Science China Chemistry最新文献

In nature, enzymes at specific folded conformations exhibit high substrate complementarity, enabling them to efficiently and selectively catalyze biochemical reactions. Inspired by enzymes, coordination cages with conformational dynamics have been designed and are receiving increasing attention due to their versatile applications in allosteric guest binding and catalysis. We present here two enzyme-mimicking adaptive macrocycle-based coordination cages, Pd₂L¹₂ and Pd₂L²₂, from macrocycle-based ligands (L¹ and L²) and the encapsulation and stabilization of Lindqvist polyoxometalates anions M₆O₁₉²⁻ (M = W or Mo) in neutral aqueous solution. X-ray crystallographic studies have verified the formation of 1:1 host-guest complexes of two Pd₂L₂ cages and the W₆O₁₉²⁻. anion, via an induced-fit folding mechanism. Compared with the free host, Pd₂L¹₂ exhibited an induced-fit semi-folded conformation in the inclusion complex, while Pd₂L²₂ adopted an induced-fit fully-folded conformation. Moreover, the Mo₆O₁₉⊂Pd₂L₂ host-guest complexes demonstrate high yield and selectivity in the oxidative decontamination reaction of the sulfur mustard simulant, 2-chloroethyl ethyl sulfide. This work not only sheds light on the importance of conformational adaptability in enzyme-like systems but also paves the way for protecting labile POM clusters via host-guest encapsulation toward enhanced catalytic performance in aqueous solution.

The high-value utilization of industrial solid waste using a facile and eco-friendly process is of great interest and significance in reducing environmental pollution and developing a green circular economy. Herein, we propose an amyloid-mediated molecular engineering strategy to transform particulate waste into valuable adsorbents for metal ions. Our method has the advantage of aqueous solution fabrication under mild conditions without the use of high-temperature hydrothermal methods and toxic chemical reagents. Amyloid-mediated molecular engineering manipulates the phase transition of bovine serum albumin (BSA) on particulate waste surfaces, resulting in a remarkable ~3.1 times improvement in the adsorption capacity of fly ash, a typical industrial solid waste for gold ions after modification with the phase-transitioned BSA (PTB). The resultant adsorption ability was 69–1,980 times higher than those of conventional and emerging adsorbent materials such as ion exchange resins, activated carbon (AC), covalent organic frameworks (COFs), and metal-organic frameworks (MOFs). We further demonstrated the application of our PTB-modified materials in the recovery of precious metals from low-grade gold ore and electronic waste leachates. Consequently, this strategy could increase the value of waste materials nearly 27 times. In addition, this method is generally extendable to other conventional industrial adsorbents such as resin, clay, and Al₂O₃, and enhances their adsorption capabilities at least twofold. Overall, this work provides a simple and green approach for improving the adsorption performance of solid particles, and is expected to develop into a universal strategy for transforming waste particles into high-value-added products.

Controllable transportation of bubbles in surfactant or aqueous is very important in daily chemical products, food fermentation, mineral flotation and other fields. However, bubbles are mainly dominated by buoyancy and move upward in solution, which makes the manipulation of bubbles difficult. Although some progress has been made in controlling underwater bubbles, achieving continuous transportation and collection of underwater bubbles without relying on external forces is still a great challenge. To this end, we bionically designed a flexible polydimethylsiloxane (PDMS) porous surface with dual-Janus characteristics. Namely, a porous PDMS membrane integrating structural gradient and wettability gradient realizes the underwater anti-buoyancy unidirectional transportation of bubbles without external force input, and possesses the capability of underwater gas anti-buoyancy transportation and storage. This work provides inspiration and direction for the development and design of underwater gas transportation and storage devices and provides innovative thinking for the implementation of seabed carbon dioxide storage technology.

The photocatalytic CO₂ reduction reaction (CO₂RR) represents a promising solution to alleviate environmental and energy issues stemming from CO₂ emissions while simultaneously enabling the production of high-value multi-carbon fuels. However, the efficient generation of multi-carbon products remains challenging due to high kinetic barriers, sluggish C–C coupling processes, and intricate reaction pathways. This review provides a comprehensive overview of the latest advancements in synthesizing C₂₊ products through CO₂ photoreduction, highlighting the crucial role of active site design and the C–C coupling mechanism. Specifically, we emphasize the correlation between the structure of active sites and the key intermediates of C–C coupling, which is fundamental for achieving deep photoconversion of CO₂. Finally, we offer a glimpse into future challenges and prospects, outlining potential directions for the development of CO₂-to-multicarbon photoconversion, aiming to contribute novel insights to this exciting field.

The measurement of amino acid and monoamine neurotransmitters (NTs) in serum plays a central role in the identification and monitoring of clinical panic disorder (PD). However, the strong polarity and chemical heterogeneity of NTs make direct extraction and rapid detection extremely challenging. Herein, we developed a strategy that integrated solid phase extraction based on magnetic Fe₃O₄ coated with polydopamine (Fe₃O₄@PDA) and direct analysis of mass spectrometry in real time (DART-MS) for quantification of 10 NTs. We systematically investigated the optimal conditions of this strategy to achieve good accuracy and precision. Compared with existing magnetic solid phase extraction methods for NTs detection in biological samples, this strategy could adsorb more targets while having similar adsorption efficiencies, and the total process time was reduced by an average of 69.42%. We rapidly determined the metabolic abnormality of 6 types of NTs in the serum of PD patients and demonstrated their diagnostic accuracy. In addition, an outstanding feature of PD in which tryptophan was more metabolized by the KYN pathway and the 5-hydroxytryptamine pathway was inhibited could be elucidated by this strategy. Our results highlighted the potential ability of Fe₃O₄@PDA coupled with DART-MS to assist in the clinical diagnosis of PD.

