Owing to their unique architectures, calix[4]arenes exhibit considerable potential in molecular recognition, catalysis, sensing, nanotechnology, and biotechnology. However, the exploration of their structure–function relationships has been constrained by the challenge of synthesizing these molecules in optically pure form. Existing asymmetric strategies include: (1) direct asymmetric macrocyclization; (2) asymmetric post-assembly modification; and (3) asymmetric substitution to increase the conformational inversion barrier. Although significant progress has been achieved in the enantioselective synthesis of inherently chiral calix[4]arenes, there remains an urgent need for the asymmetric divergent synthesis of inherently chiral calix[4]arenes fused with bicyclic heteroaromatic rings. Palladium-catalyzed cycloimidoylation of functionalized isocyanides represents a powerful strategy for constructing N-heterocyclic frameworks. This approach has proven effective for enantioselective desymmetrization of symmetric isocyanides via C(sp²)–H activation, affording N-heterocycles with central, planar, axial, and helical chirality. Inspired by our ongoing interest in inherently chiral molecules, we envisioned that Pd-catalyzed cycloimidoylation could be strategically applied to construct inherently chiral calix[4]arenes with extended aromatic systems. Herein, we report an efficient approach for the enantioselective synthesis of inherently chiral quinoline-fused calix[4]arenes via palladium-catalyzed asymmetric C−H cycloimidoylation. The cyclization strategy of forming a six-membered heterocyclic ring employs readily available calix[4]arene derived isocyanides and aryl iodides as coupling partners under mild conditions with low catalyst loading, and a wide range of calix[4]arenes with extended aromatic systems were obtained with high yields and excellent enantioselectivities (up to >99% ee). Notably, the double C(sp²)–H imidoylative annulation of calix[4]arene-derived bisisocyanides affords unique inherently chiral calix[4]arenes embedded with bis-phenanthridine units. Density functional theory (DFT) calculations reveal the origin of the enantioselectivity during the C(sp²)−H imidoylative cyclization process. This methodology offers versatile access to structurally intriguing inherently chiral calix[4]arenes for further functionalization.

High quality light-absorbing layers with matched band gaps of sub-cells are crucial for achieving high power conversion efficiency (PCE) in the perovskite/organic tandem solar cells (PO-TSCs). In this work, we systematically optimized the band gaps of wide-bandgap perovskite layer (1.73–1.85 eV) and narrow-bandgap organic active layer (1.34–1.38 eV). An asymmetric small-molecule acceptor, namely SY2 (two F atoms and two Cl atoms), is introduced into the PM6:BTP-eC9 blend to enhance the light absorption, form the fibril network morphology, and facilitate exciton dissociation and transport. By precisely integrating a 1.80 eV perovskite sub-cell and a 1.34 eV ternary organic sub-cell, we achieved a champion PCE of 25.47% for the PO-TSCs based on the well-matched short-circuit current density. Besides, the optimized devices exhibited outstanding long-term stability. Our findings highlight the importance of band gap matching between front and near sub-cells in reducing recombination loss for high-performance tandem solar cells.

Transition-metal-catalyzed oxidative cross-dehydrogenative coupling (CDC) reactions represent an attractive strategy for the direct construction of C–C and C–X (X = heteroatom) bonds, owing to their inherent atom and step economy. This strategy has been recently extended to the B–H/C–H cross-dehydrogenative coupling of carboranes with arenes. However, such transformations typically either rely on the assistance of directing groups or are restricted to intramolecular processes. Herein, we report a palladium-catalyzed direct cross-dehydrogenative coupling between the B–H bond of carboranes and the C–H bond of (hetero)arenes, which affords B(9)-arylated products of o/m-carboranes in good to excellent yields with a broad substrate scope. Notably, this methodology is not limited to simple benzene rings but also delivers high yields with polycyclic aromatic hydrocarbons, five-membered heterocycles, and benzo-fused five-membered heterocycles. Control experiments reveal that B–H activation occurs preferentially over C–H activation. The high reactivity of carboranes toward Pd(II) and their steric hindrance are the keys to this successful transformation, suppressing the formation of (hetero)arene and carborane homo-coupling products, respectively.

