Surface charges of porous coordination cage tune the catalytic reactivity of Knoevenagel condensation

Abstract

Catalytic reactions always accompany steric and electronic effects. Due to the modulated structure and functionality, the surface charge of porous coordination cage can be tuned under the same topology. This provides a straightforward way to investigate the steric and electronic effects by using cage catalysts. Herein, we prepared two cages with 24- negative surface charge and zero surface charge and applied them in guest encapsulation and Knoevenagel condensation. The high anionic cage shows considerably higher adsorption kinetic for positive guests and much-improved reactivity in the catalytic reaction when comparing to the neutral counterpart. The negative charge was proved to be the dominant factor for the much-improved catalytic reactivity, rather than the cage structure. This finding provides new thoughts for design a suitable platform to investigate the individual impact factors for the catalytic reactions.