Institute of Chemistry, Academia Sinica^* Institute of Bioscience and Biotechnologym, National Taiwan Ocean University^**
○Shin-Guang Shyu^* Hsiu-Mei Lin^** Der-Lii Tzou^* Shequ-Wen Cheng^*

The complex Rh(PPh₃)₃Cl immobilized on MCM-41 modified with (OEt)₃Si(CH₂)₃PPh₂ results in a stable hydrogenation catalyst with turn over frequency (TOF) three times higher than that of Rh(PPh₃)₃Cl in the hydrogenation of cyclohexene. Powder X-ray, BET pore size measurement and solid state ²⁹Si NMR were used to characterize the morphology of the catalyst. Solid state ³¹P NMR and EXAFS analyses of Rh were carried out to investigate the structure of the immobilized Rh catalyst. EXAFS analyses show a Rh to Rh interaction at 3.0 Å indicating a possible dimmer structure without Rh-Rh metal-metal bonding. After hydrogenation, a Rh-Rh interaction at 2.6 Å was observed indicating the presence of a Rh-Rh metal-metal bonding.