Highly Selective Enamination of β-ketoesters Catalyzed by Interlocked [Cu 8 ] and [Cu 18 ] Nanocages.

Interlocking cages are of great interest due to their fascinating structures and potential applications. However, the interlocking of different cages has not been previously reported. Herein, quadruply interlocked [Cu-8] and [Cu-18] nanocages have been constructed and structurally characterized in cationic metal-organic framework {[(CuCu4II)-Cu-I(XN)(4)(PTA)(4)(H2O)(4)]0.5 SO4.5 H2O.EtOH}(n) (1). 1 can trap the anionic pollutant CrO42- and the radioactive-contaminant simulant ReO4- with an uptake capacity of 83.2 and 218 mg g(-1), respectively. Catalytic investigations reveal 1 is an efficient heterogeneous catalyst for the enamination of ethyl acetoacetate with aniline and the turnover frequency (TOF) can reach a record value of 4000 h(-1). More importantly, 1 represents the first of a catalyst of enamination to exhibit excellent size selectivity on different substrates. The robust catalyst can be reused at least ten times without obvious loss in catalytic activity.