Browse Articles

“Outside‐in” Design of Single‐Atom Catalysts: Linking Specific Peripheral Geometry to Defined CO ₂ Reduction Performance

Abstract The regulation of single‐atom catalyst (SAC) through microenvironment engineering, particularly via peripheral species, has recently garnered significant attention in the fields of materials science and heterogeneous catalysis. Nevertheless, establishing unambiguous structure‐property relationships for SAC, especially concerning peripheral effects, remains a significant challenge. Herein, we propose a strategy for the design of N‐doped carbon‐supported Fe SACs for CO 2 reduction reaction (CO 2 RR). Density functional theory(DFT) calculations reveal that installing five‐ or six‐membered ring in the outer shell modulates the electronic properties of the inner‐shell coordination N species, altering their electron transfer capabilities while fine‐tuning the d ‐ p coupling between the Fe center and adjacent N atoms. Notably, five‐membered rings induce stronger d ‐ p coupling compared to their six‐membered counterparts, leading to a higher Fe valence state. This electronic modulation optimizes the adsorption strength of key CO 2 RR intermediates (COOH* and CO*), enhancing catalytic performance for CO production. Extensive experimental studies corroborate these theoretical findings. The proposed “outside‐in” design strategy can be extended to Ni SACs, offering new insights into the exploration of highly efficient single‐atom centers through peripheral geometric effects.

Azine‐Pyridine Frame Generated Covalent Organic Frameworks and Self‐Polymerized Films

Abstract Engineering covalent organic frameworks (COFs) into industrializable films with inherent functionalities has remained a major challenge in synthetic chemistry. Here, through developing skeletal azine‐pyridine conformation, we present an effectual synthetic frame to convert a family of powdery COFs into self‐polymerized COFs films under green and ambient conditions. The active proton tautomerism in our azine‐pyridine frame offers a thermochromism, facilitating self‐polymerization of large‐area COFs films from ca. 10 nm to >30 µm thickness with outstanding chemical stability, industrializable processability, and mechanical strength. More remarkably, our azine‐pyridine‐based COFs first display various fresh properties, i.e., up to 1913 and 624 mg g −1 reducing capacities on ions of Au 3+  → Au 0 and Cr 6+  → Cr 3+ , 99.9% UV‐blue light shielding and 97.2% transmissivity of visible lights and 10‐fold increase in Zn battery lifetime. We expect that the azine‐pyridine synthetic frame will serve as a generalizable route to boost the development of reticular chemistry, environmental science, and nano‐electronics.

Si/Carbon‐dots with Surface N‐C Sites Promoting Proton and Electron Transfers in Oxygen Reduction Reaction

Abstract The oxygen reduction reaction (ORR) can proceed through either a two‐ or four‐electron pathway, both of which are important for a wide range of applications. The intermediate conversion of *O 2 ⁻ + H⁺ → *OOH recognized as the rate‐determining step in ORR, with its efficiency strongly dependent on the nature of active sites at the surface of a catalyst. Herein, Si‐supported carbon dots (Si‐CDs) are introduced as cocatalysts in a photocatalytic system, where their nitrogen–carbon sites play a pivotal role in lowering the energy barrier for *OOH formation by promoting proton and electron transfers, thus enhancing the H 2 O 2 production rate in ORR. This strategy is broadly applicable across a wide range of photocatalysts, both with and without use of sacrificial agents. The H 2 O 2 production rate for Zn 0.5 Cd 0.5 S (30 mg) increased from 13.0 to 40.9 µmol h −1 when 0.6 mg of Si‐CDs were added. In‐situ characterizations and theoretical simulations are conducted to reveal the reaction pathway and the reduced energy requirements for the *O 2 ⁻ + H⁺ → *OOH conversion. This study provides a unique example of overcoming a key barrier in ORR using a metal‐free catalyst and promotes potential applications in various fields.

