Covalent organic frameworks (COFs), a fast-growing field in crystalline porous materials, have achieved tremendous success in structure development and application exploration over the past decade. The vast majority of COFs reported to date are designed according to the basic concept of reticular chemistry, which is rooted in the idea that building blocks are fully connected within the frameworks. We demonstrate here that sub-stoichiometric construction of 2D/3D COFs can be accomplished by the condensation of a hexagonal linker with 4-connected building units. It is worth noting that the partially connected frameworks were successfully reticulated for 3D COFs for the first time, representing the highest BET surface area among imine-linked 3D COFs to data. The unreacted benzaldehydes in COF frameworks can enhance C 2 H 2 and CO 2 adsorption capacity and selectivities between C 2 H 2 /CH 4 and C 2 H 2 /CO 2 for sub-stoichiometric 2D COFs, while the reserved benzaldehydes control the interpenetrated architectures for the 3D case, achieving a rare non-interpenetrated pts topology for 3D COFs. This work not only paves a new avenue to build new COFs and endows residual function groups with further applications but also prompts redetermination of reticular frameworks in highly connected and symmetrical COFs.

The use of computational modeling algorithms to guide the design of novel enzyme catalysts is a rapidly growing field. Force-field based methods have now been used to engineer both enzyme specificity and activity. However, the proportion of designed mutants with the intended function is often less than ten percent. One potential reason for this is that current force-field based approaches are trained on indirect measures of function rather than direct correlation to experimentally-determined functional effects of mutations. We hypothesize that this is partially due to the lack of data sets for which a large panel of enzyme variants has been produced, purified, and kinetically characterized. Here we report the kcat and KM values of 100 purified mutants of a glycoside hydrolase enzyme. We demonstrate the utility of this data set by using machine learning to train a new algorithm that enables prediction of each kinetic parameter based on readily-modeled structural features. The generated dataset and analyses carried out in this study not only provide insight into how this enzyme functions, they also provide a clear path forward for the improvement of computational enzyme redesign algorithms.

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As a clean and promising hydrogen production process, the electrochemical hydrogen evolution reaction (HER) is particularly important. However, its electrocatalytic activity is usually limited by the acid or base environment of the electrolyte. To achieve efficient conversion in energy storage, developing cost-effective nonprecious HER electrocatalysts at all pH values is highly required. Herein, defect-rich porous CoS 1.097 /MoS 2 hybrid microspheres are synthesized via a one-step sulfurization method. As expected, the optimal pH-universal CoS 1.097 /MoS 2 HER electrocatalyst shows overpotentials of 228, 249, and 341 mV at −10 mA cm −2 and small Tafel slopes of 59, 75, and 85 mV dec −1 in 0.5 M H 2 SO 4 , 1.0 M KOH, and 0.1 M PBS electrolyte, respectively. Furthermore, the CoS 1.097 /MoS 2 also presents outstanding HER catalytic stability in a 21 h stability test. The outstanding performance of CoS 1.097 /MoS 2 can be ascribed to the synergetic interplay of CoS 1.097 and MoS 2 , with abundant defects and a hierarchically ordered interconnected micro/mesoporous structure.

The discovery of metal–organic frameworks (MOFs) mimicking inorganic minerals with intricate topologies requires elaborate linker design guidelines. Herein, the concept of linker desymmetrization into the design of tetratopic linker based Zr‐MOFs is applied. A series of bent tetratopic linkers with various substituents are utilized to construct Zr‐MOFs with distinct cluster connectivities and topologies. For example, the assembly between a bent linker L‐SO2 with C2v symmetry and an 8‐connected Zr6 cluster leads to the formation of an scu topology, while another flu topology can be obtained by the combination of a novel 8‐connected Zr6 cluster and a bent linker L‐O with C1 symmetry. Further utilization of restricted bent linker [(L‐(CH3)6)] gives rise to a fascinating (4, 6)‐c cor net, originated from the corundum lattice, with an unprecedented 6‐c Zr6 cluster. In addition, the removal of toxic selenite ions in aqueous solution is performed by PCN‐903‐(CH3)6 which exhibits rapid and efficient detoxification. This work uncovers new structural opportunities for Zr‐MOFs via linker desymmetrization and provides novel design strategies for the discovery of sophisticated topologies for practical applications.

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Solid‐state transformations in metal–organic frameworks (MOFs) are important and have led to the creation of new MOF structures. Solid‐state transformations from interpenetrated to non‐interpenetrated networks involving rearrangement of secondary building units (SBUs) in a single‐crystal‐to‐single‐crystal (SCSC) fashion have not been explored to date. Herein, we report the sequential, thermally stimulated solid‐state transformations in a barium‐organic framework (UPC‐600). The two‐fold interpenetrated framework of UPC‐600 is converted at 373 K into UPC‐601, a non‐interpenetrated framework. This proceeds in a SCSC fashion and involves the rearrangement of two proximate rod‐shaped SBUs in different nets to generate a new rod‐shaped SBU. At 473 K, a continuous solid‐state transformation involving a second rearrangement occurred, UPC‐601 converted into UPC‐602 by the rearrangement of the 1D rod‐shaped SBU to a 2D layer SBU. This is the first example of such a thermally driven stepwise transformation involving simultaneous cleavage and regeneration of multiple bonds.