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Electron Acceptors Based on Resonant N─B←N Unit with Improved Exciton Dissociation for High‐Performance Short‐Wavelength Infrared Organic Photodetectors
AbstractDevice performance of photodiode‐type short‐wavelength infrared (SWIR) organic photodetectors (OPDs) is largely limited by poor exciton dissociation. In this work, we reported that downshifted highest occupied molecular orbital energy level (EHOMO) and increased electrostatic potential (ESP) of electron acceptor lead to improved exciton dissociation and consequently enhanced SWIR OPD device performance. Tetramers of thiophene‐fused 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (TF‐BODIPY) unit represent a new kind of electron acceptors with SWIR photoresponse. By endcapping the TF‐BODIPY tetramer with electron‐deficient pentafluorophenyl groups, we downshift the EHOMO of the electron acceptor by 0.06 eV and increase the ESP of the electron acceptor by 89 meV. As a result, the OPD devices of the electron acceptor exhibit SWIR photoresponse in the wavelength range of 0.3–1.3 µm with a maximum specific detectivity (D*) of 1.04 × 1012 Jones and a responsivity (R) of 0.16 A W−1 at 1.12 µm. This performance is among the highest reported for SWIR OPDs.
Concise Total Syntheses of Leuconoxine‐Type Alkaloids Enabled by Palladium/Norbornene‐Catalyzed Pyrrole Difunctionalization
AbstractConcise total syntheses of five leuconoxine‐type alkaloids, i.e., chloromelodinine, leuconodine A, leuconodine F, melodinine E, and leuconoxine, are achieved through a pyrrole‐centered strategy. The approach features a newly developed palladium/norbornene‐catalyzed pyrrole double C─H functionalization reaction to generate the core skeleton and a divergent oxidative dearomatization to complete the end game. In addition, no protecting group was employed, and the strategic use of a chloro substituent offers a number of advantages in these syntheses, which could have implications beyond this work. The discovery of an unusual chloro 1,2‐migration reaction enabled the first total synthesis of chloromelodinine E. This work represents the shortest syntheses of these natural products to date with 10–11 total steps.
Blocking the <i>Operando</i> Formation of Single‐Atom Spectators by Interfacial Engineering
AbstractAside from activity and selectivity, catalyst stability is a key focus in heterogeneous catalysis research. Although sintering of metal species has been considered the primary cause for deactivation of metal catalysts, our study reveals that the loss of activity at low reaction temperatures in the CeO2‐supported Pt (Pt/CeO2) catalyst in complete propane oxidation is due to the dispersion of Pt ensemble sites (nanoclusters) and their subsequent operando conversion into Pt single atoms under reaction conditions. These Pt single‐atom species exhibit low reactivity and act as spectators in the low‐temperature reaction region. To address this issue, we engineered the surface of CeO2 by introducing NbOx, which does not directly interact with Pt. Instead, NbOx blocks the strong binding sites for Pt on CeO2, thereby preventing Pt redispersion/fragmentation and preserving reactive Pt ensembles. This strategy led to a remarkable 37‐fold increase in the reaction rate compared to the Pt/CeO2 catalyst. Our findings emphasize the importance of suppressing the formation of noble metal single‐atom spectators through innovative surface engineering strategy. These mechanistic insights not only advance the understanding of the materials science of Pt/CeO2 but also extend to critical technological fields such as energy conversion systems and environmental remediation technologies.
Interfacial Lithium Cations Catalyze Biomimetic Aerobic Oxygenation via Short‐Range Electrostatic Interaction
AbstractEnzymes often involve short‐range electrostatic interactions in the deliberate microenvironment for accelerating the catalysis. Comparatively, electrostatic interactions from ions in solutions are mostly shielded by solvent or counter‐ion shells, creating negligible catalytic effects. Herein, we discovered that the interfacial Li+ cations accumulated on electrodes catalyze the selective water‐involved O2 electro‐reduction into peroxide anion (OOH−), forming an active side‐on Li+–OOH− complex via short‐range electrostatic interaction. This complex reduces the O2 reduction energy barrier and increases the nucleophilicity, expediting the aerobic oxygenation of ketones. Aside from trapping active intermediates, Li+ cations also attract the excessive water dipoles to prevent them from quenching the active Li+–OOH− complex. By using probe‐assisted quantitative methods, we demonstrated the unique under‐coordinative characteristics of interfacial Li+ for interacting with reaction intermediates, and the effective concentration of under‐coordinative Li+ on the interface is an order of magnitude higher than in the bulk solution. These analyses provide essential evidences about the intrinsic difference between bulk ions and interfacial ions toward catalysis.
