Browse Articles

Valency‐Controlled Multiphotochromism: Gated Switching and Photoswitchable Lewis Superacidity at Silicon

ABSTRACT Multiphotochromic systems promise multistate molecular information storage, yet strategies to control their switching‐state distributions and interchromophore communication remain scarce. Here, we demonstrate that silicon valency can serve as a molecular control element to gate multiphotochromism. Two silicon‐based diarylethene Lewis acids undergo stepwise twofold cyclization, with interconversion between tetra‐ and pentacoordinate states modulating electronic coupling between ligands. Donor coordination enables selective monocyclization, wavelength‐gated activation, or complete suppression of photoreactivity, depending on the bound base. In the donor‐free state, stepwise cyclization progressively enhances Lewis acidity and culminates in the first example of photoswitchable Lewis superacidity. In addition, dynamic Si─N/Si─O bond metathesis provides thermodynamic access to switching‐state distributions beyond statistical photochemical limits. These findings establish valency control as a design principle for multiphotochromic architectures.

Brain architecture of punishment learning

Learning from punishment allows animals to suppress actions that produce adverse consequences while maintaining other rewarded behaviors. However, the brain mechanisms of this learning are poorly understood. Here, we combined instrumental behavioural analysis, whole-brain Fos mapping, spatial transcriptomics, computational network analysis, and chemogenetic inhibition in male and female mice. A within-subjects yoking procedure showed that suppression depended on the instrumental response–punisher contingency rather than matched shock exposure or embedded Pavlovian stimulus–shock relations. Whole-brain Fos network analysis showed marked reorganization of brain-wide Fos correlation structure after punishment learning. Punishment preserved modular, small-world organization characteristic of brain networks while reallocating regional community membership and increasing the centrality of the basolateral amygdala, zona incerta, and midbrain tegmentum. Spatial transcriptomics within these regions identified punishment-associated transcriptional programs in basolateral amygdala glutamatergic neurons, zona incerta GABAergic neurons, and multiple ventral midbrain GABAergic and dopaminergic populations. In silico deletion predicted that the basolateral amygdala, zona incerta, and rostral linear nucleus jointly support punishment learning. Consistent with this, multisite chemogenetic inhibition of these regions impaired punishment learning. Single-region inhibition revealed dissociable contributions of basolateral amygdala and zona incerta to within-session and between-session retention of punishment learning. Together, these findings show that punishment learning is supported by a brain network that enables animals to selectively suppress actions that produce adverse consequences. Significance statement Punishment learning is essential for adaptive behaviour because it allows animals to stop actions that produce harm while maintaining other rewarded actions. We show that this form of learning is not explained by shock exposure, Pavlovian fear, or activation of a single brain region. Instead, punishment learning reorganises brain-wide activity networks, recruits spatially structured transcriptional programs in specific neuronal populations, and depends on the function of the basolateral amygdala, zona incerta, and rostral linear nucleus of the raphe. These findings provide a multiscale account of how the brain learns from adverse consequences.

Ordered Pt ₃ Mn Intermetallic Nanoparticles Supported on Atomically Dispersed Mn–N–C as Electrocatalysts for Fuel Cells

ABSTRACT Compared with conventional solid‐solution alloy nanoparticles with disordered atomic structures, platinum (Pt)‐based intermetallic compounds (IMCs) are recognized as highly promising electrocatalysts for practical fuel cell applications, on account of their long‐range periodically ordered atomic arrangements. Nevertheless, the rational development of Pt‐based catalysts featuring both high intrinsic activity and long‐term durability remains a key challenge in this field. In this work, by simultaneously introducing manganese (Mn) with low‐electronegativity into both the active component and the support, we report an efficient electrocatalyst toward the oxygen reduction reaction (ORR), composed of L1 2 ‐ordered Pt 3 Mn nanoparticles on Mn single‐atom nitrogen‐doped carbon support (L1 2 ‐Pt 3 Mn@Mn–N–C). The incorporation of Mn, the strong anchoring effect arising from the hierarchically porous structure of the support, and the directional interfacial electron transfer between L1 2 ‐Pt 3 Mn and Mn–N–C synergistically mitigate the adsorption strength of key oxygen intermediates and suppress the dissolution of surface Pt sites. Superior catalytic performance and durability are validated in proton exchange membrane fuel cells (PEMFCs), achieving a peak power density of 1.15 W cm −2 under H 2 /air conditions. After 30 000 square‐wave cycles, the voltage loss at 0.8 A cm −2 is only 19 mV, ranking it among the top‐performing Pt‐based cathode catalysts reported to date.

