Toward Homogenization of Heterogeneous Metal Nanoparticle Catalysts with Enhanced Catalytic Performance: Soluble Porous Organic Cage as a Stabilizer and Homogenizer.

Organic molecular cage (CC3-R) with intrinsically porous skeleton is used as a support for immobilizing Rh nanoparticles (NPs) in an ultrasmall size of ∼1.1 nm for the first time. The CC3-R with the unique characteristic of high solubility can be utilized to homogenize the heterogeneous catalyst in solution. The obtained homogenized heterogeneous catalyst Rh/CC3-R-homo exhibits significantly enhanced catalytic performance toward various liquid-phase catalytic reactions, as compared with the heterogeneous counterpart Rh/CC3-R-hetero. Moreover, Rh/CC3-R-homo shows excellent durability and recyclability. The advantage of combining homogeneous and heterogeneous catalysts is likely to be beneficial for many applications.