Synergistic Effects of Interfacial Chemistry and Ion‐Solvent Interactions to Enable Reversible Magnesium Metal Anode in Chloride‐Free Mg(TFSI)<sub>2</sub> Electrolytes
AbstractPassivation of magnesium (Mg) anode in the chloride‐free magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2) electrolyte is a key challenge for Mg metal batteries. Tailoring solvation structure and solid electrolyte interphase (SEI) has been considered an effective strategy. Herein, a series of imidazole co‐solvents with different branched‐chain structures (methyl, ethyl, and propyl) are introduced into the Mg(TFSI)2‐ether electrolyte to address the passivation issue. The ion‐solvent interaction, interfacial adsorption effect, and SEI formation are comprehensively studied by theoretical calculations and experimental characterizations. Through molecular structure analysis, the long‐chain 1‐propylimidazole (PrIm) exhibits a strong coordination ability to Mg2+ and a favorable parallel adsorption configuration on the Mg surface. As a result, PrIm co‐solvent can not only restructure the solvation sheath of Mg2+, but also act as a dynamic protective shield to repel a part of TFSI− and 1,2‐dimethoxyethane (DME) away from the Mg surface. Benefiting from the synergistic regulation effect of interfacial chemistry and ion‐solvent interactions, the chloride‐free Mg(TFSI)2‐DME + PrIm electrolyte ensures minimal interface passivation and achieves highly reversible Mg plating/stripping. This work provides a guiding strategy for solvation structure regulation and interface engineering for rechargeable Mg metal batteries.
Organic–Inorganic Hybrid Rare Earth Halide Glasses for Tunable Multicolor X‐ray Scintillation
AbstractRare earth–based all‐inorganic glass‐ceramics have played an important role in the field of optoelectronics. However, the research of organo–inorganic hybrid rare earth halide glass that can be produced at low temperatures is still in the blank stage. In this paper, we report for the first time novel amorphous organic–inorganic hybrid rare earth–based halide luminescent glasses, Bzmim3LnCl6 (Bzmim = 1‐benzyl‐3‐methylimidazolium; Ln3+ = Tb3+, Eu3+), and realize tunable multicolor photoluminescence emission. By adjusting the ratio of Tb3+/Eu3+ within the Bzmim3LnCl6 glass, we have successfully induced controllable radioluminescence properties ranging from green to red under X‐ray irradiation. Notably, these amorphous organic–inorganic hybrid rare earth glasses exhibit remarkable sensitivity to variations in X‐ray dose, suggesting promising applications in the field of passive color visualization radiation detection. Furthermore, the Bzmim3TbCl6 glass demonstrates exceptional light transmittance greater than 85% across the 480–800 nm range, which results in superior spatial resolution in X‐ray imaging (>25 lp mm−1). These findings not only provide a good example for the design and development of hybrid rare earth–based halide glasses but also hold great potential for applications in detection, sensing, illumination, and display technologies.
Iridium‐Catalyzed Asymmetric Allenylic Substitution via Kinetic Resolution Enabled by New Monodentate Ligands
AbstractIridium‐catalyzed asymmetric allenylic substitution represents a useful method for the construction of allenes bearing an allenylic central chirality, but current success has uniformly relied on only one specific chiral bidentate ligand. Herein, we address the limitation by the design of a new type of monodentate ligands leading to not only excellent enantiocontrol in allenylic substitution but also efficient kinetic resolution of α‐allenylic alcohols, a new phenomenon never observed before in iridium‐catalyzed allenylic substitution. This is also a rare demonstration of the non‐enzymatic kinetic resolution of α‐allenylic alcohols. A range of highly enantioenriched allenylic diarylmethanes and α‐allenylic alcohols could be accessed under mild conditions. Control experiments and DFT studies indicated that this process proceeds by an SN1 pathway featuring a rate‐determining ionization step followed by ligand‐controlled enantiodetermining nucleophilic addition. The newly designed rigid and bulky ligands modified from SPHENOL were believed to assemble the key iridium‐bound allenylic carbocation intermediate in a different complexation mode, thus serving as the origin of enantiocontrol and the unprecedented kinetic resolution.