Redox Chemistry Enables Excellent Capacity and Ultra Long Life Aqueous Ammonium Ion Batteries

ABSTRACT Ammonium‐ion batteries are promising for energy storage with low cost, high ionic conductivity, and excellent safety. However, their long‐term cycling stability is far from the industrial application expectation owing the lack of suitable electrode materials. Here, we report the redox chemistry enables excellent capacity and ultra long life of Prussian blue analogues as performant electrode materials by regulating their t 2g e g occupancy of M’ d‐orbitals. This work shows that the electronic configuration of M’ is crucial for redox reversibility, structural robustness, and ultimately tolerance for NH 4 + storage stability. For (NH 4 ) 2 NiFe(CN) 6 , the metallic center with fully filled t 2g orbitals ensures the stable structure, while the half‐filled e g orbitals in the high‐spin states enhance the axial transport of electrons. As a result, the key metric for the best one (NH 4 ) 2 NiFe(CN) 6 delivers a reversible capacity of ∼70 mAh g −1 , superior rate performance, and outstanding long‐life performance, sustaining stable output for over 10 000 h at 100 mA g −1 and 30 000 cycles at 1000 mA g −1 . In situ XRD and first‐principles calculations further confirm highly reversible redox processes. This study presents a novel and effective strategy for improving the performance and stability of electrode materials, offering valuable insights for the development of next‐generation energy storage systems.

Boosting Natural Rubber Performance by Backbone Rigid Functionalization

ABSTRACT Natural rubber relies on irreversible vulcanization to enhance material performance, but the resulting densely crosslinked networks resist breakdown, rendering conventional physical recycling methods ineffective. Developing backbone‐level functionalization strategies that simultaneously improve performance and enable controlled deconstruction remains a fundamental challenge. Here we develop a backbone rigid functionalization (BRF) strategy to install rigid, polar cyclobutane units directly into natural rubber via catalyst‐free [2+2] photocycloaddition. Incorporation of cyclobutane‐fused succinimide units substantially enhances tensile strength and toughness. Simply varying the reaction time enables continuous tuning of material behavior from viscoelastic polymers to elastomers and plastomers. When combined with vulcanization, the polar‐functionalized natural rubber yields high‐performance thermosets with a five‑fold improvement in stress, Young's modulus and toughness relative to conventional vulcanizates. Notably, the cyclobutane‐fused succinimide units undergo force‐triggered cycloreversion upon bulk ball‐milling, enabling vulcanized rubber with on‐demand hydrolytic degradability. This single‐step BRF process provides a practical pathway for accessing high‐performance rubbers with on‐demand degradability.

Amidase‐Catalyzed Desorption of CO ₂ Captured in Aqueous Monoethanolamine (MEA) Solutions

ABSTRACT Aqueous monoethanolamine (MEA) solutions can absorb CO 2 from industrial point sources via amine scrubbing. Mechanistically, CO 2 diffuses in and reacts with MEA or hydroxide to form a mixture of carbamate and carbonate/bicarbonate. Subsequently, CO 2 is released for storage or utilization via an energy‐intensive thermal solvent‐regeneration process. Here, we explored biocatalytic acceleration of the solvent regeneration step, which accounts for the dominant energy cost of carbon dioxide removal (CDR) processes. We conducted a sequence mining campaign based on urethane‐degrading Amidase Signature superfamily enzymes and discovered amidases that hydrolyze MEA carbamate, thereby increasing the overall release rate of CO 2 . The most promising candidate, an amidase from Parageobacillus caldoxylosilyticus (PcAmd), showed good thermostability ( T m around 70°C) and a specific activity against MEA carbamate of about 1 U/mg (20 nKat/mg). We found that PcAmd accelerated the regeneration of MEA sorbent. Specifically, PcAmd at 1 µM increased the initial CO 2 release rate by about 20%, and the time required to release 80% of the captured CO 2 was reduced by approximately half compared to enzyme‐free solutions. These results identified a novel potential of amidases in carbon capture and motivated further efforts to discover or engineer enzymes with better stability and activity for industrial CDR applications.

