Latest ArticlesLate-stage modification of complex molecules via site-selective hydrodefluorination is a challenging endeavor. The selective activation of carbon-fluorine (C–F) bonds in the presence of multiple C–F bonds is of importance in organic synthesis and drug discovery. Herein, we describe the activation of C-F bonds via multiphoton photoredox catalysis to selectively produces a series of hydrodefluorinated compounds by simply tuning the reaction conditions. Moreover, this protocol was successfully applied to the late-stage functionalization of different drug-derivatives and the corresponding mono-, di-, and tri-defluorinated products were obtained in good to excellent yields. A detailed mechanistic investigation provides insight into the unprecedented hydrodefluorination pathway.
Excited-state intramolecular proton-transfer (ESIPT) based fluorescence probes are particularly attractive due to their unique properties including environmental sensitivity, a large Stokes shift, and potential for ratiometric sensing. In general, ESIPT-based fluorophore incorporates an intramolecular hydrogen bonding interaction between a hydrogen bond donor (–OH and NH2 are common) and a hydrogen bond acceptor (C=N and C=O). More, protection–deprotection of hydroxyl group as hydrogen bond donor could induce an off-on switch of ESIPT-based emission. Therefore, protection–deprotection of hydroxyl group has been the widely used strategy to design fluorescent probes, where the potential key issue is selecting a protective group that can specifically leave in the presence of the target analyte. In this review, we mainly summarize the specific protecting groups (sites) and deprotection mechanisms for biologically important species (including reactive sulfur species (RSS), reactive oxygen species (ROS), enzymes, etc.), and analyze the advantages and disadvantages of different protection mechanisms from some aspects including probe stability, selectivity, response rate and assay system, etc. Based on the aforementioned, we further point out the current challenges and the potential future direction for developing ESIPT-based probes.
Colorectal cancer (CRC) is one of the most prevalent malignant tumors worldwide, exhibiting high morbidity and mortality. Lack of efficient tools for early diagnosis and surgical resection guidance of CRC have been a serious threat to the long-term survival rate of the CRC patients. Recent studies have shown that relative higher viscosity was presented in tumor cells compared to that in normal cells, leading to viscosity as a potential biomarker for CRC. Herein, we reported the development of a series of novel viscosity-sensitive and mitochondria-specific fluorescent probes (HTB, HTI, and HTP) for CRC detection. Among them, HTB showed high sensitivity, minimal background interference, low cytotoxicity, and significant viscous response capability, making it an ideal tool for distinguishing colorectal tumor cells from normal cells. Importantly, we have successfully utilized HTB to visualize in a CRC-cells-derived xenograft (CDX) model, enriching its medical imaging capacity, which laid a foundation for further clinical translational application.
Nor-seco-cucurbit[10]uril (ns-CB[10]) is a kinetic product with unique structure. The single bridged methylene in its structure makes the molecular cavity of ns-CB[10] more deformable when compared to ordinary cucurbit[n]uril, reducing its structural stability. Repeated experiments showed that ns-CB[10] gradually cracks in an acidic solution and changes the specificity of cucurbit[5]uril (CB[5]) and cucurbit[8]uril (CB[8]) under more robust acidic solutions and when heated. A series of experiments were designed to study the transformation behavior of ns-CB[10]. It was found that the concentration of ns-CB[10] was correlated with the content distribution of CB[5] and CB[8]. This study explores the influencing factors and mechanisms of the transformation of ns-CB[10] to CB[5] and CB[8]. The results are of great significance for the application of ns-CB[10], understanding the formation mechanism of cucurbit[n]urils. Furthermore, it provides a new pathway for synthesizing new cucurbit[n]urils.
The first synthesis of flavanostilbenes with a 2-cyclohepten-1-one core was carried out by applying an effective strategy in three steps from abundant polymerized flavanol resources. A key regio- and stereoselective Cu-mediated [5 + 2] cycloaddition/decarboxylation cascade was explored and applied without the use of protecting groups, and water as an environmentally friendly solvent contributed to the cascade. The intramolecular [5 + 2] cycloaddition mechanism, involving oxidation and dearomatization of the flavanol unit as a diene, was proposed and supported by the synthesis of the intermediate. The regioselectivity of the cyclization was found to be dependent on the substitution effects of the stilbene units by the exploration of substrate scope.