The escalating utilization of nuclear energy and nuclear medicine raises concerns about the environmental impact of radioactive iodine, necessitating the development of effective iodine adsorbents, especially under a real-world scenario with extremely low iodine concentration and elevated temperature. Herein, we have presented the construction of a nitrogen-abundant two-dimensional (2D) halogen-bonded organic framework, XOF-TNP, characterized by exceptional crystallinity, thermal stability, and nitrogen-rich structures. XOF-TNP exhibits strong binding to iodine, thanks to the fact that iodine can be pre-enriched into the framework through N⋯I interactions. The nitrogen-rich framework and I⁺ synergistically have extremely high binding force to iodine, enabling the rapid and efficient capture of iodine in both vapor and solution phases, with significant recyclability. Further flow-through adsorption experiments using an XOF-TNP-packed column achieve 99% iodine removal from hexane and aqueous solutions, surpassing traditional activated carbon. This highlights its potential for environmental remediation. XOF-TNP enables the development of a novel rewritable security paper, utilizing its iodine adsorption properties to encrypt and decrypt QR codes. This research expands the application scope of halogen-bonded organic frameworks, providing insights into the design of materials for environmental remediation and security applications.

Compared with the conventional strategies of electronic and/or steric perturbation, catalytic olefin polymerization modulated by light irradiation or metal-metal cooperativity effect is a fascinating challenge that attracts considerable attention in the academic community. In this context, we design a strategy that could employ both effects to influence the polymerization process. Some dinuclear salicylaldimine and α-imino-ketone nickel complexes bearing a stiff-stilbene bridge were prepared, which could transfer between (E)-isomers and (Z)-isomers under ultraviolet irradiation. This isomerization can tune the electronic, steric and metal-metal cooperativity effects of the nickel catalysts. In this way, the catalytic activity, as well as polymer microstructures including molecular weight and branching density can be modulated in ethylene polymerization and copolymerization reactions. This strategy is generally applicable to other olefin polymerization catalytic systems and other types of transition metal mediated catalysis.

The Reformatsky reagent derived from ethyl bromoacetate circumvents the challenge associated with the direct regio- and enantioselective iridium-catalyzed allylic alkylation with an unstabilized aliphatic ester enolate. Notably, this work represents the first example of using a Reformatsky reagent in a metal-allyl reaction, which permits the direct construction of enantioenriched β-stereogenic homoallylic esters without preactivation of the pronucleophile or post-reaction modification of the product (e.g., thermal decarboxylation of a 1,3-dicarbonyl). Moreover, the process allows the coupling of a broad range of sterically and electronically diverse electrophiles bearing aryl, heteroaryl and alkenyl derivatives, including the significantly more challenging alkyl-substituted allylic carbonates. The versatility of the ester product is exemplified by a series of functional group manipulations and the development of a concise and efficient enantioselective total synthesis of the natural product, (+)-descurainolide A. Finally, mechanistic studies indicate that the zinc enolate behaves as a soft nucleophile that undergoes outer-sphere alkylation.

Currently, the application of synthetic biology to artificially manipulate and utilize organisms for the synthesis of desired products such as nanomaterials with excellent fluorescence properties is attracting considerable attention. However, it is still difficult to obtain designed products efficiently due to insufficient knowledge of the biosynthetic mechanisms. The thioredoxin (TRX) and glutathione (GSH) pathways are generally conserved thiol-reductase systems that protect organisms from oxidative stress and are involved in selenium (Se) metabolism. In this study, we revealed the pivotal role of cytoplasmic TRX pathway in regulating the metabolism of Na₂SeO₃ during the live-cell synthesis of cadmium-selenium quantum dots (CdSe QDs) in Saccharomyces cerevisiae by regulating the expression level of genes related to TRX pathway and measuring the intracellular content of selenocysteine (SeCys). The determination of SeCys metabolism in yeast with GSH pathway-related genes deleted demonstrated that the TRX pathway played a more significant role in SeCys metabolism than GSH pathway. A 6.4-fold enhancement in the synthetic yield of CdSe QDs was achieved through the overexpression of TRX pathway-related genes, improvement of synthetic procedure, and supplementation of GSH based on the understanding of biological metabolism. Exploring the mechanism of CdSe QDs live-cell synthesis facilitates the precise manipulation of biological processes for the synthesis of inorganic nanomaterials.

Organic electrode molecules hold significant potential as the next generation of cathode materials for Li-ion batteries. In this study, we have introduced a multi-objective active learning framework that leverages Bayesian optimization and non-dominated sorting genetic algorithms-II. This framework enables the selection of organic molecules characterized by high theoretical energy density and low gap (LUMO-HOMO) (LUMO, lowest unoccupied molecular orbital; HOMO, highest occupied molecular orbital). Remarkably, after only two cycles of active learning, the determination of coefficient can reach 0.962 for theoretical energy density and 0.920 for the gap with a modest dataset of 300 molecules, showcasing superior predictive capabilities. The 2,3,5,6-tetrafluorocyclohexa-2,5-diene-1,4-dione, selected by non-dominated sorting genetic algorithms-II, has been successfully applied to Li-ion batteries as cathode materials, demonstrating a high capacity of 288 mAh g⁻¹ and a long cycle life of 1,000 cycles. This outcome underscores the high reliability of our framework. Furthermore, we have also validated the universality and transferability of our framework by applying it to two additional databases, the QM9 and OMEAD. When the training dataset of the model includes at least 500 molecules, the determination of coefficient essentially reaches approximately 0.900 for four targets: gap, reduction potential, LUMO, and HOMO. Therefore, the universal framework in our work provides innovative insights applicable to other domains to expedite the screening process for target materials.