Covalent organic frameworks (COFs) are promising candidates as heterogeneous photocatalysts because of their porosity and tunable light absorption. The photostability and charge separation of COFs are highly important to improve the efficiency of photocatalytic transformation. In this work, a fully conjugated donor–acceptor COF is constructed with a benzothiadiazole unit, which exhibits high stability and enhanced charge separation. The prepared COF can efficaciously produce superoxide radical anions under air and visible light, which mediate the photocatalytic oxidative amine coupling and cyclization of thioamide to 1,2,4-thiadiazole in moderate to high yield and high recyclability (18 examples). This study demonstrates the great capacity of fully conjugated COFs with a D–A structure for light-driven organic synthesis.

2D conjugated MOFs have attracted significant interests in recent years owing to their special structural features and promising physical and chemical properties. These intriguing attributes, to a large extent, stem from the nature of incorporated ligands. The available ligands for the construction of 2D conjugated MOFs are still limited, especially those that have heteroatoms included and exposed to the pores. In this work, we designed and synthesized a highly symmetric hexaazatrinaphthylene (HATNA)-based ligand with two different coordination sites. Through selective coordination, a highly crystalline and porous 2D conjugated copper metal-organic framework was constructed. Due to the synergic effects of HATNA and copper catecholate node, this HATNAbased 2D conjugated MOF can mediate the electrocatalytic reduction of CO 2 to methane with high selectivity of 78 % at high current density of 8.2 milliamperes per square centimetre (mA cm À2 ) for long durability over 12 hours.

We report on the fabrication of amphiphilic thermoresponsive diblock copolymer micelle-based multifunctional ratiometric fluorescent chemosensors for metal ions (Hg2+ and Cu2+), pH, and temperatures. A fluorescence resonance energy transfer (FRET) pair consisting of 4-(2-acryloyloxyethylamino)-7-nitro-2,1,3-benzoxadiazole (NBDAE) donor and rhodamine B-based potential acceptor (RhBHA) in the spirolactam form with pH and Hg2+(Cu2+)-reactive characteristics were respectively copolymerized into the hydrophobic PS and thermoresponsive PNIPAM block of P(St-co-NBDAE)-b-P(NIPAM-co-RhBHA) amphiphilic diblock copolymers, where PS and PNIPAM represent polystyrene and poly(N-isopropylacrylamide). In aqueous solution, the FRET pair-labeled diblock copolymer self-assembles into nanosized micelles with NBDAE moieties located in the micellar cores and RhBHA in the thermoresponsive coronas. Because of that Hg2+ ions and acidic pH can induce the transformation of RhBHA from the nonfluorescent spirolactam form to highly fluorescent acyclic form, and the FRET process between NBDAE and RhBHA moieties, located respectively within micellar cores and coronas, can be effectively switched on. Thus, these nanosized micelles can serve as excellent ratiometric fluorescent probes for Hg2+ ions and pH, accompanied by fluorometric transition from green to orange and colorimetric change from almost colorless to pink. At a micellar concentration of 0.05 g/L and 25 °C, the detection limit of Hg2+ ions can be down to ∼14.8 ppb. On the other hand, Cu2+ ions can quantitatively induce the ring-opening of RhBHA moieties and afford nonfluorescent residues, which can effectively quench the NBDAE emission. On the basis of the relative changes in NBDAE emission intensities, the Cu2+ detection limit can be down to ∼4.3 ppb. Most importantly, the spatial distance of the FRET pair can be facilely tuned via thermo-induced collapse of PNIPAM micellar coronas, which dramatically increase the FRET efficiency and enhance the pH detection sensitivity. This work represents a proof-of-concept example of amphiphilic block copolymer micelles-based multifunctional ratiometric fluorescent probes for two types of metal ions (Hg2+ and Cu2+), pH, and temperatures, which augurs well for their potential applications as nanocarriers with integrated functions such as imaging, sensing, and controlled-release of therapeutics.

Herein, two new classes of macrocyclic compounds, terphen[n]arenes (TPns) (n=3–6) and quaterphen[n]arenes (QPns) (n=3–6), were designed and synthesized by a one‐step condensation reaction in relatively high yields. They comprise 2,2′′‐dimethoxy terphenyl and 2,2′′′‐dimethoxy quaterphenyl monomers, respectively, linked by methylene bridges. Given their long and rigid monomers, TPns and QPns have much larger cavities and better self‐assembly properties than classic macrocycles. More interestingly, the cyclic pentamers and hexamers TP5, TP6, QP5, and QP6 formed supramolecular organogels, which were composed of interwoven fibers, nanosheets, or entangled macropore networks formed by multiple face‐to‐face and edge‐to‐face π⋅⋅⋅π stacking interactions. The xerogel materials effectively captured volatile iodine, not only in aqueous media but also in the gaseous state, and could be recycled multiple times without obvious loss in performance.