Gold-catalyzed amination reactions based on azides via α-imino gold carbene intermediates have attracted extensive attention in the past decades because this methodology leads to the facile and efficient construction of synthetically useful N-containing molecules, especially valuable N-heterocycles. However, successful examples of intermolecular generation of α-imino gold carbenes by using azides as amination reagents are rarely explored probably due to the weak nucleophilicity of azides. Herein, we disclose an efficient gold-catalyzed intermolecular aminative cyclopropanation of ynamides with the allyl azides, enabling flexible synthesis of a wide range of valuable 3-azabicyclo[3.1.0]hex-2-ene derivatives in good to excellent yields with excellent diastereoselectivities. Importantly, this protocol represents the first use of allyl azide as an efficient amination reagent in gold-catalyzed alkyne amination reactions.
Metal-organic frameworks (MOFs) attract broad interests in mercury (Hg) ion adsorption field, while unreasonable distribution of active groups commonly restricts their utilization efficiency. In this work, we constructed a new MOF (TYUST-6) with dense thiol-rich traps in the 1D pore wall. This accessible channel and rational distribution of thiols allow the smooth diffusion of Hg ions and thereby result in a high Langmuir adsorption capacity of 1347.6 mg/g, almost reaching the theoretical maximum (1444.3 mg/g). Adsorption equilibrium needs 10 and 30 min at the initial concentrations of 10 and 100 mg/L, respectively. Common co-existing ions and solution pH show almost negligible interferences on the adsorption, and adsorbent regeneration can be well achieved. Combining experimental characterizations and theoretical calculations, the thiol groups in the pore wall are proved to be the dominant interaction sites. Thus, this work reports a novel high-capacity adsorbent for Hg2+, and proposes a feasible guideline for designing effective adsorbents.
The interaction between nanoparticles (NPs) and pollutants affects their bioavailability and toxicity. However, the processes by which NPs and pollutants change in vivo have rarely been explored. Here, using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP–MS), we found that both nanoplastics and ZnO NPs caused more Cd to accumulate in zebrafish larvae, but with distinct pathways. Nanoplastics could adsorb Cd2+ and transfer it into the larvae through the "Trojan horse" effect. The coexposure of nanoplastics and Cd2+ caused Cd to accumulate in the abdomen where the nanoplastics were located without dissociation, showing a lower toxic effect than Cd2+ exposure alone. ZnO NPs weakly adsorbed Cd2+, but they increased the Zn and Cd contents in larvae by enhancing the expression of metal transporters. The coexposure of ZnO and Cd2+ evenly distributed Cd in the larvae, revealing a more severe toxic effect than Cd2+ exposure alone. Our results demonstrated the changing bioavailability and toxicity of Cd induced by different NPs. This also shows the vital role LA-ICP-MS plays in revealing the relationship between toxicity and bioavailability. In addition, the long-term effect of bioavailability on heavy metal toxicity and nanosafety deserves further investigation.
Photodynamic therapy (PDT) presents a promising avenue in cancer treatment. Erlotinib, an FDA-approved anticancer drug targeting epidermal growth factor receptor (EGFR), has shown effectiveness in normalizing tumor vasculature across various tumors, thereby promoting tumor oxygenation and facilitating PDT. In this work, erlotinib was conjugated with a near-infrared (NIR) photosensitizer, benzo[a]phenoselenazinium, yielding three EGFR-targeted PDT agents (NBSe-nC-Er). These newly synthesized photosensitizers demonstrate specificity in binding to EGFR, thereby enhancing their accumulation in cancer cells and tumors, and consequently improving the efficiency of both PDT and chemotherapy. Additionally, the NIR fluorescence emitted by the photosensitizer allows for imaging-guided therapy, offering a non-invasive means of monitoring treatment progress. The distinctive properties of the three-in-one photosensitizer render it an ideal candidate for precise tumor treatment, overcoming the limitations of conventional therapies.
Wearable flexible sensor devices have the characteristics of lightweight and miniaturization. Currently, power supply and detection components limit the portability of wearable flexible sensor devices. Meanwhile, conventional liquid electrolytes are unsuitable for the integration of sensing devices. To address these constraints, wearable biofuel cells and flexible electrochromic displays have been introduced, which can improve integration with other devices, safety, and color-coded display data. Meanwhile, electrode chips prepared through screen printing technology can further improve portability. In this work, a wearable sensor device with screen-printed chips was constructed and used for non-invasive detection of glucose. Agarose gel electrolytes doped with PDA-CNTs were prepared, and the mechanical strength and moisture retention were significantly improved compared with traditional gel electrolytes. Glucose in interstitial fluid was non-invasive extracted to the skin surface using reverse iontophoresis. As a biofuel for wearable biofuel cells, glucose drives self-powered sensor and electrochromic display to produce color change, allowing for visually measurement of glucose levels in body fluids. Accurate detection results can be visualized by reading the RGB value with a cell phone.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62662699(Operation and Technical Support)
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
