Latest ArticlesAs antibiotic pollutants cannot be incompletely removed by conventional wastewater treatment plants, ultraviolet (UV) based advanced oxidation processes (AOPs) such as UV/persulfate (UV/PS) and UV/chlorine are increasingly concerned for the effective removal of antibiotics from wastewaters. However, the specific mechanisms involving degradation kinetics and transformation mechanisms are not well elucidated. Here we report a detailed examination of SO4•−/Cl•-mediated degradation kinetics, products, and toxicities of sulfathiazole (ST), sarafloxacin (SAR), and lomefloxacin (LOM) in the two processes. Both SO4•−/Cl•-mediated transformation kinetics were found to be dependent on pH (P < 0.05), which was attributed to the disparate reactivities of their individual dissociated forms. Based on competition kinetic experiments and matrix calculations, the cationic forms (H2ST+, H2SAR+, and H2LOM+) were more highly reactive towards SO4•− in most cases, while the neutral forms (e.g., HSAR0 and HLOM0) reacted the fastest with Cl• for the most of the antibiotics tested. Based on the identification of 31 key intermediates using tandem mass spectrometry, these reactions generated different products, of which the majority still retained the core chemical structure of the parent compounds. The corresponding diverse transformation pathways were proposed, involving S−N breaking, hydroxylation, defluorination, and chlorination reactions. Furthermore, the toxicity changes of their reaction solutions as well as the toxicity of each intermediate were evaluated by the vibrio fischeri and ECOSAR model, respectively. Many primary by-products were proven to be more toxic than the parent chemicals, raising the wider issue of extended potency for these compounds with regards to their ecotoxicity. These results have implications for assessing the degradative fate and risk of these chemicals during the AOPs.
Early recognition is key to improving the prognosis of ischemic stroke (IS), while available imaging methods tend to target events that have already undergone ischemia. A new method to detect early IS is urgently needed, as well as further study of its mechanisms. Viscosity and cysteine (Cys) levels of mitochondria have been associated with ferroptosis and IS. It is possible to identify IS and ferroptosis accurately and early by monitoring changes in mitochondrial Cys and viscosity simultaneously. In this work, a viscosity/Cys dual-responsive mitochondrial-targeted near-infrared (NIR) fluorescent probe (NVCP) was constructed for the precise tracking of IS using a two-dimensional design strategy. NVCP consists of a chromophore dyad containing diethylaminostyrene quinolinium rotor and chloro-sulfonylbenzoxadiazole (SBD-Cl) derivative with two easily distinguished emission bands (λem = 592 and 670 nm). NVCP performs the way of killing two birds with one stone, that is, the probe exhibits excellent selectivity and sensitivity for detecting viscosity and Cys in living cells with excellent biocompatibility and accurate mitochondrial targeting capability by dual channel imaging mode. In addition, NVCP recognized that the viscosity increases and Cys level decreases in cells when undergoing ferroptosis and oxygen-glucose deprivation (OGD) stress by confocal imaging, flow cytometry, and Western blot experiments. Treatment of ferroptosis inhibitors (ferrostatin-1 (Fer-1) and deferoxamine (DFO)) could reverse the variation tendency of viscosity and Cys. This is the first time that the relationship between ferroptosis and IS was identified through an analysis of Cys and viscosity. More importantly, the ischemic area was also instantly distinguished from normal tissues through fluorescence imaging of NVCP in vivo. The developed NIR dual-responsive probe NVCP toward viscosity and Cys could serve as a sensitive and reliable tool for tracking ferroptosis-related pathological processes during IS.
The asymmetric addition of aromatic organometallic compounds to the carbonyl group (C-3) of isatins, catalyzed by transition metals, has emerged as a remarkably efficient method for the synthesis of chiral 3-hydroxyoxindoles. Here, an exceptionally enantioselective approach was developed for the first time to achieve a catalytic NHK reaction of isatins with aromatic halides (both aryl and heteroaryl). Utilizing chiral cobalt complexes as catalysts, and the presence of a diboron reagent B2nep2 as both a reducing agent and determinant in enantiocontrol, has resulted in the triumphantly achieved synthesis of enantioenriched products. Compared to reported strategies, this approach exhibits remarkable compatibility with substrates bearing sensitive functional groups, such as halides and borate esters, while also eliminating the need for organometallic reagents as required in previous strategies. Through experimental investigations, the presence of aryl-cobalt species during the addition process was confirmed, rather than in-situ generation of an arylboron reagent. Furthermore, the successful attainment of the R absolute configuration through aryl addition was demonstrated.
As a versatile and environmentally benign oxidant, hydrogen peroxide (H2O2) is highly desired in sanitation, disinfection, environmental remediation, and the chemical industry. Compared with the conventional anthraquinone process, the electrosynthesis of H2O2 through the two-electron oxygen reduction reaction (2e− ORR) is an efficient, competitive, and promising avenue. Electrocatalysts and devices are two core factors in 2e− ORR, but the design principles of catalysts for different pH conditions and the development trends of relevant synthesis devices remain unclear. To this end, this review adopts a multiscale perspective to summarize recent advancements in the design principles, catalytic mechanisms, and application prospects of 2e− ORR catalysts, with a particular focus on the influence of pH conditions, aiming at providing guidance for the selective design of advanced 2e− ORR catalysts for highly-efficient H2O2 production. Moreover, in response to diverse on-site application demands, we elaborate on the evolution of H2O2 electrosynthesis devices, from rotating ring-disk electrodes and H-type cells to diverse flow-type cells. We elaborate on their characteristics and shortcomings, which can be beneficial for their further upgrades and customized applications. These insights may inspire the rational design of innovative catalysts and devices with high performance and wide serviceability for large-scale implementations.