Fast and Autonomous Mannosylated Nanomotors for Dynamic Cancer Cell Targeting
AbstractAn attractive strategy in cancer cell therapy is to employ motile nanoparticles that can actively search for their target. Herein, we introduce mannosylated compartmentalized cross‐linked enzyme‐driven nanomotors (c‐CLEnM), which exhibit specific and efficient targeting of Hep G2 cells through elevated autonomous motion. In this design, we constructed biodegradable bowl‐shaped stomatocytes encapsulating the enzymes glucose oxidase (GOx) and catalase (CAT) within their nanocavity. A subsequent enzyme crosslinking reaction was performed to guarantee their stability. Furthermore, the c‐CLEnM were surface modified with a mannose‐functional glycopolymer, enabling binding with receptors expressed on Hep G2 cells. Interestingly, the targeting ligands on the nanomotors not only improved their specificity toward cancer cells but also enhanced motility. Compared to the non‐mannosylated nanomotors, mannosylated c‐CLEnM exhibited enhanced motion and higher targeting efficiency to cells in glucose‐containing ionic environments. The unexpected acceleration in speed resulted from the surface modification of these nanomotors with a glycopolymer layer, which increased the zeta potential and created a shielding effect that mitigated the influence of the surrounding ions. This nanomotor design highlights the synergistic effect of functional glycopolymer modification on cellular uptake, adding an additional level of control to nanomotors for application in cancer therapy.
Fullerene‐Buffered Electron Shuttle of Ru/RuO<sub>2</sub> with Switchable Active Sites Enables Robust and Efficient Bifunctional Alkaline Water Electrolysis
AbstractDeveloping highly‐efficient and robust bifunctional electrocatalyst for overall water splitting (OWS) is desirable, but it confronts long‐term challenge in the local structural reconstruction of catalyst during the hydrogen and oxygen evolution reaction (HER and OER). As inspired by the stable acid–base buffer system in human life, here we construct an electron buffer system to well address the key issue of structural reconstruction, in which the charge‐buffered fullerene renders Ru‐based active species to be reversibly shuttled between Ru and RuO2 during HER and OER. Consequently, the as‐prepared Ru‐RuO2/C60‐x catalyst exhibits overpotentials of merely 7 and 194 mV at 10 mA cm−2 for HER and OER in alkaline conditions, respectively. The photovoltaic‐driven OWS device with a solar‐to‐hydrogen (STH) efficiency of 18.9% and an anion exchange membrane water electrolysis (AEMWE) system with good robustness was fabricated based on Ru‐RuO2/C60‐x. It was unraveled by in situ/operando spectroscopy and theoretical calculation that the significantly promoted performance of water electrolysis benefits from the fullerene‐based electron shuttle effect on inhibition of structural reconstruction and electronic structural modulation of active sites as well as adsorption energy of the reaction intermediates. Our work may open an avenue to develop efficient and robust bifunctional electrocatalyst for promising industrial water electrolysis.
Oxygen‐Substituted Porous C<sub>2</sub>N Frameworks as Efficient Electrocatalysts for Carbon Dioxide Electroreduction
AbstractThe electrochemical carbon dioxide reduction reaction (CO2RR) provides a green avenue for decarbonizing the conventional chemical industries. Here, a structure–selectivity relationship of catalysts is pivotal for the control of a highly selective and active CO2RR pathway. We report the fabrication of an oxygen‐substituted C2N as metal‐free catalyst (O─C2N) for electrochemical CO2─to─CO conversion with tunable O microenvironment. Combined spectroscopic analysis reveals a fine tailored N─C─O moiety in O─C2N, where C─O─C species (e.g., ring in‐plane ether) become the dominant oxygen configurations at higher pyrolysis temperatures. Based on experimental observations, a correlation between the exocyclic O‐substituted N─C─O─C moieties and CO selectivity is established, giving clear chemical tools for active structure design. The optimized O─C2N electrocatalysts with the dominant appearance of C─O─C moieties exhibit an outstanding 2e− CO2RR performance with a CO selectivity up to 94.8%, which can be well maintained in a practical flow‐cell reactor with an adjustable syngas feature.
