Rhodium(I) Ferrocenylcarbene Complexes: Synthesis, Structural Determination, Electrochemistry, and Application as Hydroformylation Catalyst Precursors

摘要

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 NH"Pd were prepared, and the electronic effects of coligands 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 coligands on the activity and regioselectivity of the catalysts evaluated. Finally, the stability of the Rh-C-carbene bond of complex 1 under hydroformylation conditions was confirmed with C-13 NMR experiments.