Latest ArticlesAn iron-catalyzed coupling reaction of difluoroenol silyl ethers and cyclobutanone oxime esters is described. This protocol provides a convenient access to various previously unknown and potentially useful gem-difluoromethylenated ketonitriles inmoderate to good yields. The transformations of resulting products to other fluorinecontaining products is also documented.
Life on Earth uses a common set of l-amino acids (l-aa) to construct proteins and d-nucleosides (d-Nu) to form nucleic acids, which serve as the carrier of genetic information. Herein, we reveal the intrinsic mechanism of chiral selection of l-aa and d-Nu from the perspective of chemical origin of life. This work employed 15N-labeled l-aa and performed one-pot synthesis of nucleotide amidate of amino acid (N-aa-NMP) using equal amounts of l-15N-aa and d-14N-aa with d-/l-Nu in the aqueous solution of trimetaphosphate, generating l-15N-aa-NMP and d-14N-aa-NMP, respectively. The 31P-NMR data indicated that l-aa was preferentially selected during the formation of N-aa-NMP in the presence of d-Nu. Surprisingly, d-aa was preferred over l-aa in the presence of l-Nu. Further analysis revealed that l-15N-aa-d-NMP vs. d-14N-aa-l-NMP and d-14N-aa-d-NMP vs. l-15N-aa-l-NMP were mirror isomers of each other, respectively. These data suggest that there could be a set of chiral systems opposite to that on Earth, which infers there might be a world of life that is a mirror image of the Earth.
The CpXRh(Ⅲ)-catalyzed asymmetric cascade C-H coupling/intramolecular cyclization of azomethine imines with propargyl carbonates has been developed, affording a variety of chiral tetracyclic indenopyrazolopyrazolone frameworks with good substrate/functional group tolerance and enantioselectivity (up to 97:3 er). Combined experimental studies and DFT calculations revealed the Rh(Ⅲ)-catalyzed stepwise annulation process and clarified the synergy coordination mode of dual directing groups in tuning the selectivity.
Light-driven conversion of CO2 into chemicals/fuels is a desirable approach for achieving carbon neutrality using clean and sustainable energy. However, its scale-up application is restricted due to insufficient efficiency. Herein, we present a photothermal catalytic hydrogenation of CO2 into CH4 over Ru/black TiO2 catalysts, aiming to achieve the synergistic use of light and heat in solar energy during CO2 conversion. Owing to the desirable spectral response ability and photothermal conversion performance of black TiO2, an efficient combination of photocatalysis and thermocatalysis has been established. The CO2 hydrogenation was significantly accelerated because of the increased catalyst surface temperature enabled by the photothermal effect of black TiO2. Simultaneously, through the in situ X-ray photoelectron spectroscopy (XPS) observation, electron-rich Ru nanoparticles was achieved based on the photo-induced excitation, thereby providing more negative hydride to improve nucleophilic attack to the CO2, obtaining the CH4 yield of 93.8%.
This work detailed the preparation of a class of water-soluble PNP ligands that differed by the nature of the substitute on phenyl ring of ligands. These ligands were incorporated into water-soluble rhodium-PNP complex catalysts that were used to regioselective hydroformylation of a series of terminal arylalkenes, providing efficient access to rac-α-aryl propionaldehydes in good to excellent yield (up to 97%) and branched-regioselectivity (up to 40:1 b/l ratio). Furthermore, gram-scale and diverse synthetic transformation demonstrated synthetic application of this methodology for non-steroidal antiinflammatory drugs.
As emerging two-dimensional materials, metal-organic framework (MOF) nanosheet composites possess many unique physical and chemical properties, thus being expected to be widely applied in gas separation and adsorption, energy conversion and storage, heterogeneous catalysis, sensing as well as biomedicine. In this review, we first introduce the methods for integrating MOF nanosheets with other materials to prepare multifunctional composites. Next, the applications of MOF nanosheet composites in versatile fields are summarized and discussed. We hope this review will be instructive for researchers in the aspects of designs, preparations and applications of MOF nanosheet composites.
Carbon dots (CDs), because of their unique properties, are being rapidly developed as important luminescent materials for imaging, sensing, and use in photonic devices. However, most of the reported fundamental properties of the CDs are results of investigations conducted in the solution state, which may be completely different from those conducted in the solid state. In this work, we study the luminescence properties, photostability, and the dynamics of CDs in different matrix environments, from ensemble to the single-particle level. We observed that the properties associated with the emission centers and photostability of CDs were extremely sensitive to the local chemical environment. A better understanding of the dependence of the spectroscopic properties of CDs on the complex local chemical environment is an important step toward finding new ways of controlling the optical properties of CDs and optimizing their use in various applications.
The drug resistance of chemotherapy is a major challenge to overcome for antineoplastic agents and the reverse of drug resistant is essential for cancer therapy. Herein, we developed a drug delivery system which can simultaneously detect/reverse the drug resistance and perform synergetic treatment of cancer. In this work, we integrated cyanine5 (Cy5) modified miRNA (let-7i) (Cy5-miRNA) and platinum onto nano-graphene oxide (NGO) (30-50 nm) platform to achieve simultaneously detection/reversion of drug resistance and synergetic treatment of cisplatin resistant SKOV3 cells (SKOV3DDP cells). The Cy5-miRNA adsorbed on NGO could selectively bind the drug resistance related mRNA follow by suppress the expression of drug resistance mRNA, and the binding simultaneously induced the release of Cy5-miRNA from the NGO, thus the fluorescence signal of Cy5 recovered and could be used for drug resistance monitoring. Moreover, the miRNA suppressed the Cyclin D1 protein expressions thus reversed the drug resistance. The loaded platinum(IV) (Pt(IV)) was converted to the therapeutic platinum(II) (Pt(II)) in both tumor acidic and reductive environment responsive behavior. NGO furtherly performed photothermal therapy under near infrared (NIR) laser irradiation and enhanced the therapeutic effect. All in all, this nanoplatform realized detection/reversion of the drug resistance as well as synergetic chemical-photothermal treatment of ovarian cancer cells, which holds great promise in the treatment of drug resistant cancer cells.
The undesirable enzymatic activity of nanozymes under near neutral pH condition and the traditional single signal output always restrict the analytical application of nanozyme-based biosensors. Herein, graphitic carbon nitride nanosheets supported palladium nanosheets composite (Pd/g-C3N4) with both oxidase-like activity and fluorescent property is synthesized. Notably, Pd/g-C3N4 exhibits enhanced oxidase-like activity compared to Pd NSs under pH 7.4. By combining Pd/g-C3N4 with o-phenylenediamine (OPD), a ratiometric fluorescence assay for acetylcholinesterase (AChE) activity detection is developed. Pd/g-C3N4 can catalyze oxidation of nonfluorescent OPD to fluorescent oxidized OPD (oxOPD, Em = 565 nm), which can quench fluorescence of g-C3N4 supporter (Em = 441 nm) through fluorescence resonance energy transfer (FRET). However, in presence of AChE, acetylthiocholine can be hydrolyzed into thiocholine, which will block the oxidase-like activity of Pd/g-C3N4 and then hamper the FRET process. This ratiometric fluorescence assay is also viable to screen AChE inhibitor. This work will guide design of ratiometric fluorescence assay based on nanozymes with improved enzymatic activity.
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