Halogen‐Atom Transfer Enabled <i>Z</i>‐Selective Styrene Synthesis via Dual Cobalt and Photocatalysis Through Coupling of Unactivated Alkyl Iodides With Terminal Arylalkynes
AbstractAn efficient Z‐selective cobalt‐catalyzed reductive hydroalkylation of terminal aryl alkynes with unactivated alkyl iodides has been achieved, providing a straightforward and modular route to access 1,2‐disubstituted Z‐styrenes. This reaction operates under mild conditions without requiring over‐stoichiometric amounts of metal terminal reductants. Excellent Z/E ratios and good to excellent yields can be achieved for diverse and complex scaffolds with remarkable functional‐group compatibility. One potential utility of this reaction is demonstrated by the efficient synthesis of several syn homoallylic alcohols in a one‐pot two‐step sequence. Control experiments strongly support that the halogen‐atom transfer (XAT) process is the key to generating carbon radicals. DFT studies suggest that the catalytic system involves the Co(II)/Co(III) cycle and the steric repulsion between the Co(II) catalyst, and the alkenyl radical in radical capture by Co(II) is the dominant factor controlling the Z/E selectivity. This approach represents the first example of merging photo‐XAT with cobalt‐catalyzed reductive coupling of terminal aryl alkynes with unactivated alkyl iodides.
Cold‐Optimized Zinc‐Ion Batteries: Enhanced Stability at −5 °C
AbstractAqueous zinc‐ion batteries (AZIBs) have been extensively studied under room and ultralow temperature conditions. However, mechanism studies at intermediate temperature ranges remain limited. In this work, we investigate the electrochemical performance of an AZIB using a commonly employed 3 M ZnSO4 electrolyte across the intermediate temperature range of 25 to −15 °C. Notably, we find that the battery with a double hydroxide cathode exhibits optimized performance at −5 °C, demonstrating significantly enhanced cycling stability compared to 25 °C. Mechanistic studies reveal that unfavorable H+‐associated reactions at both the cathode and anode are effectively alleviated at −5 °C, contributing to improved cycling stability. Spectroscopic and theoretical analyzes show that changes in the electrolyte environment at −5 °C—such as reduced electrochemical activity of H2O, increased H‐bond strength, and decreased total number of H bonds—impede H+ diffusion through H‐bond network via the Grotthuss mechanism. These effects collectively suppress harmful H+‐associated reactions, allowing Zn2+ insertion/deinsertion to dominate the charge storage process. This work provides valuable insights into the enhanced performance of AZIBs at sublow temperatures and presents opportunities for extending battery operation in near‐freezing environments.
Geminiarene‐Based Charge‐Transfer Cocrystals with Dichromatic Variants and Stimuli‐Responsive Structural Interconversion
AbstractThe construction of stimuli‐responsive charge‐transfer (CT) cocrystals is a challenging frontier in organic crystal engineering. Here, we introduce a gemini CT cocrystal system with dichromatic stimuli‐responsiveness by utilizing the unique dual/gemini conformational feature of geminiarene. Geminiarene binds with the electron‐deficient guest 1,2,4,5‐tetracyanobenzene through exo‐wall interactions to form two types of gemini CT cocrystals with distinct colors. Single‐crystal structures, along with theoretical calculations and spectral analyses, reveal that the color differences are primarily due to the dual molecular conformations of geminiarene and their distinct electronic properties. Notably, the gemini CT cocrystal system can be used to develop a novel dichromatic sensing material capable of distinguishing commonly used organic solvents. Moreover, the stimuli‐responsive interconversion between the two conformations of geminiarene enables a loop‐locked structural transition in the cocrystal system. This work expands CT cocrystal engineering and offers a new strategy for designing intelligent responsive materials for sensing and adsorption applications.
