Science China Chemistry最新文献

The integration of nanostructures with compositional optimization is crucial for enhancing their catalytic performance. Herein, a yolk-shell structured catalyst incorporating a Bi₂O₃/Bi₂O₂CO₃ heterojunction is developed for CO₂ electroreduction. This design combines precise nano-structuring with optimized compositional control, expanding the specific surface area, exposing more highly active catalytic sites, accelerating charge transport and improving mass transfer. As a result, the catalyst exhibits superior catalytic performance with 92.3% formate selectivity and a partial current density of −43.3 mA cm⁻² at −1.0 V vs. RHE. The precisely engineered nanostructures and heterojunction composition exhibit a good stability during the catalysis with negligible degradation in the catalytic process.

Plasmonic nanostructures have been widely employed to enhance the chiral light-matter interactions for chirality sensing owing to their intriguing optical properties. However, a quantitative understanding of the correlation between enhanced molecular chirality and plasmonic properties in plasmonic nanoparticle-molecule complexes remains a challenge yet to be addressed. Here we demonstrate the complex interactions between Ag nanoparticles and biomolecules that generate distinct plasmonic circular dichroism signals ranging from UV to visible wavelengths. By deliberately changing the surface coverage of chiral molecules, the geometry of Ag nanoparticles, and the aggregation states of the complexes, three distinct underlying mechanisms were found to be intertwined and hybridized for enhancing circular dichroism signals. We further employed the chiral plasmonic nano-particle-molecule complexes to quantify the enantiomeric purity of cysteine and explore their possible applications in other chiral molecules. The insights gained from this work shed light on the underlying mechanisms dictating the enhanced circular dichroism signals of chiral plasmonic nanoparticle-molecule complexes.

Mesoporous metals with large surface area, high pore volume, and uniform pore structure hold excellent advantages for various applications. However, the state-of-the-art synthesis methods are still limited to wet chemistry, which requires excessive solvents and a time-consuming drying process. Here, we report a facile and general mechanochemical coordination self-assembly strategy to prepare mesoporous metals (e.g., Rh, Ru, Ir, Pt, Pd, Ag, Co, and Ni) with remarkable porous properties by using metal chlorides and cationic polymer interplay. Compared with the wet chemistry process, this method proceeds without solvents and does not need complicated experimental conditions and long synthetic periods, which not only greatly reduces the consumption of cost and energy and environmental pollution, but also improves the synthesis efficiency and yield of target products. We believe the developed approach will provide a general pathway for the scalable preparation of advanced porous materials.

Developing organic multiple-resonance (MR) deep-blue emitters with narrow full widths at half maximum (FWHMs) is crucial for enhancing the color purity of organic light-emitting diodes (OLEDs). However, the exploration of new MR cores remains very limited to date. Furthermore, redshifting the emission color of MR emitters is also a formidable challenge. Pyrazine, characterized by its planar and rigid structure, exhibits a strong electronegativity, which may make it a promising candidate for constructing MR emitters with a red shifted emission compared to indolo[3,2,1-jk]carbazole (ICz)-based MR molecules. Herein, a series of polycyclic aromatic hydrocarbons (PAHs) with MR characteristics are designed and synthesized by integrating a pyrazine core with various electron-donating segments, which exhibit the narrowband deep-blue emission peaks ranging from 423 to 459 nm with FWHMs < 50 nm in toluene. It is demonstrated that increasing donor strength and changing meta- to para-oriented nitrogen atom can induce the bathochromic emission. Theoretical investigations reveal that the non-bonding orbital characteristic of pyrazine suppress the undesired stretching vibration and promote resonance effect. The optimized deep-blue OLEDs fabricated with the pyrazine-embedded MR emitters demonstrate a high external quantum efficiency (EQE) of 23.5%, and narrowband emission with an electroluminescence peak at 454 nm.

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase SpeF and P450 monooxygenase SpeG, is identified in the biosynthesis of spiro polycyclic alkaloids (+)-notoamide B and its diastereomer (+)-versicolamide B. Using notoamide E as a substance, SpeF/SpeG metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-mA with dienyl iminium unit. Subsequently, (+)-notoamide B and (+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

N-heterocyclic carbene (NHC) organocatalytic reactions that have been developed for asymmetric construction of axial and planar chirality are systematically summarized and discussed in this review. The challenges and limitations inherent to this highly reactive research field are highlighted towards the end of the review. Additionally, based on our understanding of the current advancements in NHC organocatalysis, we propose potential future directions for further exploration.

Circularly polarized luminescence (CPL) has attracted growing attention for their promising applications in chiral functional devices. Achieving CPL materials with both high luminescence dissymmetry factors (g_lum) and emission efficiency is attractive but remains great challenges. In this study, a pair of chiral Cu(I) complexes named R/S-CuI with C₂ symmetry were synthesized, exhibiting no emission in solution and weak CPL with g_lum = ± 3.3×10⁻³ in crystalline state. Transparent chiral films (R/S-CuI-film) were developed through the co-assembly of R/S-CuI and achiral polymer PMMA. The films show bright green luminescence with the quantum yields about 200 times higher than those in crystalline state. Meanwhile, the maximum |g_lum| value is also amplified by approximately 2.5 times, reaching to 8.7×10⁻³. Mechanism investigation suggests that the notable enhancement of luminescence efficiency can be ascribed to the restriction of the intramolecular motions and the elimination of the oxygen quenching effect, while the improvement in g_lum values may be explained by the chirality transfer from the axially chiral molecule R/S-CuI to the achiral polymer PMMA. Furthermore, R/S-CuI-film were used for advanced information encryption applications based on its CPL characteristics. This work may provide new inspirations for the construction of CPL-active films with high performance, thereby expediting their further development.

In this work, we report a visible light-induced energy transfer process related photochemical protocol of cumulative diene containing compounds for the construction of benzocyclohexene skeletons or the corresponding aromatized structures through an energy transfer process, 1,5-hydrogen atom transfer and a 6π electrocyclization or demethoxylation in the presence of different photocatalysts such as [Ir(dF(Me)ppy)₂(dtbbpy)]PF₆ or thioxanthone. This newly developed photochemical strategy is characterized by mild conditions, broad substrate applicability, good functional group tolerance and good yields. The mechanistic paradigm was clarified by deuterium labeling, kinetic, photophysical and electrochemical analyses, control experiments and density functional theory (DFT) calculations. The transformation of the obtained product to the drug-like molecules such as Sertraline and the luminescent conjugated aromatic compounds has also been disclosed.