Latest ArticlesThe tuning of olefin-polymerization catalyst properties through ligand modifications is efficient but requires complicated and costly syntheses. In this contribution, a simple Bu2Mg-based cocatalyst strategy is designed that can simultaneously enhance the catalytic properties (activity, thermal stability, polymer molecular weight, branching density, melting point, etc.) of various nickel catalysts (α-diimine nickel, pyridine imine nickel and iminopyridine-N-oxide nickel) in ethylene polymerization, and enable great product morphology control. For example, a simple α-diimine nickel catalyst can demonstrate polymerization activity of up to 1.29 × 107 g mol−1 h−1 and molecular weight of up to 1.90 × 106 g/mol in the presence of Bu2Mg cocatalyst. The resulting polyethylenes exhibit excellent mechanical properties, with tensile stress of up to 47.4 MPa and strain of up to 1020%. This cocatalyst strategy is generally applicable to different nickel catalysts, and can lead to property enhancement in ethylene copolymerization with a series of polar comonomers such as methyl 10-undecylenate, 10-undecylenic acid and 10-undecenol.
Nanoscale metal organic frameworks (NMOFs) have been widely reported in biomedical field for their unique porous structure and tunable multifunctionality. However, when administrated in vivo, the protein corona will be formed on the surface of NMOFs, significantly affecting their biodistribution, pharmacokinetics and drug release. Few studies paid attention to the protein corona formation process and its influencing factors of NMOFs. As a well-established strategy for altering structure features of NMOFs, the organic ligand modification may have effect on the protein corona formation process, which is to be investigated. In this study, the zirconium (Zr)-based UIO66 was chosen as model NMOFs, the organic ligand of which was modified with amino group (-NH2) or carboxyl group (-COOH) to synthesize UIO66-NH2 and UIO66-2COOH, respectively. Bovine serum albumin (BSA) was chosen as model protein to investigate the protein corona formation process of NMOFs. The current results showed that the -COOH modification remarkably enhanced the BSA adsorption on NMOFs while -NH2 slightly decreased the protein binding affinity. These differences may be ascribed to the two different dominate protein corona formation modes, i.e., surface coating mode and porous embedded mode. The protein corona formation did not affect the crystal phase of NMOFs but increased the content of α-helix of BSA. Ultimately, upon protein corona formation, the cellular uptake of NMOFs was significantly affected. We believe our study will provide a new research paradigm to the design and applications of NMOFs.
Solid-state electrolytes (SSEs) with high ionic conductivity, mechanical stability, and high thermal stability, as well as the stringent requirement of application in high-temperature fuel cells and lithium-ion batteries is receiving increasing attention. Polymer nanocomposites (PNCs), combining the advantages of inorganic materials with those of polymeric materials, offer numerous opportunities for SSEs design. In this work, we report a facile and general one-pot approach based on polymerization-induced microphase separation (PIMS) to generate PNCs with bi-continuous microphases. This synthetic strategy transforms a homogeneous liquid precursor consisting of polyoxometalates (POMs, H3PW12O40, Li7[V15O36(CO3)]), poly(ethylene glycol) (PEG) macro-chain-transfer agent, styrene and divinylbenzene monomers, into a robust and transparent monolith. The resulting POMs are uniformly dispersed in the PEG block (PEG/POM) to form a conducting pathway that successfully realizes the effective transfer of protons and lithium ions, while the highly cross-linked polystyrene domains (P(S-co-DVB)) as mechanical support provide outstanding mechanical properties and thermal stability. As the POM loading ratio up to 35 wt%, the proton conductivity of nanocomposite reaches as high as 5.99 × 10-4 S/cm at 100 ℃ in anhydrous environment, which effectively promotes proton transfer under extreme environments. This study broadens the application of fuel cells and lithium-ion batteries in extreme environments.
Fluorescent dyes play a crucial role in fluorescence imaging and sensing technology. However, there is a dilemma that they are usually intrinsically hydrophobic which lacks of emission in water and modification with ionic groups to access water solubility may result in poor membrane permeability. Fluorescent dyes with strong fluorescence emission in both nonpolar and polar solvents are highly desirable. In this manuscript, we reported a strategy to develop fluorescent BODIPY dyes via installation of amide moiety at meso position of 1, 3, 5, 7-tetramethyl-BODIPY and discovered that N, N'-dialkylsubstituted BODIPY amides possessed highly fluorescent emission with favorable environment-insensitive properties.
While N-alkenoxypyridinium salts are widely used for the synthesis of α-functionalized ketones via umpolung strategy, such approaches are usually limited to special nucleophiles at high temperatures. Herein, we developed an alternative photoinduced N-heterocyclic carbene (NHC)- mediated functionalization of N-alkenoxypyridinium salts with various nucleophiles, including tetramethylammonium azide, secondary amines, aryl and alkyl thiols, and even the challenging C(sp3)-nucleophiles, under mild conditions. A cascade radical-radical coupling/nucleophilic substitution sequence was proposed, wherein the NHC enabled the formation of a photoactive electron donor-acceptor complex for α-iodo ketone synthesis.
