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Due to the high surface area and uniform porosity of covalent organic frameworks (COFs), they exhibit superior properties in capturing and detecting even trace amounts of gases in the air. However, the COFs materials that possess dual detected functionality are still less reported. Here, an imine‐based COF containing thiophene as a donor and triazine as an acceptor to form spatial‐distribution‐defined D‐A structures was prepared. D‐A system between thiophene and triazine facilitates the charge transfer process during the protonation process of the imine and the triazine units. The obtained COF exhibits simultaneous sensing ability toward both acidic and alkaline vapors with obvious colorimetric sensing functionality. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: This review presents a comprehensive examination of fully conjugated covalent organic frameworks (COFs), which constitute an emerging class of porous materials with immense potential for diverse applications. This article focuses on diversified fully conjugated COFs, including sp2 carbon‐carbon linkages, pyrazine linkages, benzobisoxazole linkages, dioxin linkages, β‐aminoalkenone linkages, etc. The synthesis techniques and structural attributes of these COFs are expounded upon in great detail, along with their potential applications in various fields. The review thus provides a valuable resource for researchers keen on delving into the synthesis and applications of fully conjugated COFs, thereby highlighting their potential for developing novel functional materials with distinctive properties. [ABSTRACT FROM AUTHOR]

Utilizing weak interactions to effectively recover and separate precious metals in solution is of great importance but the practice remains a challenge. Herein, we report a novel strategy to achieve precise recognition and separation of gold by regulating the hydrogen‐bond (H‐bond) nanotrap within the pore of covalent organic frameworks (COFs). It is found that both COF‐HNU25 and COF‐HNU26 can efficiently capture AuIII with fast kinetics, high selectivity, and uptake capacity. In particular, the COF‐HNU25 with the high density of H‐bond nanotraps exhibits an excellent gold uptake capacity of 1725 mg g−1, which is significantly higher than that (219 mg g−1) of its isostructural COF (COF‐42) without H‐bond nanostrap in the pores. Importantly, the uptake capacity is strongly correlated to the number of H‐bonds between phenolic OH in the COF and [AuCl4]− in water, and multiple H‐bond interactions are the key driving force for the excellent gold recovery and reusability of the adsorbent. [ABSTRACT FROM AUTHOR]

In the context of the energy crisis and global warming, developing clean and sustainable energy is receiving increasing attention. Photocatalytic processes including water splitting, CO2 reduction, coenzyme regeneration, etc., provide ideal ways to utilize renewable solar resources. The photocatalyst plays a central role in photocatalytic processes. Organic porous polymers have recently gained extensive attention in photocatalysis. Covalent organic frameworks (COFs), as one of the organic porous polymers, have the characteristics of high crystallinity, porosity, and structural designability that make them perfect platforms for photocatalysis. In this minireview, the recent progress of 2D COFs as photocatalysts is summarized including the recent work. The synthesis of the diversified structures of the COFs including the different linkages is first introduced. Then, the photocatalytic applications of the 2D COFs including photocatalytic hydrogen evolution, CO2 conversion, coenzyme regeneration, and other traditional organic reaction are then discussed. Finally, conclusions and prospects are provided in the last section. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Covalent organic frameworks (COFs) with good chemical stability coupled with extended‐conjugation structures are highly preferable. Herein, a fully‐conjugated and chemically stable two‐dimensional COF was synthesized by a one‐pot, three‐components synthesis through a successful conversion of amine, aldehyde, and alkyne groups into the quinoline units as linkages with B(C6F5)3 serving as a Lewis acid catalyst, whilst 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) was employed as an oxidant. The obtained fully conjugated 2D COF shows excellent stability in acid or base. [ABSTRACT FROM AUTHOR]

The synthesis of fully conjugated sp2‐carbon covalent organic frameworks (COF) is extremely challenging given the difficulty of the formation of very stable carbon‐carbon double bonds (‐C=C‐). Here, we report the successful preparation of a 2D COF (TP‐COF) based on triazine as central planar units bridged by sp2‐carbon linkers through the ‐C=C‐ condensation reaction. High‐resolution‐transmission electron microscopy (HRTEM) clearly confirmed the tessellated hexagonal pore structure with a pore center‐to‐center distance of 2 nm. Powder X‐ray diffraction (PXRD) together with structural simulations revealed an AA stacking mode of the obtained layered structure. TP‐COF turned out to be an excellent semiconductor material with a LUMO energy of −3.23 eV and a band gap of 2.36 eV. Excitingly, this novel sp2‐carbon conjugated TP‐COF exhibited unprecedented coenzyme regeneration efficiency and can significantly boost the coenzyme‐assisted synthesis of l‐glutamate to a record‐breaking 97 % yield within 12 minutes. Art imitates life: A 2D conjugated covalent organic framework (COF) based on triazine as a central planar unit bridged by sp2‐carbon linkers was constructed through the ‐C=C‐ condensation reaction. The COF can be used as an artificial photosystem I and shows an excellent coenzyme‐regeneration efficiency. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are a family of promising membrane materials because of their intrinsic pores with uniform size, tunable functionalities, and high stability. Especially, two-dimensional (2D) COFs can be exfoliated into single- or few-layered nanosheets and restacked into molecular sieving membranes through controlling restacking modes and thickness. However, traditional methods mainly rely on increasing the thickness (vertical restacking control) to achieve high separation selectivity but with compromised permeance. Herein, the fabrication of ultrathin COF (CTF-BTD) membranes through the restacking of the nanosheets with the aid of introducing thermal perturbation is reported, i.e. , a heating vacuum filtration method to optimize the relative displacement of nanosheets without sacrificing thickness control. As a result, a membrane exhibits high H 2 permeance (655.6 GPU) and H 2 /CO 2 selectivity (43.1) for CO 2 pre-combustion capture, which are superior than those of the membranes prepared at room temperature. This work realizes an enhanced separation performance through the control of restacking modes, which will inspire the optimization of other membrane architectures. [Display omitted] • Restacking control was realized in the 2D COF nanosheet membranes. • Heating vacuum filtration optimize the restacking microstructure. • Optimized COF membranes displayed enhanced H 2 /CO 2 separation. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: This review presents a comprehensive examination of fully conjugated covalent organic frameworks (COFs), which constitute an emerging class of porous materials with immense potential for diverse applications. This article focuses on diversified fully conjugated COFs, including sp2 carbon‐carbon linkages, pyrazine linkages, benzobisoxazole linkages, dioxin linkages, β‐aminoalkenone linkages, etc. The synthesis techniques and structural attributes of these COFs are expounded upon in great detail, along with their potential applications in various fields. The review thus provides a valuable resource for researchers keen on delving into the synthesis and applications of fully conjugated COFs, thereby highlighting their potential for developing novel functional materials with distinctive properties. [ABSTRACT FROM AUTHOR]