Enzymatic catalysis has fueled considerable interest from chemists due to its high efficiency and selectivity. However, the structural complexity and vulnerability hamper the application potentials of enzymes. Driven by the practical demand for chemical conversion, there is a long-sought quest for bioinspired catalysts reproducing and even surpassing the functions of natural enzymes. As nanoporous materials with high surface areas and crystallinity, metal−organic frameworks (MOFs) represent an exquisite case of how natural enzymes and their active sites are integrated into porous solids, affording bioinspired heterogeneous catalysts with superior stability and customizable structures. In this review, we comprehensively summarize the advances of bioinspired MOFs for catalysis, discuss the design principle of various MOF-based catalysts, such as MOF−enzyme composites and MOFs embedded with active sites, and explore the utility of these catalysts in different reactions. The advantages of MOFs as enzyme mimetics are also highlighted, including confinement, templating effects, and functionality, in comparison with homogeneous supramolecular catalysts. A perspective is provided to discuss potential solutions addressing current challenges in MOF catalysis.

As water scarcity becomes a pending global issue, hygroscopic materials prove a significant solution. Thus, there is a good cause following the structure–performance relationship to review the recent development of hygroscopic materials and provide inspirational insight into creative materials. Herein, traditional hygroscopic materials, crystalline frameworks, polymers, and composite materials are reviewed. The similarity in working conditions of water harvesting and carbon capture makes simultaneously addressing water shortages and reduction of greenhouse effects possible. Concurrent water harvesting and carbon capture is likely to become a future challenge. Therefore, an emphasis is laid on metal–organic frameworks (MOFs) for their excellent performance in water and CO2 adsorption, and representative role of micro‐ and mesoporous materials. Herein, the water adsorption mechanisms of MOFs are summarized, followed by a review of MOF's water stability, with a highlight on the emerging machine learning (ML) technique to predict MOF water stability and water uptake. Recent advances in the mechanistic elaboration of moisture's effects on CO2 adsorption are reviewed. This review summarizes recent advances in water–harvesting porous materials with special attention on MOFs and expects to direct researchers’ attention into the topic of concurrent water harvesting and carbon capture as a future challenge.

Oxidative stress is one of the hallmarks of ischemic stroke. Catalase-based (CAT) biomimetic complexes are emerging as promising therapeutic candidates that are expected to act as neuroprotectants for ischemic stroke by decreasing the damaging effects from H2O2. Unfortunately, these molecules result in the unwanted production of the harmful hydroxyl radical, HO•. Here, we report a series of salen-based tri-manganese (Mn­(III)) metallocryptands (1–3) that function as catalase biomimetics. These cage-like molecules contain a unique “active site” with three Mn centers in close proximity, an arrangement designed to facilitate metal cooperativity for the effective dismutation of H2O2 with minimal HO• production. In fact, significantly greater oxygen production is seen for 1–3 as compared to the monomeric Mn­(Salen) complex, 1c. The most promising system, 1, was studied in further detail and found to confer a greater therapeutic benefit both in vitro and in vivo than the monomeric control system, 1c, as evident from inter alia studies involving a rat model of ischemic stroke damage and supporting histological analyses. We thus believe that metallocryptand 1 and its analogues represent a new and seemingly promising strategy for treating oxidative stress related disorders.

Mimicking the active site and the substrate binding cavity of the enzyme to achieve specificity in catalytic reactions is an essential challenge. Herein, porous coordination cages (PCCs) with intrinsic cavities and tunable metal centers have proved the regulation of reactive oxygen species (ROS) generating pathways as evidenced by multiple photo-induced oxidations. Remarkably, in the presence of the Zn 4 -μ 4 -O center, PCC converted dioxygen molecules from triplet to singlet excitons, whereas the Ni 4 -μ 4 -O center promoted the efficient dissociation of electrons and holes to conduct electron transfer towards substrates. Accordingly, the distinct ROS generation behavior of PCC-6-Zn and PCC-6-Ni enables the conversion of O 2 to 1 O 2 and O 2 *À , respectively. In contrast, the Co 4 -μ 4 -O center combined the 1 O 2 and O 2 *Àtogether to generate carbonyl radicals, which in turn reacted with the oxygen molecules. Harnessing the three oxygen activation pathways, PCC-6-M (M = Zn/Ni/Co) display specific catalytic activities in thioanisole oxidation (PCC-6-Zn), benzylamine coupling (PCC-6-Ni), and aldehyde autoxidation (PCC-6-Co). This work not only provides fundamental insights into the regulation of ROS generation by a supramolecular catalyst but also demonstrates a rare example of achieving reaction specificity through mimicking natural enzymes by PCCs.