Covalent post-synthetic modification of metal-organic frameworks: A strategy for designing heterogeneous catalysts

Covalent post-synthetic modification (PSM) represents a robust and irreversible strategy for precisely engineering the chemical functionality of metal–organic frameworks (MOFs) without compromising their structural integrity or porosity. This review surveys recent developments in covalent PSM approaches that enhance catalytic performance by introducing diverse functional groups—such as amines, carboxylic acids, sulfonic acids, phosphonic acids, imines, and guanidines—onto MOF organic linkers. These modifications enable fine-tuning of active site distribution, electronic environments, and acid–base properties, thereby facilitating cooperative and multifunctional catalysis. Through detailed analysis of structure–activity relationships and representative catalytic systems, covalent PSM is established as a powerful strategy for designing efficient, selective, and recyclable MOF-based heterogeneous catalysts applicable to a broad range of organic transformations.