Metal ion attachment in cavities of metal organic polyhedra to enhance framework robustness and catalytic performance

Abstract

Metal–organic polyhedra (MOPs) have attracted great attention in the past two decades, but a better robustness of the polyhedra and functionalization in the cage space are still challenging in this field. Metal ions attached in the cages not only help to support the pores, but also serve as functional sites. Herein, we successfully achieved control over whether hydrated copper ions enter the cages of molecular octahedra by partly replacing the auxiliary ligands on their paddle wheel clusters. The introduction of hydrated metal ions enhances the robustness of the MOP, and the MOP with a hydrated metal ion in its cage (compound 4) exhibit a higher BET surface area than the one without it (compound 2). The catalytic ability of compound 4 for methanolysis of styrene oxide is significantly improved, with a conversion rate increasing from 53% for compound 2 to 81%.