Modern Cyanine Dye‐Based Photosensitizers for Medical Applications

ABSTRACT The emergence of photochemical technology has revolutionized the fields of biology and medicine. Among them, photodynamic therapy represents a highly precise oncological treatment method. However, its therapeutic efficiency is severely hindered by inherent bottlenecks of traditional photosensitizers. While cyanine dyes have become the preferred molecular framework for overcoming these challenges. Over the past 8 years, our research team has made pioneering contributions in this field, which has catalyzed sustained interdisciplinary interest, spurring the rational design of a broad spectrum of photosensitizers. However, due to the fragmentation of internal communication within this field and the ambiguity of some key technologies, inconsistencies have emerged in some important application aspects. Given the significant contributions and professional expertise of our research team, we have conducted this review to provide a comprehensive introduction. We will examine the evolving biomedical applications of it through multiple perspectives, including photosensitization efficiency, hypoxic microenvironments, tissue penetration limitations, control of photosensitization activity, reactivation of the immune system, and transformation of molecular design paradigms. The aim is to provide both experts and non‐experts with a clear and understandable resource, promoting a deeper understanding of modern cyanine dye‐based photosensitizers and proposing actionable principles for the design and innovation of next‐generation cyanine photosensitizers.

Regiodivergent Hydrogermylation of Alkynes Enabled by Dinuclear Cobalt Catalysts Bearing Different Ligands

ABSTRACT Transition‐metal‐catalyzed hydrogermylation of alkynes represents an ideal atom‐economical method to prepare vinylgermanes that are valuable reagents in medicinal chemistry, material science and organic synthesis. Nevertheless, its development―particularly in achieving high regioselectivity with earth‐abundant 3d metal catalysts―remains as a formidable challenge. Herein, we report regiodivergent hydrogermylation reactions of alkynes employing structure well‐defined dicobalt carbonyl complexes as catalysts: the reaction using [(IPent)Co 2 (CO) 7 ] (IPent = 1,3‐di(2,6‐di(pentan‐3‐yl)phenyl)imidazol‐2‐ylidene) affords selectively α ‐vinylgermanes, whereas that with [(Xantphos)Co 2 (CO) 6 ] (Xantphos = (9,9‐dimethyl‐9 H ‐xanthene‐4,5‐diyl)bis(diphenylphosphane) yields selectively β‐ ( E )‐vinylgermanes. Both cobalt catalysts effect the hydrogermylation of alkyl‐ and aryl‐substituted terminal alkynes with tertiary hydrogermanes with good functional group compatibility in good to high yields and selectivity. Mechanistic studies establish alkyne‐bridged dicobalt carbonyl species as the active intermediates in both catalytic systems and the distinct steric nature of the metalloligands LCo (L = IPent, Xantphos) governs the observed regiodivergent selectivity. The application of these dicobalt‐catalysts to alkyne hydroelementation reactions allows the selective preparation of different configurational isomers of vinylgermanes/silanes that can be further utilized for the stereoselective synthesis of alkene derivatives.

