Highly Selective Enamination of β-ketoesters Catalyzed by Interlocked [Cu8 ] and [Cu18 ] 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 [Cu8 ] and [Cu18 ] nanocages have been constructed and structurally characterized in cationic metal-organic framework {[CuI Cu4 II (XN)4 (PTA)4 (H2 O)4 ]0.5 SO4 ⋅5 H2 O⋅EtOH}n (1). 1 can trap the anionic pollutant CrO4 2- 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.