To tackle some shortcomings of the classic Fischer indole synthesis employing aldehydes as starting materials, we report herein a reductive Fischer-type indole synthesis based on carboxylic acids. This method comprises a tandem sequence involving B(C₆F₅)₃-catalyzed hydrosilylation of carboxylic acids with Et₃SiH to generate the corresponding O,O-disilyl acetals, p-TsOH-mediated transamination with arylhydrazines to form hydrazones, and a late-stage Fischer indole cyclization. In this manner, carboxylic acids act as surrogates of aldehydes. Using this one-pot protocol, a series of 3-substituted indoles, including 3,4-, 3,5-, and 3,6-disubstituted indole derivatives have been synthesized. The utility of this protocol is demonstrated by the efficient synthesis of the versatile natural product 3-methylindole, the key intermediate in the commercial production of the antidepressant drug Vilazodone (Viibryd), and the core scaffold of one of the most frequently prescribed agents for the treatment of hypercholesterolemia—all from inexpensive, commercially available carboxylic acids and arylhydrazines. The one-pot reaction tolerates several functional groups such as halogen (F, Cl, Br, I), MeO, CN, and CF₃, which are either key moieties for the development of medicinal and agrochemical agents, or can be used as a handle for the further elaboration of the indole products, as demonstrated by the two-step synthesis of a tetracyclic indole derivative.

Directing-group (DG)-free enantioselective functionalization of C(sp³)–H bond has emerged as a powerful tool for the late-stage diversification in synthetic and medicinal chemistry. Herein, we have developed an enantioselective triple C–H bond functionalization method via asymmetric migratory allylic substitution of 1,2-enols enabled by palladium catalysis. The robust nature of the migratory allylic substitution strategy is reflected by a broad scope of both electrophiles and nucleophiles with the control of chemo-, regio- and enantioselectivity. This migratory alkylation method is redox-neutral, with three C(sp³)–H bonds being oxidized for the alkylative functionalization and the original enol unit being reduced simultaneously. Mechanistic studies suggest that each one-carbon migration consists of the sequential β-H elimination and migratory insertion to form a new π-allylpalladium species with the intermediacy of the diene-palladium complex. This method was successfully applied for the synthesis of biologically active substances, (+)-Phenoxanol, (+)-Citralis, and (−)-Citralis Nitrile.

Cyclopropane serves as a pivotal structural motif in numerous pharmaceuticals, fuels, and natural products. Iron-containing heme enzymes have recently been extensively explored as biocatalysts for olefin cyclopropanation via electrophilic carbene transfer. However, mechanistic and structural constraints pose significant challenges for transforming electron-deficient olefins and modulating reactivity using these systems. Herein, we report the design of biocompatible biomimetic catalysts inspired by free radical reactivity, integrating heme-active iron porphyrin and axial ligands to study cyclopropanation of challenging electron-deficient olefins and transient radical regulation mechanisms. Owing to their electronic tunability, substituent-induced electronic effects were identified for the first time as dominating the catalytic activity of radical intermediates in cyclopropanation. The electron-withdrawing Fe^III(Cl)-CF₃ catalyst exhibited enhanced activity with a reaction rate of 4.86 x 10^–5 M·s^–1, reaching max 27.2 x 10^–5 M·s^–1 after system optimization. DFT calculations revealed that electron-withdrawing substituents stabilize transition states by generating strong Fe–C bonds through high positive charge localization on the central metal, thereby reducing energy barriers in rate-limiting steps. Additionally, the highly reactive α-C alkyl radicals generated post-reaction contribute substantially to the catalytic efficacy. As anticipated, [Fe^III(Cl)-TFMPP] demonstrated efficient cyclopropanation across diverse olefins (up to 99% yield and 99 : 1 dr).

