene complexes : synthesis, structural determination electrochemistry and application as hydroformylation catalyst precursors

Abstract

New examples of the rare class of rhodium(I) ferrocenyl Fischer carbene complexes 1–8, [Rh(LL)Cl{C(XR)Fc}] [LL = cod, (CO)2, (CO, PR3) (R = Ph, Cy or OPh) and (CO, AsPh3); XR=OEt or NHnPr] were prepared, and the electronic effects of co-ligands and alkoxy vs. aminocarbene substituents were investigated by spectroscopic and electrochemical methods. The molecular structures of complexes 1, 2 and 4–6 were confirmed by single crystal X-ray diffraction. The use of the complexes 1–8 as homogeneous catalysts for the hydroformylation of 1-octene was demonstrated, and the influence of the carbene substituents and co-ligands on the activity and regioselectivity of the catalysis evaluated. Finally, the stability of the Rh-Ccarbene bond of complex 1 under hydroformylation conditions was confirmed with 13C NMR experiments.