Antifreeze Protein Mimics Realizing Stable Low‐Temperature‐Resistant Aqueous Zn‐Ion Batteries with High Water Content
AbstractRechargeable aqueous metal batteries offer inherent safety and low cost due to the predominance of water in their aqueous electrolytes, yet their practical applications are severely limited by electrolyte freezing under subzero conditions. Drawing inspiration from the mechanism of antifreeze proteins (AFPs) that protect living organisms from freezing damage, we synthesize oxidized quasi‐carbon nitride quantum dots (OQCNs) featuring a regularly in‐plane structure commensurate with the prism face of hexagonal ice crystal. At an ultralow concentration, the as‐synthetic OQCNs effectively mimic AFP functionalities by controlling ice crystal morphology, suppressing ice growth kinetics, and inhibiting ice recrystallization. This synergistic mechanism preserves continuous ion transport pathways while mitigating physical damage to battery components caused by ice crystal growth. Molecular dynamics simulations demonstrate that the Gibbs–Thomson effect underpins the suppression of ice growth, avoiding complete solidification of the electrolyte under subzero conditions. The OQCNs‐modified electrolyte exhibits exceptional cryogenic performance at −30 °C, with Zn||Zn symmetric cell maintaining stable cycling of 1000 h and Zn||NH4+‐intercalated vanadium oxide (NVO) battery preserving 91.48% capacity retention through 5000 cycles (over 90 days). This work unveils a bioinspired paradigm that significantly enhances the performance of eco‐friendly, high‐moisture electrolytes, paving the way for robust, low‐temperature‐resistant zinc‐ion batteries and related aqueous electrolyte‐based technologies.
Nonclassical Hydrogen Bond‐Based Efficient Solid‐State Organic Emitters Enabled by a Synergistic Anion and Mechanical Bond Effect
AbstractTraditional fluorophores often face aggregation‐caused quenching (ACQ), limiting their efficacy in high‐concentration applications. We demonstrate that a combined effect of anion and mechanical bond can significantly increase fluorescence intensity, up to 14‐fold, and a quantum yield of 97.0%. A large number of crystal analyses reveal that this enhancement is primarily driven by nonclassical hydrogen bonds, which stabilize the structure and restrict molecular motion. The versatility of this synergistic effect opens up new avenues for applications, including circularly polarized luminescence (CPL) facilitated by chiral anions and the development of a fluorescence switchable rotaxane shuttle‐based stimuli‐responsive material.
Total Synthesis of Euphane Triterpenoids Using Metal‐Catalyzed Hydrogen Atom Transfer
AbstractEuphane triterpenoids are widely distributed in nature and show various intriguing bioactivities, but relatively few synthetic routes to them have been described. Here, we report asymmetric convergent total syntheses of euphanes involving two triterpenoids and two nortriterpenoids: euphol, 25,26,27‐trisnor‐3β‐hydroxy‐euphan‐24‐al, euphorbiumrin D, and 3‐oxo‐tirucall‐7‐ene‐3,20‐dione. The syntheses employ an enantioselective Antilla allylboration and intramolecular radical cyclization to construct ring A, a palladium‐catalyzed Liebeskind stannane‐thioester coupling to connect ring A with the bicyclic CD system, and a novel radical cascade with metal‐catalyzed hydrogen atom transfer (MHAT) to complete the polycyclic architecture. The late‐stage syntheses of both triterpenoids feature a diimide reduction and a MHAT/1,5‐hydrogen transfer cascade to diastereoselectively forge the C20 and C17 stereogenic centers.
Isolable Three‐Coordinate Base‐Stabilized Alumylene: A Precursor of Persistent Acceptor‐Free Monomeric Aluminum Oxide
AbstractAn isolable monomeric alumylene 2 stabilized by two donating ligands (phosphine and NHC) has been synthesized. Experimental and theoretical analysis confirm that the NHC ligand in 2 is labile and reversibly dissociates from the AlI center above −20 °C. Of particular interest, despite being thermodynamically stabilized by two donor ligands, alumylene complex 2 exhibits a high reactivity with a considerably higher nucleophilicity compared to the monophosphine‐ligated complex 5. It is interesting to note that 2 reacts immediately with N2O at −90 °C, allowing the synthesis of bis‐ligated aluminum oxide 15, which is stable up to −70 °C.