Zwitterionic Heavier Pnictinidenes in Redox Catalysis

Abstract Herein, we describe a new class of zwitterionic heavier pnictogen species with bis ( N ‐heterocyclic carbene)borate as ligands, enabling the isolation of stable Sb and Bi species in multiple oxidation states. Computational analysis of zwitterionic pnictinidenes revealed their cationic character at the metal centre while holding unique electronic properties that contribute to their nucleophilicity and stability. These systems participate in oxidative addition and reductive elimination processes, and display redox catalytic activity in hydrodefluorination reactions, marking a unique example of cationic pnictinidene catalysing a redox transformation and providing reactivity beyond the constraints of pincer ligands. Additionally, we report on a novel dehydrogenative thiolation of silanes. This work expands the scope of low‐valent pnictogen chemistry, providing a novel platform for main group redox catalysis.

Chemically Recyclable Alternating Poly(thioether <i>‐alt</i> ‐ester)s with Tunable Properties Enabled by Substitution Effects and Stereochemistry

Abstract The development of innovative poly(ether‐ester)s with perfectly alternating ether and ester functionalities to overcome the trade‐offs between the polymer's depolymerizability and performance properties is in high demand for advanced material applications and sustainable development. Herein, we prepared a series of enantiopure cyclic thioether‐ester monomers bearing various pendant substituents by a facile “polycondensation‐depolymerization” strategy. The controlled ring‐opening polymerizations of these enantiopure monomers will afford stereoregular poly(thioether‐ alt ‐ester)s with structural diversity. The varieties of substituent size, position and stereo‐configuration provide the opportunity to systematically investigate polymerization kinetics and thermodynamics as well as structure‐properties relationship for the resulting poly(thioether ‐alt ‐ester)s. The strategic positioning of α‐, γ‐, and δ‐substituents coupled with stereoregular chain architectures and stereocomplex formation enables wide‐range modulation of the polymer's thermal and mechanical properties. A(hard)‐B(soft)‐A(hard) triblock thermoplastic elastomers with good mechanical performance and elastic recovery were also created by sequential polymerization. Of note, these polymers can be chemically recycled by either ring‐closing depolymerization or alcoholysis, with high monomer regeneration efficiency. The systematic investigation of substitution effects and structure‐property relationships in this work provides a molecular blueprint for designing novel chemically recyclable polymers with high performance.

Polyolefin‐based Multiblock Copolymers from Cascade ROMP‐RAFT Polymerization

Abstract Plastic disposal has become a serious environmental and social problem. Mechanical recycling of waste plastics is the most widely adopted strategy to address this issue, but if used to recycle mixed plastics, it usually requires the addition of amphiphilic block copolymers. Polyolefins account for almost half of all synthetic plastics, making them ubiquitous in the plastic waste stream. Within this perspective, polyolefin‐based multiblock copolymers are highly desirable, but they are difficult to access using traditional strategies. In this contribution, a cascade ring‐opening metathesis polymerization (ROMP) and reversible addition‐fragmentation chain transfer (RAFT) polymerization strategy was developed to prepare various polyolefin‐based multiblock copolymers with tunable polar segments and microstructures. Using this strategy, tunable amounts of the trithiocarbonate RAFT agents were installed in the polyolefin main chain via ROMP. Subsequent chain extension of various polar vinyl monomers via controlled RAFT polymerization formed various polyolefin‐based multiblock copolymers with high molecular weight and good physical properties. These multiblock copolymers were used to compatibilize and upcycle mixtures of high‐density polyethylene/polymethyl methacrylate (HDPE/PMMA) and high‐density polyethylene/polyethylene terephthalate (HDPE/PET).

