Science China Chemistry最新文献

The field of polymer mechanochemistry has been revolutionized by implementing force-responsive functional groups—mechanophores. The rational design of mechanophores enables the controlled use of force to achieve constructive molecular reactivity and material responses. While a variety of mechanophores have been developed, this Mini Review focuses on cyclobutane, which has brought valuable insights into molecular reactivity and dynamics as well as innovations in materials. We discuss its reactivity and mechanism, dynamics and stereoselectivity, as well as impacts on material properties.

In order to mitigate the environmental impact of polyethylene terephthalate (PET) plastic pollution and enhance waste resource utilization, we developed a novel Ir-ReO_x/SiO₂ + HZSM-5 catalytic system for the hydrodeoxygenation (HDO) of PET plastic wastes into cycloalkanes, particularly 1,4-dimethylcyclohexane (DMCH). Under mild conditions (190 °C, 3 MPa H₂) with a certain amount of water in cyclopentane solvent, the highest yield of DMCH reached 95.8%, contributing to an overall yield of cycloalkanes at 98.4% within a reaction time of 4 h from HDO of virgin PET. The HDO of PET into DMCH involved initial hydrogenation of PET aromatic ring, then depolymerized by direct hydrogenolysis of acyl C–O bond in the ester group and subsequent cascade HDO of alcoholic C–O bond to saturated ester and alcohol intermediates, and further HDO of these oxygenates converting into desired DMCH product. The Ir-ReO_x/SiO₂ catalyst exhibits fully reduced metallic Ir nanoparticles along with partially reduced ReO_x species that are highly dispersed on both SiO₂ surface and Ir nanoparticle surfaces. The oxophilic nature of ReO_x species facilitates the activation of C–O bonds, the acidic HZSM-5 zeolite for the promotion of dehydration reaction, and the protic property of H₂O for the enhancement of hydrogenation PET contributed to highly HDO activity of this system. Furthermore, the catalytic system is applicable for the HDO of diverse real-world PET plastic wastes including Coca-Cola™ bottles, green Sprite bottles and white and red discarded fiber cloths, generating DMCH with a yield of up to 95.9% and cycloalkanes with a yield of up to 99.5%. This innovative process presents a new avenue for efficient hydrodeoxygenation conversion of PET into easily separable DMCH which serves as a crucial building block for the production of terephthalic acid to realize the chemical recycling of PET plastic wastes towards a green circular economy.

Two-dimensional (2D) materials are vital for the development of advanced materials in the next-generation energy conversion and storage devices. In-situ liquid-phase transmission electron microscopy (LP-TEM) acts as a powerful tool for characterizing the dynamic evolution of materials under work condition in real time and in operando. Herein, this mini-review highlights the considerable advances in the utilization of in-situ LP-TEM for studying the physical and chemical process dynamics of 2D materials, such as their nucleation growth and phase transformation. The electrocatalytic water splitting reactions and CO₂ electroreduction of 2D energy materials are highlighted. The underlying electrochemical reaction mechanisms of the 2D electrode materials in rechargeable batteries are discussed and summarized. Finally, the current challenges and perspectives for future research are proposed. This min-review aims to inspire and stimulate further innovation and encourage the broader adoption of LP-TEM in exploring the fascinating dynamics of 2D energy materials.

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.

Alzheimer’s disease (AD) is a neurodegenerative disease and a major threat to human health worldwide. The association between aluminum exposure and AD has been widely reported. Owing to the ubiquitous presence of aluminum in daily life, aluminum exposure can easily occur whenever and wherever possible. Thus, a rapid and sensitive reagent for detecting aluminum and assist in AD daily prevention for potential AD patient population is extremely needed. However, existing aluminum detection methods rely on precise instruments, which are impractical for household use. Herein, a series of aggregation-induced emission-based covalent-organic framework (AIE-COF) fluorescent probes has been designed with progressively tuned sizes and screened for aluminum detection. Among them, COF-N2 was found to have the highest response towards aluminum specifically, with a fluorescence intensity change of 19.14 times before and after chelation, which could determine the aluminum concentration by naked eye. Then, the molecular mechanism of COF-N2 fluorescence changes was explained and COF-N2 was used for both diagnose the aluminum distribution in various organs of APP/PS1 transgenic mice and quickly determine the aluminum content in daily necessities. The use of AIE-COF probes for aluminum detection provides a promising avenue for developing aluminum related AD clinical diagnosis and daily prevention tools.

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.

Electron transport layers (ETLs) play a pivotal role in determining the efficiency and stability of inverted structure organic solar cells (OSCs). Zinc oxide nanoparticles (ZnO NPs) are commonly used as ETLs due to their mild deposition conditions and compatibility with flexible plastic substrates, facilitating scalable manufacturing. In this study, we introduce a molecule called NMO, which serves a dual purpose: efficiently dispersing ZnO nanoparticles and acting as a surface modification layer for ZnO NPs thin films. The hybrid ETL created by blending and surface modification with NMO significantly enhances both the efficiency and stability of OSCs. Inverted structure OSCs, based on the PM6:Y6 system and utilizing the hybrid ETL, achieve impressive power conversion efficiency (PCE) of 18.31%. Moreover, these devices demonstrate exceptional stability during shelf storage (T₈₀ = 19,650 h), thermal aging (T₈₀ = 7783 h), and maximum power point tracking (T₈₀ = 3009 h). Importantly, the hybrid ETL exhibits good generality, as all tested OSCs utilizing it display significantly improved efficiencies and stabilities. Notably, a PCE of 19.23% is attained for the PM6:BTP-eC9-based device, marking the highest reported efficiency for inverted single-junction OSCs to date.

We report a tandem asymmetric Cu-catalyzed propargylic animation (ACPA)/Ag-catalyzed carboxylative cyclization (SCC) with CO₂ to 5-methylidene-2-oxazolidinones, even with tetrasubstituted stereocenters. By varying pyridine bisoxazoline (PYBOX) ligands, a general and highly enantioselective ACPA of unprecedentedly broad scope of secondary propargylic acetates and primary amines is achieved. Both α-aryl and α-aliphatic propargylic acetates could react with either aromatic or aliphatic primary amines to give the corresponding N-aryl or N-aliphatic ethynylamines with α-aliphatic or α-aryl groups in over 90% ee for use in the next step. The key to developing this one-pot sequence is to use a chelator triethylenetetramine (TETA) to mask the copper ion, to avoid its negative effect on Ag-catalyzed cyclization, whilst releasing PYBOX to activate the silver catalyst. With the methylidene moiety, these oxazolidinones can be readily elaborated. The value of the sequence is further shown by the catalytic enantioselective total synthesis of (−)-cytoxazone and the potent ezetimibe analogue.