A cage-on-MOF strategy to coordinatively functionalize mesoporous MOFs for manipulating selectivity in adsorption and catalysis

Abstract

Functionalizing porous materials with capping agents generates hybrid materials with enhanced properties, while the challenge is how to improve the selectivity and maintain the porosity of the parent framework. Herein, we developed a “Cage-on-MOF” strategy to tune the recognition and catalytic properties of MOFs without impairing their porosity. Two types of porous coordination cages (PCCs) of opposite charges containing secondary binding groups were developed to coordinatively functionalize two distinct porous MOFs, namely MOF@PCC nanocomposites. We demonstrated that the surface-capped PCCs can act as “modulators” to effectively tune the surface charge, stability, and adsorption behavior of different host MOF particles. More importantly, the MOF@PCCs can serve as selective heterogeneous catalysts for condensation reactions to achieve reversed product selectivity and excellent recyclability. This work sets the foundation for using molecular cages as porous surface-capping agents to functionalize and manipulate another porous material, without affecting the intrinsic properties of the parent framework.

Design and application of metal organic frameworks for heavy metals adsorption in water: a review

“…Strategically incorporated functional groups within the MOFs further entice these metal ions through electrostatic interactions, culminating in strong chemical bonds that lock them away. [118][119][120][121][122] This approach ensures both efficiency and selectivity in pollutant removal, contributing to cleaner and healthier water resources. By leveraging the unique design exibility of MOFs, researchers continuously rene these captivating materials, propelling them towards real-world applications in environmental remediation.…”

Interfacial Engineering of Heterogeneous Reactions for MOF‐on‐MOF Heterostructures

“…By precisely controlling reaction conditions, solvent composition, temperature, and other parameters, porous MOFs can be selectively grown on covalent organic frameworks (COFs), hydrogen-bonded organic frameworks (HOFs), or other templates to form composite structures, endowing the materials with enhanced functionalities and properties. [146][147][148][149][150][151][152]54] This template-directed synthesis method offers an effective pathway for designing and fabricating multifunctional materials.…”

Regulated Dual Defects of Bridging Organic and Terminal Inorganic Ligands in Iron‐based Metal‐Organic Framework Nodes for Efficient Photocatalytic Ammonia Synthesis

“…To address this issue, the most common strategy is to remove part or all these terminal inorganic ligands for formation of defective structures with exposed coordinatively unsaturated metal sites, which can be used as catalytic active centers to efficiently adsorb and activate catalytic substrate molecules. [33][34][35][36][37] Recently, the organic ligand defects, which are made through acid/base etching, ligand substitution and heating, [38][39][40][41][42] have been used to create porous structures or coordinatively unsaturated metal sites. It is deduced that if the above both types of defect structures coexist in a MOF with multi-nuclear metal-oxygen clusters, the coordination environment and electron characteristics of different unsaturated metal centers, which are created by bridging organic ligand defects and terminal inorganic ligand defects, will be significantly different from those of saturated counterparts.…”