Oxygen Atom Migration Dominates Anomalous Reversible Oxidation of Ru Nanosheets
AbstractOxidation is a ubiquitous reaction in nature. For most metals (especially metal nanoparticles [NPs]), they will be completely oxidized under suitable conditions, except ruthenium (Ru). In this work, in situ transmission electron microscopy (in situ TEM) and ex situ spectroscopy were employed to investigate the oxidation process of Ru nanosheets. Ex situ spectroscopic analysis demonstrates the incomplete oxidation of Ru nanosheets to RuO₂, while the in situ TEM observations uncover an anomalous reverse phase transformation from the oxidized to metallic phase during oxidation. Combined with theoretical calculations, the oxygen atom migration dominates the reversible oxidation process, strikingly distinct from the unidirectional oxidation pathways in conventional metallic systems. The as‐generated abundant Ru─RuO2 heterointerfaces formed through reversible oxidation provide a wealth of active sites for electrochemical alkaline hydrogen evolution reaction (HER). Herein, the study not only lays a foundation for the understanding complex dynamic oxidation processes, but also offers new insights into the design of nanocatalysts.
Aqueous Self‐Assembly of Cylindrical and Tapered Bottlebrush Block Copolymers
Abstract The self‐assembly of amphiphilic bottlebrush block copolymers (BCPs), featuring backbones densely grafted with two types of side chains, is less well understood compared to linear BCPs. In particular, the solution self‐assembly of tapered bottlebrush BCPs—cone‐shaped BCPs with hydrophilic or hydrophobic tips—remains unexplored. This study investigates eight tapered and four cylindrical bottlebrush BCPs with varied ratios of hydrophobic polystyrene (PS) and hydrophilic poly(acrylic acid) (PAA) side chains, synthesized via sequential addition of macromonomers using ring‐opening metathesis polymerization (SAM‐ROMP). Self‐assembled nanostructures formed in water were analyzed using cryogenic transmission electron microscopy, small‐angle neutron scattering, and dynamic light scattering. Most BCPs generated multiple nanostructures with surface protrusions, including spherical micelles, cylindrical micelles, and vesicles, alongside transitional forms like ellipsoids and semi‐vesicles. Coarse‐grained molecular dynamics simulations supported the experimental findings, which revealed two distinct self‐assembly pathways. The first involved micelle fusion, producing elliptical and cylindrical aggregates, sometimes forming Y‐junctions. The second pathway featured micelle maturation into semivesicles, which developed into vesicles or large compound vesicles. This work provides the first experimental evidence of vesicle formation via semivesicles in bottlebrush BCPs and demonstrates the significant influence of cone directionality on self‐assembly behavior in these cone‐shaped polymeric amphiphiles.
Preparation of Thermally and Photochemically Immobilized N‐type Conjugated Polymer Films via Quantitative Backbone Editing
AbstractWe report a series of n‐type conjugated polymers based on PNDI‐TfBTT and PNDIV‐TfBTT backbones constructed from electron‐deficient naphthalene diimide (NDI) and fluorinated benzothiadiazole (fBT) units, with PNDIV‐TfBTT incorporating a vinylene spacer. Quantitative postpolymerization modification (PPM) via nucleophilic substitution replaced the fBT fluorine with thioether side chains, optionally containing azide groups. Thioether substitution improved solubility, while subtly changing the ordering of polymer films. Azide incorporation enabled both thermal and photochemical crosslinking, yielding insoluble and immobile films that retained good electron transport; although UV crosslinking initially reduced mobility, subsequent thermal annealing largely restored crystallinity and performance. This work underscores the utility of precise backbone editing to fine‐tune the electronic and morphological properties of n‐type polymers, offering new avenues for the fabrication of stable, patterned active layers in advanced organic electronic devices.