Latest ArticlesA porous lanthanum (La) carbonate-carbon composite (LaCC) was prepared by vacuum-freeze-drying and pyrolysis techniques to remove phosphorus (P) from wastewater. Using polyethylene glycol as a carbon skeleton template, and the organic ligands are removed during pyrolysis, resulting in the creation of many pore structures. The LaCC showed excellent P removal performance and selectivity over a wide pH range (3–10). It exhibited a rapid adsorption rate and could hold up to 119.5 mg P/g. Fixed-bed column experiments showed that under dynamic conditions, just 1 g of LaCC effectively treated 60 L of P-contaminated wastewater with an initial concentration of 2 mg/L, meeting the primary discharge standard of <0.5 mg/L according to the comprehensive sewage guidelines of China. Bacterial experiments showed that the LaCC could inhibit the growth of Escherichia coli, indicating that it has both P removal and bacterial inhibition effects, which can greatly improve the application range of adsorbents.
Electrocatalytic nitrate reduction reaction (NO3−RR) is a green and competitive method for removing nitrate from water, requiring highly active and long-term stable electrocatalysts. In this work, we report a Cu0 nanorod catalyst with disordered structure (re-Cu NRs), prepared by electrochemical in situ reconfiguration of copper-based nitrides (Cu3N NRs). The amorphous structure allows the exposure of abundant active sites to enhance the electrocatalytic activity because of the disordered atomic arrangement. At a potential of −1.2 V vs. Ag/AgCl, the re-Cu NRs catalyst achieved nearly 100% nitrate conversion within 120 min at a low nitrate concentration (50 mg/L), without the accumulation of nitrite. In-situ DEMS detection reveals that the NO3−RR on re-Cu NRs followed the pathway of *NO3−→ *NO2−→ *NO → *N → *NH → *NH2 → *NH3. Furthermore, combining this proposed pathway with electrochlorination could efficiently transform ammonia into harmless N2 (~99.41%). Theoretical calculations confirm that the amorphous structure on the surface of re-Cu NRs catalysts can facilitate strongly adsorbed nitrate, weaken the rate-determining step of *NH3 → NH3, and suppress hydrogen evolution reaction (HER). This study provides a new approach for designing efficient and stable amorphous catalysts for electrocatalytic nitrate reduction.
Mitochondria are crucial organelles responsible for maintaining cell growth, and their homeostasis is closely linked to pH regulation. Physiologically, mitochondria exhibit a weakly alkaline state (pH~8.0). However, when subjected to stress stimuli that cause damage, cells initiate the process of mitophagy, resulting in mitochondrial acidification. Therefore, monitoring changes in mitochondrial pH to comprehend the physiological processes associated with mitophagy is essential. In this study, we developed an asymmetric pentamethine cyanine dye Cy5.5-H-CyN as a probe for continuous monitoring of mitophagy in living cells. By incorporating an azaindole structure into the dye molecule, a ratiometric fluorescence response was achieved that is specifically responsive to pH variations while preserving its ability to target mitochondria and emit near-infrared fluorescence. Through various methods inducing mitophagy, Cy5.5-H-CyN was employed to determine mitochondrial pH quantitatively, demonstrating its suitability as an ideal probe for continuous monitoring of mitophagy in living cells.
A novel photocatalytic energy transfer-driven radical relay strategy has been introduced for the chemo- and regioselective 1, 4-difunctionalization of carbon-sulfur double bonds. This represents the first instance of radical-mediated dual-functionalization of X-Y type unsaturated bonds, enabling the synthesis of complex linear molecules with CO, CN, and C-S bonds in a single operation. The method surpasses traditional approaches by avoiding the need for thiourea intermediates and the harsh conditions typically associated with them. The developed strategy exemplifies versatility, being applicable to 1, 4-oxyamination, 1, 4-diamination, and 1, 4-sulfonamination reactions, and has demonstrated compatibility with over 60 different substrates. The research also elucidates the role of electronic complementarity between radicals and receptors in achieving high selectivity in 1, 4-difunctionalization reactions. This study significantly advances the field of bifunctionalization and remote difunctionalization reactions, with profound implications for the development of pharmaceuticals and materials science.