Frank Tambornino

Modular Access to P(V)‐Stereogenic Compounds via Cu‐Catalyzed Desymmetrization of (Thio)Phosphonic Dichlorides

Abstract Chiral phosphorus(V) centers—particularly those bearing fully heteroatom‐substituted frameworks—are key stereochemical motifs in pharmaceuticals, nucleic acid therapeutics, and functional materials. However, their stereoselective construction remains a long‐standing challenge in synthetic chemistry. Here, we report a copper‐catalyzed desymmetrization strategy enabled by rationally engineered PIM ligands that affords broad and modular access to structurally diverse P(V)‐stereogenic compounds. By harnessing the tunable Lewis acidity and well‐defined chiral environment of the catalyst—together with the distinct mechanistic features of chiral Lewis acid catalysis—this strategy overcomes the substrate scope limitations that have constrained traditional approaches. The method demonstrates broad functional group tolerance and delivers high levels of stereocontrol across seven distinct substitution patterns, including the efficient construction of chiral P═S motifs previously considered synthetically challenging. Importantly, the approach enables efficient late‐stage derivatization of nucleosides and their analogs, thereby providing a general entry point to stereodefined P(V)‐containing bioactive molecules. This work not only expands the utility of transition‐metal Lewis acid catalysis in phosphorus chemistry, but also establishes a versatile framework for applications in drug discovery and nucleic acid‐based therapeutics where precise stereochemical control is essential.

Merging One‐ and Multi‐Photon Processes in Hydrogen‐Bonded Organic Frameworks for Enhanced NIR Light‐Driven Photothermal and Photochemical Conversions

Abstract Direct application of near‐infrared (NIR) light for solar‐thermal and solar‐chemical conversions is of emergent interest to improving efficiency in solar‐energy utilization. Herein, we report a synthetic approach to NIR‐responsive materials by self‐assembly of hydrogen‐bonded organic frameworks ( HOF‐1/2/3 ) from multifunctionalized Ru‐components incorporating chiral, photoactive, H‐bonding, π‐stacking, and protonation/deprotonation subunits. Significantly, protonation of the imidazole‐subunits in HOF‐3 promotes densified packing to extend NIR absorption tail up to 1100 nm with a narrowed bandgap of 1.41 eV, meanwhile leads to spontaneous resolution of enantiomeric Δ‐/Λ‐HOF‐3 . Consequently, remarkably enhanced photothermal effect and photocatalytic performance, including chiroptical activity induced by circularly polarized NIR light, are achieved through synergy of direct one‐ and multi‐photon NIR absorption, underscoring effectiveness to bring multifunctionalities into ordered HOFs for generation of robust and effective materials with multimode NIR responsiveness.

Tunable Oxygen Vacancy Clusters Enhanced Catalytic Activity of CeO ₂ Nanorods on CO ₂ Cycloaddition

Abstract Constructing heterogeneous halogen‐free catalysts featuring efficiently activated CO 2 and epoxides for the synthesis of cyclic carbonates via an atom‐economical route is significant but remains a big challenge. In this work, we develop an atmosphere‐assisted strategy for preparing mesoporous CeO 2 nanorods with tunable oxygen vacancy cluster concentrations, which boosts the performance of CO 2 cycloaddition. Pair distribution function (PDF) analysis elucidates that oxygen vacancy clusters regulate the dynamic equilibrium of the multiscale structure of CeO 2 via a synergistic “compression‐expansion” mechanism. Furthermore, the high concentrations of oxygen vacancy clusters form abundant frustrated Lewis pairs (FLP) sites, which remarkably promote the adsorption and activation of CO 2 with epoxides. Thus, the performance of CO 2 cycloaddition was substantially intensified. A 95% yield of cyclic carbonate was obtained when the reaction was conducted with RNR‐CeO 2 ‐H 2 at 110 °C. Moreover, the kinetic properties and the catalytic mechanism of CO 2 cycloaddition on FLP sites in RNR‐CeO 2 ‐H 2 were investigated based on the in situ DRIFTS and DFT calculations. Thus, this work provides new insights into the design of high‐performance catalysts with tunable FLP sites for the efficient activation and conversion of CO 2 into value‐added chemicals by modulating oxygen vacancy cluster concentrations.