The construction of functional and robust covalent organic frameworks (COFs) for gas separation, particularly for the efficient removal of CO₂ from propylene (C₃H₆), is both significant and challenging. Herein, thiadiazole-linked COFs were reported by postsynthetic modification (PSM) of hydrazone-linked COFs with Lawesson's reagent (LR). The as-prepared thiadiazole-linked COFs not only retain porosity and crystallinity but also enhance their chemical stability. Furthermore, both thiadiazole-linked COFs demonstrate excellent C₃H₆ adsorption capacity. Notably, TDA-Ta-ODH-COF exhibits higher C₃H₆ adsorption capacity, which can separate C₃H₆ from the C₃H₆/CO₂ mixture. Dynamic separation results at 298 K and 1 bar indicate that CO₂ first breaks through the bed at 80 min/g due to the higher adsorption affinity of C₃H₆. C₃H₆ is not detected until 100 min/g. Consequently, this process yields a polymer-grade C₃H₆ output of 2.01 mmol/g. In addition, TDA-Ta-ODH-COF also has the potential to separate polymer-grade C₃H₆ from a ternary mixture of C₃H₆/CH₄/CO₂ (1/1/1). The observed adsorption disparity originates from the abundant heteroatomic sites (N, O, S) in the thiadiazole-linked COFs, which exhibit distinct adsorption affinities for C₃H₆, CH₄, and CO₂. A suitable isosteric heat of adsorption (Q_st) provides sufficient driving force for selective capture while facilitating low-cost and efficient regeneration. This work presents a facile protocol for fabricating stable and functional COFs, providing references for gas adsorption and separation applications.

Although 1,4-Pd migration has been widely used for the functionalization of remote C−H bonds, intermolecular double C−H annulation via this strategy remains elusive. Furthermore, catalytic reactions involving 1,5-Pd migration are scarce due to competitive reductive elimination pathway. Herein, we report an intermolecular double C–H annulation of N-(2-bromophenyl)-2-phenylacrylamides with 1,n-diynes mediated by 1,4-Pd or sequential 1,4/1,5-Pd migrations. The reaction proceeds through sequential Heck cyclization, alkyl-to-aryl 1,4-Pd migration (or alkyl-to-aryl 1,4-Pd migration followed by aryl-to-aryl 1,5-Pd migration), dual alkyne insertion, and C–H activation, providing efficient access to both indolinone-substituted tricyclic frameworks and tetracyclic indolinones. The method exhibits excellent regioselectivity, and preliminary mechanistic studies support the proposed pathway.

Ligand-directed divergent synthesis (LDS) has emerged as a powerful chemical tool for the formation of miscellaneous molecular frameworks from common reactants. Consequently, the rational development of ligands is of great concern. Previously, N,N-ligands were shown to direct the reaction pathways of palladium(II)-catalyzed cascade cyclization of alkyne-tethered cyclohexadienones with acetic acid, thus forming two types of cis-hydrobenzofuran products. In this work, we have reported 6-methoxypyridine-benzoxazole ligand-directed palladium(0)-catalyzed hydroacetoxylative cyclization of alkyne-tethered cyclohexadienones with carboxylic acids, providing the structurally novel cis-hydrobenzofurans with high yields and broad substrate scope. In this process, carboxylic acids not only serve as hydrogen sources but also act as nucleophiles. Mechanistic investigations and DFT calculations revealed that this reaction was a palladium(0)-catalyzed hydroacetoxylative cyclization, the hydrogen source was from the proton of the carboxylic acid and the low σ-donor ability of 6-methoxypyridine-benzoxazole ligand proved to be crucial for palladium-catalyzed hydrogen transfer from carboxylic acids to alkynes and nucleophilic acetoxylation of the palladium enolate.

A practical and transition-metal-free synthesis of α-bromo/chloro ketones is developed via sequential 1,2-migration and oxidation of alkynyl tetracoordinate boron species under mild conditions. This method employs readily available N-bromosuccinimide (NBS) and N-chlorosuccinimide (NCS) as halogen sources, achieving high efficiency (up to 95% yield) with operational simplicity. The reaction demonstrates broad functional group tolerance, offering a versatile platform for α-halo ketones.

