Science China Chemistry最新文献

Ti₃C₂T_x MXene anodes for lithium-ion batteries (LIBs) frequently face the significant challenge of low energy storage performance because of their sluggish ion transport kinetics, which is closely related to the surface termination chemistry, particularly for the electrochemical undesired hydroxyl terminations. Herein, we propose a melamine (MA) shielding strategy to the hydroxyl terminations of Ti₃C₂T_x MXene (Ti₃C₂T_x/MA) for optimizing its Li⁺ transport and storage behavior, enabling high-performance energy storage of Ti₃C₂T_x. The density functional theory calculations disclose that the electron-rich nitrogen atoms within the triazine ring of MA notably enhance the Li⁺ adsorption capacity at the interfaces of MA and hydroxyl terminations of Ti₃C₂T_x/MA, and meanwhile also increase the distance between Li⁺ and the hydroxyl terminations. This purposive modification of the electrochemical environment reduces the hindrance posed by the hydroxyl terminations on Li⁺ transport and improves the Li⁺ diffusion kinetics, thereby enhancing the electrochemical performance. As a consequence, the as-designed Ti₃C₂T_x/MA as an anode for LIBs achieves a high-rate capability (3 times higher than that of the pristine Ti₃C₂T_x at 10.0 A g⁻¹), and excellent cycling stability (220.1 mAh g⁻¹ at 2.0 A g⁻¹ over 1000 cycles), as well as a wide temperature operation range (−20 °C to 50 °C). This work offers a novel and straightforward strategy to boost the electrochemical performance of MXenes for practical energy storage applications.

The miniaturization of semiconductor devices is constrained by the resolution-sensitivity-roughness (RLS) trade-off in photoresists. Tin-oxo clusters (TOCs) provide a chemically tunable platform where performance can be effectively modulated through ligand design. Although alkenyl groups promote cross-linking and fluorinated moieties enhance both solubility and etch resistance, their cooperative function within one molecular framework remains unclear. Here, we design a series of Sn₂-oxo clusters with ligands containing both alkenyl and trifluoromethyl (–CF₃) groups (Sn₂-1), only alkenyl (Sn₂-2), and only–CF₃ (Sn₂-3). In electron beam lithography (EBL), Sn₂-1 achieves higher resolution (13.56 nm) and lower line-edge roughness (LER) than Sn₂-2, despite a moderate sensitivity cost. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) reveal a dual intramolecular mechanism: the–CF₃ group withdraws electron density from the alkenyl moiety, suppressing uncontrolled cross-linking, while the cleaved fluorine radicals are locally scavenged by the adjacent carbon-centered radicals. This work establishes a ligand-design strategy based on alkenyl-fluorine synergy effects, providing critical insights for advancing high-performance TOC-based photoresists.

Energy-efficient separation of xylene isomers remains a long-standing challenge owing to their nearly identical physicochemical properties. Here we report a double-bowl, sandwich-type palladium molecular cage (Pd₃L₂) assembled from a bowl-shaped phosphangulene oxide ligand and (bpy)Pd^II (2,2′-bipyridine) centers, featuring a hydrophobic and shape-persistent cavity. Benefiting from precise size and shape complementarity, Pd₃L₂ exhibits exceptional selectivity for o-xylene (OX) over its isomers (m-xylene, MX; p-xylene, PX), enabling efficient separation from an equimolar OX/MX/PX mixture and affording OX with a purity of up to 90%. Beyond xylene isomer separation, Pd₃L₂ also preferentially encapsulates benzene (Bz) over cyclohexane (Cy), allowing effective benzene separation under mild conditions. By integrating host-guest molecular recognition with a simple extraction strategy, this recyclable molecular cage provides an efficient and versatile platform for the separation of structurally similar aromatic hydrocarbons, highlighting the potential of molecular cages as energy-saving alternatives to conventional distillation-based processes.

Controlling the assembly of multinuclear silver-sulfur (Ag-S) clusters remains a major challenge due to the difficulty of precise sulfur coordination. Herein, we report a sulfide-controlled strategy using potassium isobutyl xanthate as a slow-release sulfur source to achieve selective formation of two structurally distinct clusters—Ag₅₄, featuring a three-shell core-shell architecture with 13 sulfide ions, and Ag₅₀, exhibiting a spindle-shaped framework with 8 sulfide ions— within a single reaction system of silver trifluoromethanesulfonate and TabHPF₆ (Tab = 4-(trimethylammonio)benzenethiolate). Modulating the sulfide concentration enables high-purity crystallization and efficient separation of both clusters and triggers a topological transformation of Ag₅₀ into Ag₅₄, highlighting the pivotal role of sulfide ions in directing cluster topology. Polymer composite films incorporating these clusters demonstrate significantly enhanced third-order nonlinear optical responses compared to solution-phase counterparts. This work establishes a generalizable approach for sulfide-driven structural control of metal-sulfur clusters and provides a foundation for designing Ag-S materials with tunable structures and optoelectronic properties.