Here we present a highly efficient protocol utilizing nickel-hydride hydrogen atom transfer catalysis for the regio- and enantioselective hydrofluorination of internal alkenes. This method efficiently assembles a wide array of enantioenriched β-fluoro amides with excellent regio- and enantioselectivity from internal unactivated alkenes. Mechanistic investigations suggest that this transformation proceeds via a NiH-hydrogen atom transfer to alkene, followed by a stereoselective fluorine atom transfer process. The weak coordination effect of the tethered amide group is identified as a crucial factor governing the observed regio- and enantioselectivity.
Combining cytotoxic drugs with tumor microenvironment (TME) modulator agents is an effective strategy to enhance anti-tumor effects. In this study, two natural anti-tumor active ingredients celastrol (CEL) and glycyrrhetinic acid (GA) were combined for tumor treatment. In order to ensure the precise co-delivery and controllable synchronous release of combined drugs to tumors, it is necessary to construct a suitable nano-drug delivery platform. Based on this, we coupled hyaluronic acid (HA) with CEL by amide reaction to obtain an amphiphilic polymer prodrug HA-SS-CEL, and GA was spontaneously loaded into polymer micelles by self-assembly to obtain G/HSSC-M. G/HSSC-M has ideal size distribution, redox-responsive synchronous drug release, enhanced tumor cell internalization and in vivo tumor targeting. Compared with free drugs, the construction of multifunctional polymer micelles makes G/HSSC-M show better anticancer effect at the same concentration, and can significantly inhibit the proliferation and migration of HepG2 and 4T1 cells. In the in vivo experiments, G/HSSC-M achieved a tumor inhibition rate as high as 75.12% in H22 tumor-bearing mice. The mechanism included regulation of M1/M2 macrophage polarization, inhibition of Janus kinase 1/signal transducer and activator of transcription 3 (JAK1/STAT3) signaling pathway, and remodeling of tumor blood vessels. Therefore, the development of prodrug micelles co-loaded with CEL and GA provides a promising drug co-delivery strategy for combined cancer therapy.
Nanobelts are a rapidly developing family of macrocycles with appealing features. However, their host-guest chemistry is currently limited to the recognition of fullerenes via π–π interactions. Herein, we report two heteroatom-bridged [8]cyclophenoxathiin nanobelts ([8]CP-Me and [8]CP) encapsulate corannulene (Cora) to form bowl-in-bowl supramolecular structures stabilized mainly through CH–π interactions in solid-state. The convex surface of corannulene is oriented towards the cavity due to geometry complementarity. The complex Cora⊂[8]CP exhibits a unique 2:2 capsule-like structure in crystal packing, in which corannulene adopts a concave-to-concave assembling fashion. This work enriches the molecular recognition of nanobelts and demonstrates that CH–π interactions can act as the main driving force for nanobelts host-guest complexes.
Humic acid (HA), as a represent of natural organic matter widely existing in water body, dose harm to water quality and human health; however, it was commonly treated as an environmental background substance while not targeted contaminant in advanced oxidation processes (AOPs). Herein, we investigated the removal of HA in the alkali-activated biochar (KBC)/peroxymonosulfate (PMS) system. The modification of the original biochar (BC) resulted in an increased adsorption capacity and catalytic activity due to the introduction of more micropores, mesopores, and oxygen-containing functional groups, particularly carbonyl groups. Mechanistic insights indicated that HA is primarily chemically adsorbed on the KBC surface, while singlet oxygen (1O2) produced by the PMS decomposition served as the major reactive species for the degradation of HA. An underlying synergistic adsorption and oxidation mechanism involving a local high concentration reaction region around the KBC interface was then proposed. This work not only provides a cost-effective solution for the elimination of HA but also advances our understanding of the nonradical oxidation at the biochar interface.
The chemo-, regio-, and enantio-controlled synthesis of P-chiral phosphines in a general and efficient manner remains a significant synthetic challenge. In this study, a Pd-catalyzed hydrofunctionalization is developed for the highly selective synthesis of P-stereogenic alkenylphosphinates and alkenylphosphine oxides via conjugate addition of enynes. Notably, this methodology is suitable for both phosphine oxide and phosphinate nucleophiles, providing a versatile approach for the construction of diverse P-chiral organophosphosphorus compound.
Bridged bicyclic cores have been recognized as valuable bioisosteres of benzene ring, which are of great value in medicinal chemistry. However, the development of fluorinated bicyclic skeletons, which encompass two privileged elements widely acknowledged for fine tuning the working effect of target molecules, are far less common. Herein, we present a general and practical synthesis of gem–difluorobicyclo[2.1.1]hexanes (diF-BCHs) from readily available difluorinated hexa-1,5-dienes through energy transfer photocatalysis. By taking advantage of an efficient Cope rearrangement, the preparation of both constitutional isomers of diF-BCHs is readily achieved under identical conditions. The operational simplicity, mild conditions and wide scope further highlight the potential application of this protocol. Moreover, computational studies indicated a positive effect of fluorine atoms in lowering either the triplet or FMO energies of the hexa-1,5-diene substrates, thus promoting the present photoinduced [2 + 2] cycloaddition.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