The 1,2-cis-2-amino-2-deoxyglycoside represents a critical structural motif in numerous bioactive natural products and pharmaceuticals, yet its stereoselective synthesis remains a long-standing challenge. Building on our previous ZnI₂-mediated methodology for constructing 1,2-cis-2-azido-2-deoxy glycosidic linkages, we herein report systematic refinements that substantially enhance the versatility and efficiency of this approach. Key advancements include: (i) Substitution of zinc iodide with zinc triflate [Zn(OTf)₂], a superior Lewis acid catalyst that expands substrate scope to include sterically hindered and electronically deactivated glycosyl acceptors; (ii) Development of a novel glycosyl donor platform superseding the conventional 4,6-O-TIPDS/3-O-TIPS protection patterns, enabling streamlined post-glycosylation deprotection sequences for iterative glycan assembly. These methodological improvements effectively address prior limitations in functional group compatibility and synthetic scalability. Leveraging this optimized protocol as the cornerstone synthetic strategy, we achieved the total synthesis of the Acinetobacter baumannii capsular polysaccharide (CPS) K88 pentasaccharide repeating unit, a structurally complex target containing two consecutive 1,2-cis glucosaminide linkages. This synthetic milestone demonstrates the robustness of our methodology and furnishes essential molecular tools for subsequent immunological investigations of this clinically significant pathogen.

The field of chemistry, across its various subdisciplines, has been significantly enriched by advances in understanding carbon intermediates since the 19th century. Among them, carbenes have evolved from transient intermediates to versatile molecular tools, yet integrating luminescence and stimuli-responsiveness in a single system remains a challenge. We report a lithium-bridged carbene-amide hybrid achieves this bifunctional integration. This architecture exhibits intense fluorescence (luminescence efficiency: Φ_PL = 85%) and undergoes reversible two-electron cycling among carbene-amido, radical intermediate, and delocalized carbocation states via stepwise single-electron transfers, as demonstrated by crystallographic, spectroscopic, and computational analyses. The asymmetric redox pathway involves N-centered radical formation during oxidation but bypasses this intermediate during reduction, enabling dynamic interconversion. This redox transformation facilitates the direct and reversible conversion between the carbene and carbocation species in a single mechanistic step. Structural studies reveal lithium coordination geometry and charge delocalization underpinning stability. Bridging exciton engineering and dynamic materials science, the work opens avenues for smart molecular technologies in precision synthesis and optoelectronics.

Photodetectors (PDs) are core components in imaging, health monitoring and environmental sensing systems. As electronics become increasingly integrated into wearable, soft and bio-interfacing platforms, there is growing demand for photodetectors that combine mechanical stretchability, low power consumption and optical sensitivity. Unlike strain-accommodating strategies using serpentine metal traces or rigid islands, intrinsically flexible and stretchable photodetectors are constructed from fully deformable active layers, electrodes and substrate. This ensures seamless mechanical conformity and long-term biomechanical compatibility, enabling stable light detection even under stretching, bending, or twisting, thereby meeting the requirements of on-skin, soft robotic, and subdermal applications. Recent advances in materials design, from stretchable conjugated polymers to conductive, deformable electrodes, have greatly improved the performance and durability of OPDs. Meanwhile, progress in device engineering, including solution-based processing, scalable fabrication, and array integration, has facilitated the construction of high-resolution stretchable photodiode arrays for multimodal sensing. These innovations collectively broaden the functional landscape of OPDs. This article highlights recent innovations in flexible and stretchable organic photodetectors, focusing on material design, morphology control, fabrication strategies, and emerging applications in wearable optoelectronics. Particularly, we analyze how molecular engineering approaches enhance both mechanical compliance and optoelectronic properties, discuss manufacturing techniques that enable scalable production, and highlight implementation examples in health monitoring, artificial vision, and human-machine interfaces. Finally, we address key challenges and future research directions, including the development of sustainable processing methods, the creation of next-generation wearable optoelectronic systems with enhanced functionality, and the establishment of standardized measurement protocols for accurately characterizing the performance of stretchable OPDs under operational conditions.

