Chinese Journal of Chemistry最新文献

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.

The power conversion efficiencies (PCEs) of non-fullerene acceptor (NFA)-based organic solar cells (OSCs) have undergone an exciting development in recent years, but the poor intrinsic stability of exocyclic ethylene bridges in NFAs poses a significant challenge to their commercialization. In this work, we propose a new pyran-locking strategy that can stabilize the exocyclic ethylene bridge connecting the strong electron-deficient 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile end group, based on which two dimerized NFAs (ITBIC-F and TBTBIC-F) with an A-D-π-A-π-D-A structure have been successfully synthesized with significantly improved chemical and photochemical stabilities in comparison with traditional NFAs without the ring-locked structure. The ITBIC-F and TBTBIC-F -based OSCs not only achieve promising PCEs of 13.03% and 10.01%, respectively, but also show good device stability; the ITBIC-F-based unencapsulated devices can retain 75% and 62% of their initial PCEs, respectively, under continuous heat (85 °C) and light irradiation (LED, 100 mW·cm^–2) in a nitrogen atmosphere.

The invention of novel linkers is a long-lasting task in the area of the sulfur(VI) fluoride exchange reaction (SuFEx). Compared with the most frequently investigated sulfonyl fluorides, synthetic accessibility toward its mono-aza isostere, i.e., sulfonimidoyl fluorides is still limited. Herein, we report an electrochemical carbonfluorination of the readily available N-sulfinylamines to access various aryl and alkyl sulfonimidoyl fluorides. The transformation is characterized by the ready availability of starting materials, mild reaction conditions, and obviating metal catalysts and chemical oxidants.

We synthesized a dialane(4) compound (2) stabilized by double-layer N-P ligands. Upon reduction with KC₈, compound 2 demonstrates solvent-dependent reactivity: in THF, it undergoes C—O bond cleavage to yield product [MeN(CH₂CH₂NPiPr₂)₂Al(CH₂)₄O]₂K₂; whereas in a THF/toluene mixture, it results in the activation of the methyl C—H bond in toluene, forming product [MeN(CH₂CH₂NPiPr₂)₂AlH]₂K₂. We propose that these reactions involve an “Al(I)” intermediate, which facilitates oxidative addition with either the C—O bond of THF or the C—H bond of toluene.

Herein, a [1,2]-phospha-Brook rearrangement-initiated palladium-catalyzed cyclization reaction for base-controlled selective synthesis of 2H-isoindole-1-carboxamide and 2H-isoindole-1-carbonitrile derivatives has been described. This strategy features double isocyanide insertion, efficient bond combinations, simple operation and reaction conditions. Mechanistic studies show that the [1,2]-phospha-Brook rearrangement is the key step in this reaction. This protocol offers a novel and concise strategy for the synthesis of 2H-isoindole derivatives.

Due to the extremely similar physical and chemical properties of C₂H₆, C₂H₄, and C₂H₂, purifying ethylene from the C₂ ternary mixture in one-step is very challenging. In this work, we developed a series of pillar-layered MOF materials ((Ni(BTC)(Bipy), Ni(BTC)(3-Me-Bipy), and Ni(BTC)(3-NH₂-Bipy)) through the functionalization of pillar ligands using pore engineering strategies. Single-component adsorption isotherm measurements demonstrate that these materials preferentially adsorb C₂H₆ and C₂H₂, thereby achieving one-step purification of the three C₂ hydrocarbons to obtain C₂H₄. By introducing functional groups on the pillars, the selectivity for C₂H₆/C₂H₄ increased by over 10%, while the selectivity for C₂H₂/C₂H₄ increased by more than 300%. Specifically, Ni(BTC)(3-NH₂-Bipy) exhibits a selectivity of 1.5 for C₂H₆/C₂H₄ (50/50, V/V) and 5.16 for C₂H₂/C₂H₄ (1/99, V/V). Under ambient conditions, the adsorption capacity of Ni(BTC)(3-NH₂-Bipy) for C₂H₂ reached 121.6 cm³/g, Ni(BTC)(3-NH₂-Bipy) exhibits superior C₂H₂ adsorption capacity and C₂H₂/C₂H₄ selectivity compared to many classic materials, including TJT-100, Azole-Th-1, and MOF-808-Bzz, commonly used for C₂H₄ purification from C₂ ternary mixtures. Dynamic breakthrough experiments indicate that in a ternary C₂ mixture, Ni(BTC)(3-NH₂-Bipy) preferentially captures C₂H₆ and C₂H₂, enabling one-step purification of C₂H₄.

Terpyridine ligands have been applied as a class of unique ligands due to their rich coordination chemistry in the catalysis. Herein, we developed a new class of C₂-symmetric chiral terpyridine-pyrroloimidazolone ligands (TPy-BPI). Their catalytic activity was evaluated in the asymmetric Friedel-Crafts alkylation of indoles with 2,3-dioxopyrrolidines. Excellent yields (up to 92%) and high enantioselectivities (up to 97% ee) are obtained for a wide range of substrates under mild conditions. In addition to 2,3-dioxopyrrolidines, β,γ-unsaturated α-ketoesters were also compatible in the Ni(OTf)₂-TPy-BPI ligand L1-catalyzed reaction. Control experiments, single crystal structure of two TPy-BPI L1-Ni(OTf)₂ complexes, and DFT calculations revealed the origins of the enantioselectivity. To the best of our knowledge, our work is the first report showing that the terpyridine framework contained only two nitrogen atoms coordinating with the metal, and the additional pyridine unit only acted as stereodirecting element, which is different from the previously reported terpyridine ligands containing all three nitrogen atoms coordinating with the metal.