Multicomponent reactions to access S-aryl dithiocarbamates via an electron donor-acceptor complex under open-to-air conditions.

A simple and efficient transition-metal/photocatalyst-free visible-light-driven one-pot three-component reaction between thianthrenium salts, carbon disulfide and amines under an air atmosphere for the preparation of biologically relevant S-aryl dithiocarbamates is developed. This methodology is robust and scalable, and exhibits a broad substrate scope and excellent functional group tolerance. Of note, a wide range of primary aliphatic amines bearing different groups are suitable for this strategy. The synthetic utility was further demonstrated by a two-step one-pot multi-component reaction and photo-flow decagram-scale synthesis. Preliminary mechanistic studies suggest that the association of the dithiocarbamate anion with thianthrenium salts formed an electron donor-acceptor complex, which upon excitation with visible light produced an aryl radical via single-electron transfer.

Fabrication of Azacrown Ether-Embedded Covalent Organic Frameworks for Enhanced Cathode Performance in Aqueous Ni-Zn Batteries.

Crown ethers (CEs), known for their exceptional host-guest complexation, offer potential as linkers in covalent organic frameworks (COFs) for enhanced performance in catalysis and host-guest binding. However, their highly flexible conformation and low symmetry limit the diversity of CE-derived COFs. Here, we introduce a novel C3-symmetrical azacrown ether (ACE) building block, tris(pyrido)[18]crown-6 (TPy18C6), for COF fabrication (ACE-COF-1 and ACE-COF-2) via reticular synthesis. This approach enables precise integration of CEs into COFs, enhancing Ni2+ ion immobilization while maintaining crystallinity. The resulting Ni2+-doped COFs (Ni@ACE-COF-1 and Ni@ACE-COF-2) exhibit high discharge capacity (up to 1.27 mAh ⋅ cm-2 at 8 mA ⋅ cm-2) and exceptional cycling stability (>1000 cycles) as cathode materials in aqueous alkaline nickel-zinc batteries. This study serves as an exemplar of the seamless integration of macrocyclic chemistry and reticular chemistry, laying the groundwork for extending the macrocyclic-synthon driven strategy to a diverse array of COF building blocks, ultimately yielding advanced materials tailored for specific applications.

Visible-Light-Irradiated Multicomponent Reactions of Aliphatic Amines, Propiolate Acid Esters, and CF3 SO2 Na for Accessing ß-CF3 Enamines.

A novel one-pot two-step multicomponent reaction has been achieved for the preparation of ß-CF3 enamines by using different aliphatic amines, propiolates, and CF3 SO2 Na as starting material. In this protocol, various aliphatic amines including primary amines, cyclic or acyclic secondary amines were demonstrated to be good coupling partners, and different ß-CF3 enamines were obtained in moderate to good yields. Among them, the primary aliphatic amines only gave pure (E)-ß-CF3 enamines as products. The synthetic utility of the MCRs strategy was further demonstrated by mild conditions, gram-scale synthesis and natural sunlight-induced protocol. Preliminary mechanistic studies suggest that this trifluoromethylation of C(sp2 )-H involves radical process.

Green One-Pot Syntheses of 2-Sulfoximidoyl-3,6-dibromo Indoles Using N-Br Sulfoximines as Both Brominating and Sulfoximinating Reagents.

A green one-pot 2,3,6-trifunctionalization of N-alkyl/aryl indoles was achieved by adding three equivalents of N-Br sulfoximine to the indole solution. A variety of 2-sulfoximidoyl-3,6-dibromo indoles were prepared with 38-94% yields using N-Br sulfoximines as both brominating and sulfoximinating reagents. Based on the results of controlled experiments, we propose that a radical substitution involving 3,6-dibromination and 2-sulfoximination occurs in the reaction process. This is first time that 2,3,6-trifunctionalization of indole in one pot has been achieved.

Induction of luteolin on postharvest color change and phenylpropanoid metabolism pathway in winter jujube fruit (Ziziphus jujuba Mill. cv. Dongzao).