Encapsulating Ionophores in Zeolite Imidazolate Framework‐8 for Long‐Term Monitoring of Ion Fluctuations in Living Rat Brain

Abstract Various ions in the brain (e.g., H + , K + , and Ca 2+ ) play essential roles in neural information transmission and physiopathological processes. Real‐time monitoring of these ions will provide critical information for understanding neural functions and diagnosing diseases. However, long‐term monitoring the dynamics of ions with microelectrodes remains a challenge due to the limited availability of sensing strategies capable of in vivo measurements with high stability in the mechanically soft and chemically complex brain of freely moving rats. Here, we develop a flexible and stable ion‐selective microsensor for long‐term monitoring of ions in rat brain, in which zeolite imidazolate framework‐8 (ZIF‐8) nanoparticles incorporated with ionophores are used for selective ion recognition and flexible polyvinyl alcohol (PVA) fibers sputtered with gold nanoparticles (AuNP) is used as the soft electrode substrate. The flexible microsensors allow long‐term in vivo ion sensing with good stability in the brain of behaving rat, avoiding progressively deteriorating response of traditional polymer‐based rigid ion selective microsensor caused by its instability interface and mechanical mismatch to soft brain tissue.

Surface Engineering of Hollow Microreactors with Catalytic Nanobrushes for Orthogonal Tandem Catalysis

Abstract Micro/nanoreactors with hollow structures have traditionally focused on the design of the internal catalytic microenvironment, while precise engineering of their external surfaces at a nanoscale level is particularly rare. Here, we develop a unique approach to elaborately engineer the surface of zeolitic imidazolate frameworks (ZIF‐8)‐based hollow microreactor with fluff‐like nanostructures that serve as an external catalytic platform. This involves the anchoring of high‐density micellar brushes onto the epidermis of ZIF‐8 via surface‐initiated living crystallization‐driven self‐assembly, followed by the rapid capture of multiple species to fabricate the catalytic nanobrushes. Such a nanoscale fluff‐like surface in combination with an internal cavity that encapsulates other functional components enables specific spatial isolation of various catalysts. The resultant microreactor with external PW 12 nanobrushes for esterification and internal Pt─Ni alloys for hydrogenation reveals prominent activity toward a tandem conversion of p ‐nitrobenzoic acid into benzocaine with a high selectivity of 95.4%. Remarkably, the microreactor decorated with PW 12 nanobrushes can greatly prompt the catalytic efficiency of esterification with the inhibited competition from the hydrogenation reaction. Overall, this work provides an innovative guidance for the rational creation of multifunctional microreactors with fine surface nanostructures.

Enantioselective Nickel‐Catalyzed Hydrogenation of α‐Alkylidene Succinimides Enabled by Weak Noncovalent Interactions

Abstract The development of asymmetric hydrogenation catalysts based on Earth‐abundant metals presents a sustainable alternative to efficient but resource‐limited rare‐metal systems. However, these catalysts often suffer from low catalytic activity. In this study, through a combination of density functional theory (DFT) calculations and kinetic experiments, we uncovered a positive correlation between catalyst‐substrate weak noncovalent interactions and catalytic efficiency in the enantioselective nickel‐catalyzed hydrogenation of α‐alkylidene succinimides with different N ‐protecting groups. The tert ‐butyl ( t Bu) substituent emerged as the optimal choice, significantly enhancing reactivity. This approach enabled the hydrogenation of a wide range of substrates with excellent yields (up to 99%) and enantioselectivities (up to 99% ee), achieving a substrate/catalyst (S/C) ratio of 4000—twice the efficiency of rare‐metal catalysts (S/C ≤ 2000) for similar transformations. Energy decomposition analysis (EDA) of the enantiomers revealed that the high stereoselectivity is promoted by stabilizing weak noncovalent interactions in the R ‐configured transition state.