Electrochemical precision synthesis technology, as a green and efficient synthetic approach, demonstrates tremendous potential in the production of high-value-added chemicals. However, reaction kinetics issues remain a critical bottleneck constraining its development, including difficulties in reactant adsorption and activation, slow protonation and electron transfer rates of intermediates, the impact of competing reactions on selectivity, and mass transfer limitations. This paper systematically reviews core reaction kinetic issues in the electrochemical precision synthesis of high-value-added organic chemicals, providing an in-depth analysis of their underlying mechanisms and summarizing recent advances in novel electrode materials, reaction condition optimization, reactor design, and operando characterization techniques. Furthermore, by integrating industrial application cases and technology readiness assessments, it identifies current technical challenges for large-scale production and outlines future development trends, particularly in innovative directions such as artificial intelligence (AI)-assisted optimization, green electrolyte development, and sustainable pathways. This paper aims to provide theoretical references and technical support for further research and application of electrochemical precision synthesis technology.

Non-centrosymmetric (NCS) structures are sought-after crystalline materials due to their symmetry-dependent properties and wide application potential. However, designing NCS materials in a rational and efficient manner presents a significant challenge. This work presents a strategy centered on the synergistic and parallel alignment of functional building groups. It is implemented by their careful selection and assembly to achieve a highly parallel architecture, driving the structure toward NCS. Based on this strategy, extending from the single-group (LiHC₂O₄·H₂O) to composite functional-group structural transformation, a series of novel materials were obtained. These series include three CS materials, Cs₄[B₃O₃(OH)(C₂O₄)₂](NO₃)₂ and A₄[B₃O₃F₂(OH)(C₂O₄)](NO₃)₂ (A = K, Rb), as well as two NCS materials, A₃[B₃O₃F₂(OH)(C₂O₄)][B₃O₃F₂(OH)₂] (A = K, Rb). Adjustments and optimization of the functional group arrangement in Cs₄[B₃O₃(OH)(C₂O₄)₂]-(NO₃)₂ enabled the A₄[B₃O₃F₂(OH)(C₂O₄)](NO₃)₂ family to exhibit significantly larger birefringence (0.182–0.172@546 nm). Further adjustment and optimization of A₄[B₃O₃F₂(OH)(C₂O₄)](NO₃)₂ enabled the transformation into the NCS structure A₃[B₃O₃F₂(OH)(C₂O₄)][B₃O₃F₂(OH)₂], while also exhibiting a moderate SHG response (0.7–0.4 × KDP) and a deep-UV cutoff edge (192–194 nm). The structural transformation achieved through this strategy, extending from single to composite modules, establishes a general design principle for synthesizing function-oriented crystalline materials.

In this work, we have synthesized and characterized three heterometallic [Ni₄(OH)₃(NO₃)₃(SiW₉O₃₄)@Ag₃₉(^tBuC≡C)₂₄(NO₃)₆](NO₃) (Ag₃₉Ni₄), [Co₄(OH)₃(NO₃)₃(SiW₉O₃₄)@Ag₃₉(^tBuC≡C)₂₄(NO₃)₆](NO₃) (Ag₃₉Co₄) and [Cu₃(OH)₂O(SiW₉O₃₄)@Ag₄₂(^tBuC≡C)₂₇(NO₃)₃Cl](NO₃)₃·CH₃CN (Ag₄₂Cu₃) clusters and one homometallic [(SiW₉O₃₄)@Ag₄₄(^tBuC≡C)₂₆Cl₈]·CH₃CN (Ag₄₄) cluster using lacunary polyoxometalates (POMs) as anionic templates under facile solvothermal conditions. Structural analyses reveal their similar core-shell architectures featuring a POM anionic template and a bowl-shaped silver shell stabilized by surface organic alkynyl (^tBuC≡C⁻) ligands. Various physicochemical and catalytic studies have characterized their temperature-dependent photoluminescence, photothermal conversion performance, and catalytic activity. Particularly, the enhanced catalytic performance towards 4-nitrophenol reduction is observed in the heterometallic cluster-catalyzed systems, where Ag₃₉Ni₄, Ag₃₉Co₄, and Ag₄₂Cu₃ exhibit higher catalytic activity than Ag₄₄. Such remarkable catalytic enhancement reveals that incorporating heterometal atoms into Ag clusters will be a feasible strategy to adjust the catalytic performance of POMs-templated Ag clusters.

Effective in vivo uranium clearance and mitigation of its radiation damage are crucial for the safety of uranium-exposed workers and residents, yet remain challenging. Current small-molecule drugs suffer from rapid metabolism and poor organ targeting, limiting their effectiveness in both preventive and long-term exposure scenarios. Nano decorporation agents, despite their prolonged in vivo retention due to nanoscale size and physico-chemical properties, encounter limitations such as restricted long channels and mismatched coordination geometry of chelating sites, which impede rapid and selective uranyl binding under physiological conditions. This study employs discrete metal-organic polyhedra (MOPs) to achieve a dense grafting and flexible arrangement of carboxylic acid chains, aiming to attain collaborative coordination of uranyl ions on the faces of tetrahedral structures. These MOPs selectively capture uranyl at low concentrations in vitro and show superior in vivo removal efficiency compared to clinical drugs and currently reported nano agents in both prophylactic and delayed treatments, where higher grafting density of carboxyl chains leads to greater decorporation efficiency. This work underscores the potential of MOPs in advancing nanomedicine for nuclear emergencies.