The postharvest quality of winter jujubes is prone to deterioration, including inevitable pericarp reddening and rapid nutrient loss from the flesh, significantly impacting its edible quality and commercial value. As a crucial metabolic pathway in plants, phenylpropane metabolism not only regulates plant stress resistance but also closely relates to various coloration effects. In this study, we investigated the effects of luteolin solutions on postharvest color changes and phenylpropanoid metabolism in winter jujube. The results indicated that compared to the control group, winter jujube fruit treated with 200 mg L-1 luteolin exhibited improved quality indexes, increased antioxidant capacity (capability of eliminating ABTS and DPPH radicals), and higher activities of antioxidant enzymes(superoxide dismutase (SOD), and catalase (CAT)). This led to a reduction in the oxidation of phenolic substances in winter jujube. Furthermore, luteolin treatment inhibited phenylpropanoid metabolism by suppressing the activities of 4-Coumarate: coenzyme A ligase (4CL), phenylalanine ammonilyase (PAL), and cinnamate 4 hydroxylase (C4H), as well as the expression of ZjUFGT, ZjDFT, and ZjPAL genes. Consequently, anthocyanin and quercetin synthesis were limited while the degradation rate of chlorophyll and carotenoid synthesis were slowed down after luteolin treatment. This resulted in delayed reddening of winter jujube following luteolin treatment. In conclusion, luteolin exhibits potential application prospects as a preservative for inhibiting reddening and browning in winter jujubes.

Effects of ultrasonic-assisted natural deep eutectic solvent on the extraction rate, stability and antifungal ability of polyphenols from Cabernet Sauvignon seeds.

Ultrasonic-assisted extraction using a natural deep eutectic solvent (UAE-NADES) is an efficient method for extracting grape seed polyphenols (GSPs). In this study, response surface methodology was used to optimize the extraction of GSPs with UAE-NADES, and the theoretical extraction rate of GSPs was 139.014 mg GAE/g, the actual extraction rate was 135.78 ± 1.3 mg GAE/g. A pseudo-second-order kinetic extraction fitting was established to simulate the extraction process and mechanism (R2 > 0.99). Analysis of antioxidant capacity, Fourier-infrared spectroscopy and scanning electron microscopy revealed that UAE-NADES works synergetically to maintain the stability of extracted GSPs. The results of high-performance liquid chromatography showed that catechin (41.14 mg/g) is the main component of GSPs in the extract. The UAE-NADES extraction of GSPs can inhibit the growth of Alternaria alternata at 0.25 mg GAE/g, while the GSPs extracted by other methods can effectively inhibit the growth of Alternaria alternata at 0.35 mg GAE/g. Thus, this study demonstrates that UAE-NADES is a high-efficiency means of extracting GSPs and, in a wider sense, is a promising extraction technology for the green utilization of waste resources.

A π-extended molecular belt with selective binding capability for fullerene C70.

A molecular belt incorporating naphthalene moieties, featuring an ellipsoidal cavity, was precisely engineered through bottom-up synthesis. Its pre-arranged geometry exhibits excellent complementarity to fullerene C70, resulting in remarkable selective binding ability (K = 1.3 × 106 M-1) for C70 compared to C60 (K = 176 M-1), forming a 1 : 1 complex. This superiority was unequivocally demonstrated by the single crystal structure of the complex, which revealed outstanding concave-convex shape complementarity between the two components. This highlights the potential application of molecular belts in the purification and separation of fullerenes.

A compact chemically driven [2]catenane rotary motor operated through alternate pumping and discharging.

Here we present a compact and precise [2]catenane rotary motor that functions with a single recognition site, capable of achieving a 360° directional rotation powered by chemical fuels. The motor is propelled by an acid-base fueled benzimidazolium pumping cassette and deemed the smallest (molecular weight ∼ 994 Da) catenane rotary motor to date. It can effectively undergo a 180° rotation by transitioning the [24]crown-6 ether (24C6) from the benzimidazolium site to the less favorable alkyl moiety through sequential deprotonation, slipping, and re-protonation operations, generating a meta stable co-conformer. Subsequently, a discharging phase, triggered by de-benzylation and re-benzylation, facilitates the other half-rotation of the motor, returning the 24C6 to its initial position and completing the full directional rotation of the [2]catenane rotary motor within 18 hours. The precision of the motor's operation enables further advances in artificial molecular machines.