Chinese Journal of Chemistry最新文献

Here, we show a cost-effective and environmentally friendly method for synthesizing iminofuranones using visible light and the photocatalyst 2-bromoanthraquinone. Our approach uses only oxygen as the oxidant, avoiding the need for additional transition metals and strong oxidizing agents. By employing a mixed solvent system of DMF and CHCl₃ under ambient conditions, we have achieved highly diastereoselective conversions of various 2-vinyl benzamides and alkenyl amides into functionalized iminoisobenzofuranones and iminofuranones. This versatile process is broadly applicable and enables late-stage structural modifications of complex substrates with bioactive moieties.

Inspired by the molecular mechanism of mussel adhesion, here, we developed a class of injectable and self-healing hydrogels based on natural polysaccharide hyaluronic acid (HA). The dynamic property of hydrogels is derived from histidine-metal coordination, which widely exists in the mussel adhesive plaque. To mimic components of mussel byssal threads, we first grafted histidine-containing peptides onto the HA chains. Followed by the addition of Zn²⁺ ions, the modified HA could then transform into a pH-sensitive hydrogel network (HA-His-Zn) with tunable sol-gel transitions. The dynamic metal-ligand coordination could significantly enhance the mechanical properties of HA hydrogels and also endow them with self-healing and injectable abilities. In addition, the HA-His-Zn hydrogels could also exhibit antibacterial and immunoregulatory activities due to the bioactive Zn²⁺ ions. These results, together with the dynamic properties and good biocompatibility, indicated that the HA-His-Zn hydrogels could be applied as a class of easy-to-handle scaffold materials for regeneration medicine, particularly for tissue traumas with chronic inflammations and infections.

The synthesis of titanium oxo clusters (TOCs) with both chirality and photoactivity is urgently needed to expand their applications. However, this remains a significant challenge due to synthetic difficulties and limitations in chiral ligand selection. In this work, we have isolated two pairs of enantiomeric TOCs, [Ti₃(μ₃-O)(R/S-L1)₂(ⁱPrO)₆] (R/S-Ti3; ⁱPrOH = isopropanol, R/S-L1 = R/S-2'-hydroxy-[1,1'- binaphthalen]-2-yl isopropyl hydrogenphosphate) and [Ti₄(μ₂-O)(μ₄-O)(R/S-L2)₂(EtO)₈] (R/S-Ti4; EtOH = ethanol, R/S-L2 = R/S-2'-hydroxy-[1,1'-binaphthalen]-2-yl ethyl hydrogenphosphate), via an in situ ligand transformation approach. The R/S-L1 and R/S-L2 ligands were obtained by alcoholysis of R/S-L (R/S-1,1'-binaphthyl-2,2'-diyl hydrogenphosphate) in different reaction solvents. These ligands, with additional coordination sites, facilitated the formation of novel TOCs and improved their stability. Importantly, these clusters exhibited exceptional stability in solid state and maintained appreciable stability in solution. Furthermore, the introduction of chiral ligands not only imparts a homochiral nature to R/S-Ti3 and R/S-Ti4 but also confers upon them superior photoelectric properties due to ligand-to-metal charge transfer (LMCT) phenomena, as confirmed by theoretical calculations. This study offers a valuable synthetic strategy for preparing photoactive chiral TOCs, and we anticipate it will inspire new discoveries in the field of chiral metal nanoclusters.

The construction of luminescent two-dimensional (2D) imine-linked covalent organic frameworks (COFs) is a formidable challenge due to the strong interlayer stacking and bond rotations that typically suppress intramolecular charge transfer (ICT), leading to nonradiative energy dissipation. Herein, three COFs with tailored interlayer distances and bond rotations are designed to modulate the ICT behaviours. The targeted COF (TPAZ-TPE-COF) achieved a significantly enhanced photoluminescence quantum yield (PLQY) of 21.22% in the solid state by restricting bond rotation and enlarging the layer distance. This represents a 3.5-fold and 530.5-fold improvement over TPAZ-PYTA-COF (6.15%), which has a shortened interlayer space, and TPAZ-PATA-COF (0.04%), which exhibits strong bond rotations, respectively. Importantly, TPAZ-TPE-COF also exhibits exceptional sensing performance for iron ions, with a detection limit at the ppb level. Both experimental and theoretical analyses reveal that the prominent luminescent performance of TPAZ-TPE-COF is assigned to the effective suppression of nonradiative pathways, especially those arising from interlayer stacking and bond vibrations. These findings pave the way for deliberate construction of imine-linked 2D COFs with high PL intensity, thereby expanding the portfolio of luminescent COFs with potential applications in sensing and optoelectronics.

The eradication of Pseudomonas aeruginosa infections is becoming increasingly complex due to the emergence of multidrug-resistant strains, underscoring the urgent need for novel therapeutic strategies. Currently, no vaccine is available to prevent P. aeruginosa infections and the development of glycoconjugate vaccines based on P. aeruginosa lipopolysaccharides (LPS) presents significant challenges. To explore the immunological activity of the serotype O17 O-antigen, we present the first chemical synthesis of two hexasaccharides derived from the O17 O-antigen of P. aeruginosa, which possess distinct sequences. The synthesis of these two target hexasaccharides was accomplished using a chemoselective one-pot [2+2+2] assembly strategy and a common step-wise synthesis, respectively. The formation of β-mannosamine glycosidic linkages in products 1 and 2, was achieved through a direct stereoselective 1,2-cis-glycosylation involving 4,6-O-benzylidene-induced conformational locking facilitated by Ph₂SO/Tf₂O pre-activation, and an indirect 1,2-trans-β-glycosylation alongside S_N2 substitution of azide groups at C2, respectively. The efficient synthesis of these conjugation-ready oligosaccharides from the O-antigen of P. aeruginosa serotype O17 will provide foundational materials for identifying key antigens and developing glycoconjugate vaccines.

The frequent occurrence of oil spills not only results in the waste of petroleum resources, but also poses a serious threat to the marine ecological environment. Considering the large amount of crude oils with high viscosity, it is urgent to develop a sorbent capable of efficiently reducing the viscosity for the cleanup of oil spills. Inspired by the “lotus effect” and “poikilotherm which utilize the solar energy for thermoregulation”, the low surface energy material polydimethylsiloxane (PDMS) and polypyrrole (PPy) were loaded over the island nonwoven fabric to fabricate a novel crude oil sorbent material. The nonwoven fabric achieved an efficient photothermal conversion. Wherein, the fluorine-free PDMS was used to hydrophobically modify the nonwoven fabric, endowing it with excellent oil-water separation performance, with a separation efficiency of up to 95%. After 10 cycles, the separation efficiency of PPy/PDMS modified nonwoven fabric (PPy/PDMS@NF) was still above 90%, demonstrating superior recyclability. In addition, the PPy/PDMS@NF possessed the self-cleaning capabilities. Under light conditions, the PPy/PDMS@NF was rapidly heated up, reducing the viscosity of crude oil and enabling the effective recovery of oil spills. Under one sun illumination (1.0 kW·m^–2), the surface temperature of the PPy/PDMS@NF reached 60.7 °C, and its sorption capacity for high-viscosity crude oil reached 7 g_{crude oil}·g_sorbent^–1. Thanks to its environmental friendliness and excellent sorption capacity, this work provides a new option for dealing with the high-viscosity marine oil spills.