Metallosalen covalent organic frameworks for heterogeneous catalysis

Abstract

Metallosalen covalent organic frameworks (M(salen)-COFs) have garnered significant attention as promising candidates for advanced heterogeneous catalysis, including organocatalysis, electrocatalysis, and photocatalysis, due to their unique structural advantages (combining molecules catalysts and crystalline porous materials) and tunable topological network. It is essential to provide a comprehensive overview of emerging designs of M(salen)-COFs and corresponding advances in this field. Herein, this review first summarizes the reported metallolinkers and the synthesis methods of M(salen)-COFs. In addition, the review enumerates the excellent M(salen)-COF based heterogeneous catalysts and discusses the fundamental mechanisms behind the outstanding heterogeneous catalytic performance of M(salen)-COFs. These mechanisms include the pore enrichment effect (enhancing local concentration within porous materials to promote catalytic reactions), the three-in-one strategy (integrating enrichment, reduction, and oxidation sites in one system), and the incorporation of a built-in electric field (implanting a built-in electric field in heterometallic phthalocyanine covalent organic frameworks). Furthermore, this review discusses the challenges and prospects related to M(salen)-COFs in heterogeneous catalysis.