Sequential Reconstruction of Calicheamicin γ ₁ ^I Iodo‐Thiobenzoate by Selective Carrier Protein Trapping Reveals a Flavin‐Dependent Iodinase

Abstract Flavin‐dependent halogenases (FDHs) play important roles in natural product biosynthesis, particularly chlorinases and brominases. Apart from ubiquitous mammalian iodination in thyroxine biosynthesis, iodinated natural products are extremely rare, and enzymes responsible for iodination are even less well described. A notable exception is calicheamicin γ 1 I , a potent antitumor compound containing an aromatic iodide, for which a halogenase has been proposed to mediate iodine incorporation. Despite predictions regarding the enzymes involved in iodinated aryl ring biosynthesis, experimental evidence remains limited due to challenges in substrate identification and reaction monitoring. In this study, we successfully reconstituted the enzymatic activities required for iodination and all embellishments of the highly substituted benzene ring in calicheamicin γ 1 I . Using intact‐protein mass spectrometry combined with protease cleavage, we demonstrated formation of the orsellinate thioester followed by sequential C‐2 O ‐methylation, C‐5 iodination, C‐3 oxidation, and C‐3 O ‐methylation. This research characterizes the first flavin‐dependent iodinase that acts on a carrier protein‐dependent substrate, identifies the natural substrates of a cytochrome P450 oxygenase and two O ‐methyltransferases, and provides valuable insights for biocatalysis. Additionally, these findings could facilitate the engineering of other polyketide biosynthetic pathways and contribute to optimizing fermentation conditions to generate new calicheamicin derivatives.

Engineering Unspecific Peroxygenases for Enantioselective α‐Hydroxylation of β‐Ketoesters

Abstract Unspecific peroxygenases (UPOs) are promising biocatalysts for selective oxyfunctionalization. Compared to cytochrome P450 enzymes (P450s), the catalytic potential of UPOs has been less investigated, largely due to their limited natural diversity and the challenges associated with their optimization through enzyme engineering. In this study, we engineered an UPO from Aspergillus niger ( Ani UPO) to catalyze the enantioselective α‐hydroxylation of β‐ketoesters, a valuable transformation yet to be realized in biocatalysis. Through enzyme engineering, two Ani UPO variants, Ani UPO‐M3 and Ani UPO‐M6, were developed to produce a wide range of enantioenriched α‐hydroxy‐β‐ketoesters, achieving up to 97% yield, 4140 total turnover number (TTN), and &gt;99:1 enantiomeric ratio (er). The biocatalytic process operates under mild conditions and is scalable for preparative applications. This study broadens the catalytic repertoire of UPOs and enhances their potential for industrial applications.

Highly Efficient Circularly Polarized Phosphorescence from Isolated Molecules Through Intermolecular Interactions

Abstract Organic room‐temperature phosphorescence with circularly polarization feature attracts considerable attentions owing to its unique exciton and photon properties. However, achieving high‐efficiency circularly polarized phosphorescence (CPP) under ambient conditions remains a major challenge. Herein, we report a series of CPP films by doping heterocyclic molecules with a chiral propionic acid group into polyvinyl alcohol (PVA) matrix, achieving a maximum phosphorescence efficiency of 68.4% under ambient conditions. The intermolecular interactions between the chiral isolated molecules and PVA simultaneously induce circularly polarized luminescence and enhance phosphorescence efficiency, thereby improving CPP performance. Moreover, the CPP lifetimes of the films can be rationally tuned from 1 to 944 ms by subtle modification of heteroatoms on the heterocyclic chromophores. This study provides a promising approach to developing efficient CPP materials for potential applications in optoelectronics and bioelectronics.

Three‐Dimensional Porphyrin and Phthalocyanine‐Based Covalent Organic Frameworks for Boosting Urea Oxidation

Abstract Porphyrin and phthalocyanine‐based covalent organic frameworks (COFs) have emerged as versatile scaffolds for developing high‐performance photo‐ and electrocatalysts. By enabling precise anchoring of metal species onto their cores, these COFs allow for meticulous tuning of chemical and electronic properties, facilitating single‐atom distribution and achieving outstanding catalytic performance. However, the majority of these COFs are restricted to two‐dimensional (2D) architectures, where the catalytic activity of the metal centers is often compromised due to eclipsed stacking layers, limiting their optimization potential. To address this challenge, we report the synthesis of three‐dimensional (3D) porphyrin and phthalocyanine‐based COFs with a cyt topology. This innovative structural arrangement facilitates the atomic‐level distribution of distinct metal species across steric exposed networks, and the synergistic effect of bimetallic sites leads to exceptional electrocatalytic activity in urea oxidation reactions with a current density of 10 mA cm −2 at just 1.37  V RHE . This study not only broadens the topological diversity of 3D COFs but also establishes a platform for achieving uniform and accessible multimetal distributions, paving the way for synergistic electrocatalytic materials.

