Science China Chemistry最新文献

As the smallest fused hydrocarbon and one of the most strained carbocycles, bicyclo[1.1.0]butane (BCB) undergoes a wide array of strain-releasing transformations, thereby exhibiting a rich and varied chemical profile. Although BCBs have been synthesized and studied for over 60 years, its potential as a versatile building block for expanding chemical space has remained largely underexplored. Recently, the emergence of diverse activation strategies, such as photocatalysis, boryl radical catalysis, Lewis/Brønsted acid catalysis, palladium catalysis, Lewis base catalysis, and radical relay strategies, has revolutionized BCB chemistry into a powerful toolbox for expanding the chemical space of scaffold-diverse molecules, with a particular focus on cyclobutane, cyclobutene, and bicyclo [n.1.1]alkane scaffolds. In this review, we highlight the latest advancements in the divergent transformations of BCBs to construct cyclobutyl-decorated architectures from common precursors, with a particular emphasis on elucidating the reaction mechanisms. The content is organized based on key regulatory factors for product divergent formation. It is anticipated that this review will stimulate increased interest among researchers in integrating the concept of controllable divergent synthesis into BCB chemistry. By doing so, it is expected to further unlock the potential of BCBs in expanding molecular space and to extend the reach of BCB chemistry into a wider array of synthetic applications.

Hard carbon (HC) remains the most commercially viable anode for sodium-ion batteries, yet its low initial Coulombic efficiency and unstable solid electrolyte interphase (SEI) hinder long-term performance. Electrolyte engineering offers a promising strategy to regulate SEI chemistry, enhancing interfacial Na⁺ transport and interphase stability. However, the respective roles of solvents and anions in tailoring the SEI on HC remain elusive. Here we propose a “revitalization” strategy to clarify the synergistic influence of solvent and anion chemistry by systematically evaluating three electrolytes: 1.0 M NaPF₆ in EC/DMC, 1.0 M NaPF₆ in diethylene glycol dimethyl ether (NaPF₆-G2), and 1.0 M sodium trifluoromethanesulfonate in G2 (NaOTF-G2). Combined experimental and theoretical analyses reveal that weak Na⁺-G2 interactions permit more anions to enter the primary solvation shell, facilitating the formation of an inorganic-rich SEI that promotes high ionic conductivity and redox kinetics. Additionally, the preferential decomposition of OTF⁻-anions results in a uniform and robust SEI. As a result, HC anodes cycled in NaOTF-G2 deliver a reversible specific capacity of ~200 mAh g⁻¹ over 3000 cycles. Furthermore, a Na₃V₂(PO₄)₃||HC pouch cell incorporating this optimized electrolyte achieves a capacity retention of 81% at −40 °C. This work provides molecular-level insights into electrolyte design principles and highlights the critical role of solvation structure in enabling durable low-temperature sodium storage.

Enantioselective C-H functionalization has emerged as an efficient and transformative tool for constructing complex chiral molecules with exceptional step- and atom-economy. While this field was historically dominated by 4d and 5d transition metal catalysts, recent attention has shifted toward cobalt—an earth-abundant, cost-effective 3d transition metal with unique reactivity. Over the past few years, remarkable progress has been achieved in cobalt-catalyzed enantioselective C-H functionalization, primarily through three catalytic systems: (1) low-valent cobalt(I) catalysis, (2) cyclopentadienyl cobalt(III) catalysis, and (3) in situ generated cobalt(III) catalysis. This review provides a comprehensive survey of all reported asymmetric cobalt-catalyzed C-H activations proceeding through inner-sphere mechanisms, providing a systematic analysis of synthetic methodologies, reactivity patterns, origins of stereocontrol, mechanistic insights, and future opportunities.

The low phase-transition temperatures (T_pts) of structurally defined small molecules impose fundamental limitations on thermal stability in all-small-molecule (all-SM) systems. To overcome this, we designed and synthesized a dimeric donor, DM-2Cl, interconnected by a benzo[1,2-b:4,5-b′]dithiophene central unit side chain, and combined it with the giant molecule acceptor, BDY-β, to construct a conceptual all-giant-molecule (all-GM) system with enhanced solid-state T_pt. The DM-2Cl:BDY-β system suppressed morphology evolution under continuous thermal-annealing and demonstrated superior stability relative to the BDT-1S1Cl:Y6 reference. Crucially, optimized blend morphology and improved charge transport/extraction properties enabled the binary all-GM system to achieve a 15.56% PCE, which increased to 16.24% upon incorporating giant-molecule acceptor Se-giant-2F. This work paves the way to design dimeric donors, introducing new all-giant-molecule systems with high device efficiency and excellent thermal stability.

Palladium (Pd) has exceptional H₂ adsorption capacity and has been used as an adsorptive filler in mixed matrix membranes (MMMs) to enhance H₂ separation performance. However, a high Pd loading (20 wt%–60 wt%) is impractical due to cost. In this study, highly dispersed Pd nanoclusters are confined within the channels of mesoporous silica nanoparticles (MSNs), largely improving Pd atom utilization for facilitating H₂ transport while greatly reducing Pd loading content. MMMs prepared by mixing Pd@MSN with polybenzimidazole matrix, corresponding to a very low Pd loading of 0.6 wt%–3.0 wt%, exhibit much improved H₂/CO₂ separation performance. Specifically, an MMM containing only 2.5 wt% Pd shows mixed-gas separation performance of 302.6 barrer of H₂ permeability and 16.3 of H₂/CO₂ selectivity at 120 °C, largely surpassing the latest 150 °C upper bound. Our work demonstrates the enormous potential for applying Pd-based MMMs in gas separation by reducing noble metal loading by nearly two orders of magnitude.

The removal of trace plutonium (Pu) from uranium products and organic wastes during spent nuclear fuel reprocessing remains a critical challenge, resulting in excessive plutonium content in uranium products and waste organic liquid. Currently, most organic ligands with selective separation functions are lipophilic, while research on water-soluble, highly selective ligands is relatively scarce, and there are also few reports on the single crystal of these ligands coordinating with plutonium. Herein, a hydrophilic multiamide ligand, N,N,N′,N″,N″-hexaethyl-nitrilotriacetamide (NTAamideC2), was synthesized and evaluated for its Pu(IV) back-extraction efficiency under harsh conditions. Systematic experiments revealed that NTAamideC2 achieved >99% Pu(IV) back-extraction rate within 15 min across a wide nitric acid concentration range (0–5 M), even with elevated dibutyl phosphate (DBP ⩽20000 ppm). Remarkably, the separation factor (SFPu/U) reached 767 at 1.5 M HNO₃, demonstrating exceptional selectivity over uranium(VI). Spectrophotometric titration and DFT calculations confirmed the formation of 1:1 and 1:2 Pu(IV)-NTAamideC2 complexes, with logβ values of 7.42 ± 0.01 and 13.23 ± 0.02, respectively. Single-crystal X-ray diffraction analysis of {[Pu₂(H₂O)₂(NTAamideC2)₄](H₂O)₂(NO₃)(ClO₄)₇} revealed a nine-coordinated PuO₇N₂ geometry, where two NTAamideC2 molecules bind via six O and two N atoms. Compared to conventional agents (AHA/HSC), NTAamideC2 exhibited superior acid tolerance and selectivity, aligning with the CHON principle for sustainable nuclear waste management. This work provides a robust strategy for Pu(IV) removal in uranium purification cycles and advances fundamental insights into Pu coordination chemistry, offering significant potential for industrial nuclear fuel reprocessing.