Molecular N‐Type Doping Unlocks Low‐Threshold Nanosecond Lasing in a Microcavity‐Integrated OLED Toward Electrically Pumped Organic Lasers

ABSTRACT Organic semiconductors are attractive for the development of flexible, wavelength‐tunable lasers. However, most reported organic micro/nanolasers rely on femtosecond‐pulsed optical pumping, which is impractical for real‐world applications. This limitation has urged the pursuit of electrically pumped organic lasers; yet their realization remains a long‐standing challenge primarily due to a fundamental materials dilemma, in which high‐gain organic semiconductors often suffer from poor, unbalanced charge transport. Here, we demonstrate that this intrinsic trade‐off can be effectively alleviated through a molecular doping strategy. Employing a high‐gain spirofluorene derivative as the emissive layer, we introduce an n‐type doped layer to construct an organic light‐emitting diode (OLED), achieving more balanced charge transport while preserving outstanding optical gain. Consequently, singlet‐polaron annihilation is significantly suppressed, as evidenced by reduced efficiency roll‐off and electrically pumped transient absorption measurements. When integrated with a distributed feedback (DFB) resonator, the resulting device exhibits ultra‐narrow (∼2 nm) electroluminescence under pulsed current injections and delivers low‐threshold nanosecond lasing under an optical–electrical co‐pumping configuration, thereby demonstrating a practical architecture for implementing organic laser diodes. Our work provides a general strategy to overcome the intrinsic paradox where high‐gain organic semiconductors struggle to maintain balanced charge transport, illuminating a pathway toward light amplification under electrical excitation.

Precise Multi‐Site Borylation Engineering of Indolo[2,3‐c]Carbazole‐Bridged Narrowband MR‐TADF Emitters

ABSTRACT Indolocarbazole‐bridged double‐boron multi‐resonance thermally activated delayed fluorescence (MR‐TADF) materials enable precise modulation of emission colors while retaining ultra‐narrowband characteristics in organic light‐emitting diodes (OLEDs). Herein, we first introduce indolo[2,3‐c]carbazole (23cIC) into the design of MR‐TADF emitters and develop an electronically and sterically controlled multi‐site borylation strategy. This strategy affords the electronically favored exo‐configuration for Tbu‐exo, which exhibits narrowband green emission at 524 nm with a full‐width at half‐maximum (FWHM) of 20 nm, while yielding the steric hindrance‐guided endo‐configuration for Ad‐tph‐endo exhibiting by yellow emission at 566 nm with a FWHM of 25 nm. Notably, the endo‐configuration gives rise to ( P / M )‐Ad‐tph‐endo, which exhibits significant chiral luminescence properties. Vacuum‐deposited OLEDs based on Tbu‐exo and Ad‐tph‐endo exhibit emission peaks at 530 nm (FWHM = 27 nm) and 568 nm (FWHM = 33 nm), respectively, both achieving external quantum efficiencies (EQE) exceeding 30%. Furthermore, we fabricated solution‐processed top‐emitting OLEDs based on Tbu‐exo for the first time, which realize ultra‐narrow pure‐green emission with CIE coordinates of (0.21, 0.75)—closely approaching the BT.2020 green standard—and a record‐high current efficiency of 200.9 cd A −1 .

Synthesis and Activity‐Based Protein Profiling Identifies Aldo‐Keto Reductase 1C3 as Target Protein of Myxoglucamides

ABSTRACT Myxoglucamides, natural products recently isolated from Cystobacterineae sp., are featured by an unprecedented vinyl‐substituted α‐keto‐γ‐amino acid that is linked to a glycosylated 14‐methyl‐pentadecanoic acid. Thus, they unite elements from three biomolecular classes in a compact glycolipopeptide. To elucidate the biological relevance of this arrangement, we searched for molecular targets by activity‐based protein profiling (ABPP)—although a phenotypic bioactivity has not been reported. An access to the compound class was established through the first total synthesis of myxoglucamide A in 11 steps. A proteome‐wide ABPP study led to the identification of aldo‐keto reductase 1C3 (AKR1C3) as the primary target of myxoglucamides in human cells. AKR1C3 is an oncogenic factor involved in prostaglandin and steroid synthesis, promoting the growth, proliferation, and metastasis of carcinoma cells. The functional inhibition of AKR1C3 by a competitive mechanism (IC 50 = 1.61 µ m ) was validated in vitro, and 20 analogs provided structure‐activity relationships and more potent analogs (IC 50 = 181 n m ). Biophysical interactions were quantified by thermal shift assays, and essential molecular protein‐ligand interactions were characterized by X‐ray crystallography at 2.0 Å resolution. The study implies that the search for targets of natural products is rewarding even in the absence of an initial phenotypic activity.

