This review illustrates molecular-scale confinement, containment, isolation, and related concepts to present MOF-centric catalysts and to realize desired chemical transformations.

Metal–organic frameworks (MOFs) are promising candidates for the catalytic hydrolysis of nerve agents and their simulants. Though highly efficient, bulk water and volatile bases are often required for hydrolysis with these MOF catalysts, preventing real-world implementation. Herein we report a generalizable and scalable approach for integrating MOFs and non-volatile polymeric bases onto textile fibers for nerve agent hydrolysis. Notably, the composite material showed similar reactivity under ambient conditions compared to the powder material in aqueous alkaline solution. This represents a critical step toward a unified strategy for nerve agent hydrolysis in practical settings, which can significantly reduce the dimensions of filters and increase the efficiency of protective suits.

The efficient removal, capture, and recycling of ammonia (NH3) constitutes a demanding process; thus, the development of competent adsorbent materials is highly desirable. The implementation of metal–organic frameworks (MOFs), known for their tunability and high porosity, has attracted much attention for NH3 adsorption studies. Here, we report three isoreticular porphyrin-based MOFs containing aluminum (Al-PMOF), gallium (Ga-PMOF), and indium (In-PMOF) rod secondary building units with Brønsted acidic bridging hydroxyl groups. NH3 sorption isotherms in Al-PMOF demonstrated reversibility in isotherms. In contrast, the slopes of the adsorption isotherms in Ga-PMOF and In-PMOF were much steeper than those of Al-PMOF in lower pressure regions, with a decrease of NH3 adsorbed amounts observed between first cycle and second cycle measurements. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) suggested that the strength of the Brønsted acidic −OH sites was controlled by the identity of the metal, which resulted in stronger interactions between ammonia and the framework in Ga-PMOF and In-PMOF compared to Al-PMOF.

A desirable feature of metal–organic frameworks (MOFs) is their well-defined structural periodicity and the presence of well-defined catalyst grafting sites (e.g., reactive −OH and −OH2 groups) that can support single-site heterogeneous catalysts. However, one should not overlook the potential role of residual organic moieties, specifically formate ions that can occupy the catalyst anchoring sites during MOF synthesis. Here we show how these residual formate species in a Zr-based MOF, NU-1000, critically alter the structure, redox capability, and catalytic activity of postsynthetically incorporated Cu­(II) ions. Single-crystal X-ray diffraction measurements established that there are two structurally distinct types of Cu­(II) ions in NU-1000: one type with residual formate and one without. In NU-1000 with formate, Cu­(II) solely binds to the node via the formate-unoccupied, bridging μ3–OH, whereas in the formate-free case, it displaces protons from two node hydroxo ligands and resides close to the terminal −OH2. Under an inert atmosphere, node-bound formate facilitates the unanticipated reduction of isolated Cu­(II) to nanoparticulate Cu(0)a behavior which is essentially absent in the formate-free analogue because no other sacrificial reductant is present. When the two MOFs were tested as benzyl alcohol oxidation catalysts, we observed that residual formate boosts the catalytic turnover frequency. Density functional calculations showed that node-bound formate acts as a sacrificial two-electron donor and assists in reducing Cu­(II) to Cu(0) by a nonradical pathway. The negative Gibbs free energy of reaction (ΔG) and enthalpy of reaction (ΔH) indicate that the reduction is thermodynamically favorable. The work presented here highlights how the often-neglected residual formate prevalent in nearly all zirconium-based MOFs can significantly modulate the properties of supported catalysts.