Rapid Post-Synthetic Modification of Porous Coordination Cages with Copper-Catalyzed Click Chemistry

Abstract

Novel cobalt calixarene-capped and zirconium-based porous coordination cages were prepared with alkyne and azide functionality to leverage post-synthetic modification by click chemistry. While the calixarene-capped cages showed impressive stability when exposed to the most straightforward copper(I)- catalyzed alkyne–azide cycloaddition (CuAAC) reaction conditions with copper (II) sulfate and sodium ascorbate as the reducing agent, milder reaction conditions were necessary to perform analogous CuAAC reactions on zirconium-based cages. Reaction kinetics were monitored by IR spectroscopy, confirming rapid reaction times (< 3 hours).