Regioreversed Carbosulfenylation of Fluoroalkenes via Nickel‐Mediated Radical Sorting

Abstract Carbosulfenylation of olefins represents an important class of reactions for the synthesis of structurally diverse organosulfur compounds. Previous studies typically yield 1,2‐regioselectivity. In the context of diversity‐oriented synthesis, accessing the regioreversed products is desirable, significantly broadening the scope of these reactions. In this study, we report a nickel‐catalyzed 2,1‐carbosulfenylation of trifluoromethyl‐ and gem ‐difluoroalkenes, using free thiols and benzyl bromides as sulfur and carbon sources, respectively. The unusual regioselectivity observed is enabled by a “radical sorting” mechanism. The Ni catalyst activates benzyl bromide to generate a benzylic radical that undergoes hydrogen atom transfer (HAT) with the thiol to form a sulfur‐centered radical. The sulfur radical subsequently adds to the fluoroalkenes, resulting in an α‐fluoroalkyl C‐radical. This radical undergoes S H 2 with a Ni–CH 2 Ar to form a C(sp 3 )─C(sp 3 ) bond and quaternary center, ultimately producing valuable fluoroalkyl thioethers. Isotopic labeling experiments corroborate a hydrogen atom transfer (HAT) event within the working mechanism.

Self‐Healable Poly(ionic liquid) Copolymers Driven by Polar and Dipolar Forces

Abstract Commodity aliphatic and aromatic acrylic‐based copolymers self‐heal due to ubiquitous key‐and‐lock , ring‐and‐lock , and fluorophilic‐σ‐lock van der Waals (vdW) interactions. However, the role of these interactions in the presence of covalently copolymerized ionic liquid (IL) is not known. This study is driven by the hypothesis that covalently incorporated cation–anion pairs to form poly(ionic liquid) copolymers (PILCs) can perturb inter‐ or intra‐chain vdW interactions reflected in mechanical and electrical responses. To test this hypothesis, we synthesized a series of PILCs comprising of pentafluorostyrene (PFS) and imidazolium‐based IL monomers with variable‐length aliphatic tails (methyl and butyl). Using a combination of 2D 1 H‐ 1 H and 19 F ‐ 19 F NOESY NMR and FTIR measurements supplemented by molecular dynamic (MD) simulations, these studies demonstrate that preferentially alternating/random PILCs topologies facilitate self‐healing. The introduction of cation–anion moieties modifies the fluorophilic‐σ‐lock interactions and, along with longer aliphatic tails ─(CH 2 ) 3 CH 3 covalently attached to the imidazolium cation, enhances cation‐anion mobility, thus faster recovery from mechanical damage occurs. These findings underline how precise control over dipolar and ionic interactions through copolymer composition enables self‐healing in PILCs. These insights may open pathways for designing sustainable, mechanically resilient materials for applications in energy storage and energy harvesting.

Synthesis of a Linear Tetraboron Cation via Deprotonation of a Nonsupported Dimeric Hydroborylborenium Ion

Abstract The nonsupported B–H–B moiety of a dimeric hydroborylborenium ion can be readily deprotonated by 4‐(dimethylamino)pyridine, affording a H‐bridged linear tetraboron cation. The resulting tetraboron cation shows diverse reactivity with small molecules. Treatment of this tetraboron cation with H 2 leads to the first example of complete hydrogenolysis of main‐group homocatenated chains. On the other hand, in the presence of t BuNC, only the internal B–B bond of the tetraboron cation is cleaved, resulting in the formation of an azadiborabutadiene cation. Additionally, during the preparation of the hydroborylborenium, an unprecedented formal boryl cage‐walking was observed. Experimental and theoretical studies suggest this process involves consecutive activation of carboranyl B(9)–H bonds.