Herein, we reported a convenient and efficient multicomponent reaction of indoles, selenium powder and unactivated alkyl halides. This protocol provides a practical, and facile approach for the synthesis of 3-alkylselenindole derivatives. The advantages of this strategy include mild and transition-metal-free conditions, broad functional group tolerance, the use of simple and easily accessible seleniium powder and alkyl halides as coupling partners. More importantly, the reaction proceeded smoothly with a large scale (> 10 g, > 90% yield), which further highlighted the potential application of this selenation strategy.
Phosphorylated di-, tri- and tetra-saccharides of β-1, 2-mannan antigen derived from Candida albicans (C. albicans) cell wall were synthesized and covalently conjugated with keyhole limpet hemocyanin (KLH) and human serum albumin (HSA) via a bifunctional linker under mild conditions. The semi-synthetic β-1, 2-mannoside–KLH conjugates were evaluated for the immunization of BALB/c mice. The ELISA results revealed that all three conjugates could elicit high levels of specific IgG antibodies and the acquired antisera could effectively identify the β-1, 2-mannan epitope. Furthermore, the immunofluorescence and flow cytometry assays also uncovered that the induced antibodies, especially that obtained from immunization with β-1, 2-mannotriose–KLH conjugate (1b), could bind well to fungi cell. Eventually, the structure–immunogenicity relationship analysis of β-mannan showed that the length of oligo-β-mannoses had a big impact on their immunogenicity and β-1, 2-mannotriose showed the strongest immunogenicity. The results suggested the great potential of β-1, 2-mannotriose–KLH conjugate as an antifungal vaccine candidate.
Riboflavin (RF, vitamin B2) is an essential vitamin and has been considered as a promising natural photosensitizer for photodynamic therapy (PDT). However, further exploration of RF in antitumor application was limited by its poor cellular uptake. In this study, using cell-penetrating peptides Arg8, (Cha-Arg)3 and small molecule triphenylphosphine (TPP) as delivery compounds, three RF conjugates were prepared to increase the accumulation of RF in cells, termed as Arg8-RF, (Cha-Arg)3-RF and TPP-RF, respectively. Compared with TPP-RF and Arg8-RF, (Cha-Arg)3-RF exhibited better cell internalization and stronger cytotoxicity against HeLa cells upon exposure to blue light. Further researches proved that (Cha-Arg)3-RF generated reactive oxygen species (ROS) under irradiation, which could indiscriminately destroy endogenous proteins and mitochondria, ultimately inducing cell death. This work provides a new approach to explore RF as a natural photosensitizer for antitumor photodynamic therapy.
Although the construction of specific functional crystalline materials is still challenging, the multi-component molecular assembly has become a key solution for the design of functional materials. Here, we report a hydrogen-bonded organic framework (HOF) material FJU-360 constructed from disodium 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate (SSY) and terephthalimidamide. The charge-assisted hydrogen bonding between amidinium and sulfonate makes FJU-360 produce much stronger fluorescence than SSY, and can be used as a luminescence sensor to rapidly quench aniline through luminescence quenching. FJU-360 is sensitive and highly selective for the detection of aniline, and the detection limit reached 3.2 nmol/L, which is the lowest value reported currently. The mechanism of aniline response was analyzed through the aniline@FJU-360 single crystal structure, and the luminescence mechanism was clarified through density function theory calculations. This work is an important step towards the rational synthesis and assembly of sensing materials.
Luminescent metal organic cages (MOCs) have attracted great interest as a unique class of sensing substrates. In this work, intrinsically fluorescent Zr-MOCs were successfully used as fluorescent probes for the sensitive and selective detection of phosphate anions in water and real samples. When the ligand and Zr ion clusters form a cage, the intrinsic fluorescence of the ligand was tuned from high to weak emission due to the ligand-to-metal charge transfer (LMCT) effect, and this weakened fluorescence can be restored by the addition of phosphate. The degree of fluorescence enhancement is positively correlated with the added phosphate concentration, and the efficacy of this strategy is demonstrated by a linear phosphate detection range of 5–500 µmol/L and a detection limit of 1.06 µmol/L. We discuss the interaction between phosphate and Zr in scattering spectrum and MS, respectively. In comparison to phosphate adsorption on Zr-metal organic frameworks (MOFs), where phosphate connects different numbers of cages, both blocking the LMCT effect and causing the cages to aggregate. We also found that the phosphate displaces the ligand from the cage when the phosphate concentration is further expanded, resulting in the formation of new derivatives. This derivative was shown to be useful as a Lewis acid catalyst and as a rare earth ion adsorbent.
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
