One of the most pressing environmental concerns of our age is the escalating level of atmospheric CO . Intensive efforts have been made to investigate advanced porous materials, especially porous organic polymers (POPs), as one type of the most promising candidates for carbon capture due to their extremely high porosity, structural diversity, and physicochemical stability. This review provides a critical and in-depth analysis of recent POP research as it pertains to carbon capture. The definitions and terminologies commonly used to evaluate the performance of POPs for carbon capture, including CO capacity, enthalpy, selectivity, and regeneration strategies, are summarized. A detailed correlation study between the structural and chemical features of POPs and their adsorption capacities is discussed, mainly focusing on the physical interactions and chemical reactions. Finally, a concise outlook for utilizing POPs for carbon capture is discussed, noting areas in which further work is needed to develop the next-generation POPs for practical applications.

This review summarizes recent developments of coordination cages catalysis across three key approaches: (1) cavity promoted reactions, (2) embedding of active sites in the structure of the cage, and (3) encapsulation of catalysts within the cage.

Stimuli-responsive metal-organic polyhedra (srMOPs) functionalized with azobenzene showed UV-irradiation-induced isomerization from the insoluble trans-srMOP to the soluble cis-srMOP, whereas irradiation with blue light reversed this process. Guest molecules were trapped and released upon cis-to-trans and trans-to-cis isomerization of the srMOPs, respectively. This study provides a new direction in the ever-diversifying field of MOPs, while laying the groundwork for a new class of optically responsive materials.

Herein we report for the first time the synthesis of Cr(II)-based metal-organic polyhedra (MOPs) and the characterization of their porosities. Unlike the isostructural Cu(II)- or Mo(II)-based MOPs, Cr(II)-based MOPs show unusually high gas uptakes and surface areas. The combination of comparatively robust dichromium paddlewheel units (Cr units), cage symmetries, and packing motifs enable these materials to achieve Brunauer-Emmett-Teller surface areas of up to 1000 m/g. Reducing the aggregation of the Cr(II)-based MOPs upon activation makes their pores more accessible than their Cu(II) or Mo(II) counterparts. Further comparisons of surface areas on a molar (m/mol cage) rather than gravimetric (m/g) basis is proposed as a rational method of comparing members of a family of related molecular materials.

Adsorbents for CO2 capture need to demonstrate efficient release. Light-induced swing adsorption (LISA) is an attractive new method to release captured CO2 that utilizes solar energy rather than electricity. MOFs, which can be tailored for use in LISA owing to their chemical functionality, are often unstable in moist atmospheres, precluding their use. A MOF is used that can release large quantities of CO2 via LISA and is resistant to moisture across a large pH range. PCN-250 undergoes LISA, with UV flux regulating the CO2 desorption capacity. Furthermore, under UV light, the azo residues within PCN-250 have constrained, local, structural flexibility. This is dynamic, rapidly switching back to the native state. Reusability tests demonstrate a 7.3 % and 4.9 % loss in both adsorption and LISA capacity after exposure to water for five cycles. These minimal changes confirm the structural robustness of PCN-250 and its great potential for triggered release applications.