Rogers and co-workers first adhered photodetectors to human skin, introducing the concept of epidermal electronics.^[1] Building on this vision, Someya's group in 2018 fabricated self-powered ultraflexible sensors capable of conforming not only to the skin but also to dynamic organs such as the heart.^[11] In 2021, they further integrated multiple photodiodes to realize a self-powered photoplethysmography (PPG) sensor.^[47] In parallel, Kippelen and colleagues in 2020 employed the conventional poly(3-hexylthiophene-2,5-diyl) (P3HT): Indene-C60 bisadduct (ICBA) active layer system to fabricate large-area flexible OPDs, achieving performance comparable to silicon photodetectors in all aspects except response time.^[10] In 2022, Yu et al. proposed an innovative device fabrication strategy in which the photoactive film formed a micromesh structure, thereby enhancing intrinsic stretchability without compromising electrical performance.^[13] In the following year, an elastomer–semiconductor–elastomer stacked configuration was reported, enabling stretchable OPDs suitable for imaging applications.^[58] Progress continued in 2024, Lin et al. utilized colloid processing to realize high-performance flexible OPDs, demonstrating superior in-situ detection of trace pollutants in water.^[60] In 2024, Huang's group regulated the molecular ordering of small-molecule acceptors to extend OPD applications to large-area flexible devices and by 2025 advanced molecular engineering of acceptors to further broaden the application space of flexible OPDs across diverse fields.^[18-19] Chen's group in 2024 significantly advanced the optical communication application of flexible OPDs by introducing a narrow-band acceptor.^[56] In the following year, relying on high-performance flexible visible-blind near-infrared organic photodetectors, a flexible photonic contactless human-machine interface has been developed, which significantly expands the applications of flexible OPDs.^[80]

Covalent organic frameworks (COFs), characterized by their reticular chemistry with covalent bonds between organic building blocks, have emerged as the state-of-the-art membrane materials in numerous applications. Compared to conventional polymer membranes, COF membranes hold superior capacities in pushing the boundary of separation performance with high permeability and selectivity, due to their merits of highly tunable and ordered crystalline pore structure, programmable chemistry, high porosity, and excellent stability. Over the past decade, substantial advances in material design and application exploration of COF membranes have sparked ever-increasing research attention. To offer insightful implication for researchers from different fields, it is highly valuable to systematically summarize the recent advancements of COF membranes from the perspective of nanochannel structure and chemical property, two of the most important indicators to dictate their separation performance. In this review, we discuss recent progress in the mainstream fabrication methods of COF membranes, mainly including interfacial polymerization, in-situ growth, and nanosheets assembly and stacking. Then, we emphasize how to engineering nanochannel structure and chemical property of COF membranes in these three kinds of fabrication methods, as well as highlight their potential application in many areas such as ion/molecule sieving, gas separation and osmatic energy harvesting. Finally, some unsolved challenges and future perspectives in this field will be discussed, inspiring for the design and synthesis of advanced COF membranes.

In 2011, Dichtel and coworkers achieved in-situ growth of highly ordered COF thin films via solvothermal methods, marking the emergence of COF membrane materials.^[1] In 2017, Banerjee's group reported liquid-liquid interfacial polymerization of COF membranes via Schiff-base condensation.^[2] In 2018, Wang's group leveraged polymer membrane design principles to construct COF separation layers on porous polymeric substrates through interfacial polymerization.^[3] In 2020, Jiang's group developed monolayer NUS-9 nanosheets and assembled COF membranes.^[4] They subsequently developed multiple strategies for fabricating COF separation membranes, focusing on precise regulation of nanostructure to enhance separation performance. In the same year, Zhao's team reported the fabrication of two-dimensional COF membranes for gas separation.^[5] Then they advanced the development of high-performance responsive membranes. In 2021, Sun's research focused on mass transport mechanisms in COF nanofluidic membranes, investigating the relationship between structure and separation performance.^[6] In 2022, Tang's research group proceeded to develop ultrathin COF membranes for the osmotic energy conversion through interfacial polymerization.^[7] In 2023, Liu's group began preparing COF membranes through modulated interfacial polymerization, primarily for separation in water environments or organic solvents with smart responsiveness.^[8] In the same year, Wang developed a solid-liquid interfacial method for highly oriented COF membranes, contributing to the design of COF membranes with tunable properties for applications in electronics and energy applications.^[9] Given the abundance of distinguished studies on COF separation membranes, this timeline aims to highlight representative breakthroughs instead of providing an exhaustive historical record. These breakthroughs have collectively established a foundational framework for the design and synthesis of next-generation high-performance COF separation membranes.