A renewable fluorescent material (G⊂CP5L) has been constructed via supramolecular assembly between a new derivative of pillararene, namely leggero pillar[5]arene, as the host molecule (CP5L) and a tetraphenylethylene (TPE)-based ditopic guest (G). This new material can simultaneously perform efficient detection and separation of silver(Ⅰ) from aqueous environments. Possessing an electron-rich cavity and two cytosine groups modified on both rims, CP5L functions as the host-guest binding site for G and offers exclusive coordination sites for further interaction with Ag+. Adding Ag+ to the system undergoes dramatic fluorescence enhancement due to the mechanism of supramolecular assembly-induced enhanced emission (SAIEE). This fluorescence enhancement allows for efficient and visualized detection following a "light-up" pattern, achieving a limit of detection (LOD) of 1.3 × 10–7 mol/L, which is fully in line with the World Health Organization's drinking water standard of 9 × 10–7 mol/L. In addition, G⊂CP5L also shows strong anti-interference capability against other cationic species. For the separation of Ag+ from aqueous systems, G⊂CP5L displays exceptional adsorption efficiency (97%) and reliable recovery performance, demonstrating excellent recyclability after five experimental cycles without compromising its adsorption activity
Three monomers, namely A2, B2, and GH, were designed and synthesized. By utilizing double host-guest interactions, the monomers A2+B2+GH underwent self-assembly to form a supramolecular linear polymer (SLP) at high concentrations. Long fibers could be pulled from the concentrated SLP solution. Upon the addition of PdCl2(PhCN)2 into the SLP solution, a structural transformation occurred from SLP to a supramolecular crosslinked polymer (SCP) through metal coordination interaction. This transformation induced fluorescence quenching, test paper strips for ion detection experiment confirmed that the SLP had good detection ability for Pd2+. Furthermore, the SCP underwent a transformation into a gel when the concentration exceeded 145 mmol/L. The SCP gel demonstrated sensitivity to different stimuli, such as K+ ions and changes in temperature, accompanied by a reversible transition between sol and gel states. Additionally, rheological analyses indicated that the gel possessed favorable self-healing properties.
Electrocatalysis for nitrate (NO3–) removal from wastewater faces the challenge of merging efficient reduction and high selectivity to nitrogen (N2) with economic viability in a durable catalyst. In this study, bimetallic PdCu/TiOx composite catalysts were synthesized with varying Pd and Cu ratios through electrochemical deposition on defective TiOx nanotube arrays. Denitrification experiments demonstrated that the Pd1Cu1/TiOx catalyst exhibited the highest NO3– removal rate (81.2%) and N2 selectivity (67.2%) among all tested catalysts. Leveraging the exceptional light-responsive property of TiOx, the introduction of light energy as an assisting factor in electrocatalysis further augmented the NO3– treatment rate, resulting in a higher NO3– removal rate of 95.1% and N2 selectivity of approximately 90%. Compared to individual electrocatalysis and photocatalysis systems, the overpotential for the catalytic interface active *H formation in the photo-assisted electrocatalysis system was remarkably reduced, thus accelerating electron migration and promoting NO3– reduction kinetics. Economic analysis revealed an energy consumption of 2.74 kWh/mol and a corresponding energy consumption per order (EEO) of 0.79 kWh/m3 for the Pd1Cu1/TiOx catalyst to reduce 25.2 mg/L of NO3–-N in water to N2, showcasing remarkable competitiveness and economic advantages over other water treatment technologies. This study developed the PdCu/TiOx electrocatalysts with high NO3– removal rates and N2 selectivity, particularly when combined with light energy, the efficiency and selectivity were significantly enhanced, offering a competitive and economically viable solution for wastewater treatment.
2-Azabicyclo[2.1.1]hexanes (aza-BCHs) are constrained pyrrolidine analogues with improved physicochemical characteristics in drug design. Here, we report a direct visible light-mediated photocycloaddition of 4-aza-coumarins with mono- or disubstituted bicyclo[1.1.0]butanes for synthesizing aza-BCHs without an external catalyst. The introduction of the ester group on 4-azacoumarin is critical for direct imine excitation and versatile synthetic utility. Preliminary mechanistic studies indicated that the reaction took place primarily at the triplet hypersurface.
A new oxidative N-heterocyclic carbene (NHC)-catalyzed high-order [7 + 3] annulation reaction of γ-indolyl phenols as 1, 7-dinucleophiles and α, β‐alkynals with the aid of Sc(OTf)3 is reported, enabling the highly regioselective access to unprecedented polyarene-fused ten-membered lactams bearing a bridged aryl-aryl-indole scaffold in moderate to good yields. This protocol demonstrates a broad substrate scope, good compatibility with substituents and complete regioselectivity, providing an organocatalytic modular synthetic strategy for creating medium-sized lactams.
The transition metal-catalyzed C-H activation have been considered as increasingly useful approach for installing new functional groups onto organic small molecules due to their high step- and atom-economy, the abundance of hydrocarbon compounds, and the potential for late-stage functionalization of complex organic molecules. The ortho- and meta-C-H activation and functionalization of aromatic compounds have been widely explored in recent years, however the distal para-C-H activation and functionalization has remained a significant challenge because of the difficulty in forming energetically favorable metallacyclic transition states. The utilization of appropriate directing groups or templates as well as the meticulous design of catalysts and ligands has proven to be effective in transition-metal-catalyzed remote para-C-H bonds activation and functionalization of aromatic compounds. This review aims to summarize the strategies for controlling para-selective C-H functionalization using the directing group, template engineering, and catalyst/ligand design under transition metals catalysis in recent years.
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