A Review of Electrochemical–Biological Coupling Systems for CO ₂ Valorization: Catalytic Fundamentals, System Integration, and Industrial Outlook

ABSTRACT To support dual‐carbon goals and address the limitations of conventional CO 2 valorization technologies, this review summarizes recent advances in electrochemical–biological coupling systems for high‐value CO 2 utilization, with emphasis on catalytic fundamentals, system integration, and industrial prospects. We discuss catalyst and reactor design for CO 2 electroreduction to C 1 /C 2 liquid platform molecules, particularly formate, acetate, and methanol, and their subsequent biological conversion. The review further examines metabolic and engineering strategies by which microbial cell factories assimilate electro‐generated substrates to produce high‐value compounds, including amino acids, organic acids, polysaccharides, and polyhydroxybutyrate (PHB). Key bottlenecks in electrocatalyst stability, gas diffusion electrodes, reactor operation, carbonate accumulation, cathode flooding, metabolic compatibility, flux matching, and system‐level coupling are analyzed. We also highlight the roles of artificial intelligence, multiscale modeling, smart control, techno‐economic analysis, and life‐cycle assessment in accelerating scale‐up and industrial translation. Overall, electrochemical–biological coupling provides a “capture‐convert‐valorize” route that integrates renewable‐electricity‐driven electrocatalysis with biomanufacturing, enabling CO 2 conversion into multicarbon, value‐added products and offering a promising platform for sustainable carbon recycling and carbon‐negative manufacturing.

A Self–Cascade Nanozyme of Metformin–Stabilized Amorphous Iron Oxide With Ultrahigh Fe(II) for Potent Tumor Therapy at Ultralow Dose

ABSTRACT The therapeutic efficacy of iron oxide nanozymes in cancer catalytic therapy has been severely constrained by the insufficient endogenous H 2 O 2 . To address this, constructing a self–cascading nanozyme that integrates oxidase (OXD) and peroxidase (POD) activities is highly desirable yet challenging, primarily due to the difficulty in stabilizing high–content of Fe(II) within nanostructures. Herein, we report the first synthesis of mesoporous amorphous iron oxide nanospheres (aFeO x ‑N) with unprecedented high Fe (II) level (66.59%) via the confinement coordination strategy using the strong N–donor metformin. This unique structure simultaneously exhibits robust OXD–like activity for in situ H 2 O 2 generation via a 2e − oxygen reduction pathway and enhanced POD–like activity for consequent •OH production. In vitro studies verified the aFeO x ‑N‑ss‑SiO 2 (encapsulated by SiO 2 outlayer containing ─S─S─ bonds for TME responsiveness) triggered ferroptosis and prominent cell death even under hypoxic conditions. Remarkably, a single ultralow dose (5 mg·kg −1 ) achieves a tumor inhibition rate of up to 96.19% in murine models, demonstrating exceptional therapeutic efficacy and biocompatibility. This work provides a novel and potent nanozyme platform for cascade catalytic tumor therapy.

Photo‐Generated ¹ O ₂ Triggers In Situ RNA Crosslinking for High‐Contrast Tumor MRI and Effective Tumor Suppression

ABSTRACT High‐contrast imaging and effective treatment of hepatocellular carcinoma (HCC) remain challenging, largely due to the limited tumor selectivity of existing contrast agents and the absence of stable and broadly conserved therapeutic targets. Herein, we report a photoactivatable molecular magnetic resonance/fluorescence (MR/FL) imaging probe for sensitive HCC imaging and potent tumor eradication that exploits the intrinsically RNA‐enriched nature of HCC. Upon light irradiation, singlet oxygen ( 1 O 2 ) triggers in situ furan–RNA crosslinking, prolonging its rotational correlation time ( τ r ), thereby markedly amplifying r 1 relaxivity. Notably, this light‐activated furan–RNA crosslinking strategy affords a 75% enhancement in tumor MR signal, significantly outperforming clinically used MR contrast agents. FL imaging further reveals prolonged tumor retention with detectable signals persisting for over 14 days, highlighting its potential for longitudinal monitoring of therapeutic response. Concurrently, photo‐generated 1 O 2 and following RNA crosslinking results in multiple cell death mechanism, including pyroptosis, ferroptosis and RNA interference, enabling sustained tumor suppression. This work presents the first photoactivatable RNA‐targeted MR/FL imaging probe and establishes a new paradigm that integrates molecular‐level MRI signal amplification, long‐term tumor retention, and multi‐pathway synergistic antitumor therapy for holistic HCC management.

Semiconducting Covalent Organic Frameworks Based on Spin‐Delocalized Trioxotriangulene Neutral Radicals

ABSTRACT Electrically conductive two‐dimensional covalent organic frameworks (2D COFs) have emerged as a versatile class of crystalline porous polymers with promising applications in electronics and energy storage. However, high electrical conductivity generally relies on post‐synthetic doping to generate charge carriers, which can compromise crystallinity, porosity, and structural homogeneity. Persistent neutral radical conductors provide an attractive alternative, as their unpaired electrons can generate free charge carriers without the need for counterions. Nevertheless, the incorporation of highly spin‐delocalized π‐radicals into COFs remains largely unexplored. Herein, we report the design and synthesis of imine‐linked 2D COFs incorporating spin‐delocalized trioxotriangulene (TOT) neutral radicals through complementary synthetic approaches. Direct use of a TOT radical derivative bearing amino groups affords a highly crystalline framework (TOT‐COF‐H) that exhibits semiconducting behavior ( σ RT = 1.2 × 10 −4 S cm −1 ), a reduced band gap ( E g = 1.09 eV), and a low activation energy (0.24 eV). This work demonstrates a viable strategy for integrating spin‐delocalized neutral radical building blocks into COFs, enabling the development of intrinsically conductive, porous, and crystalline organic frameworks without the need for extrinsic doping.

Beyond Simple Mimicry: Next‐Generation Geometric Architectures and Future Paradigms in Small‐Molecule and Macrocyclic Peptidomimetics

ABSTRACT Peptidomimetics have matured from motif‑based inhibitors into a structural engineering discipline that systematically translates peptide recognition surfaces into drug‑like scaffolds. Driven by the urgent clinical demand to overcome the inherent pharmacological liabilities of biomolecules, the field is undergoing a decisive Peptide‐to‐Small Molecule paradigm shift—functionally converting peptide‐derived recognition motifs into orally bioavailable synthetic therapeutics. This Perspective highlights how foundational geometric design principles—linear repetition, convergent fusion, and cyclization—define next‑generation architectures capable of targeting complex protein–protein interactions (PPIs). Repeating‑unit oligomers exemplify linear projection strategies, heterocycle‑centered scaffolds embody the convergent fusion of recognition motifs, and macrocyclic frameworks pre‐organize bioactive conformations while enabling access to non‑canonical topologies. Beyond simple mimicry, these architectures increasingly embrace dynamic responsiveness, aggregation remodeling, and universal multi‑structure platforms. We argue that the convergence of geometric logic with automated synthesis and AI‑driven design will transform peptidomimetics into a primary modality for decoding and therapeutically engaging the human interactome, including historically “undruggable” PPIs.

Peiran Wei

A Tautomeric Carbon Nitride Structure for Photocatalytic Overall Water Splitting

ABSTRACT Constructing type‐II heterojunctions is a prevalent strategy for enhancing the photocatalytic performance of polymeric carbon nitride (PCN). However, conventional PCN‐based type‐II heterojunctions are often limited by incoherent interfacial contacts, high charge‐transfer resistance, and poorly aligned energy levels with large band offsets, all of which impede interfacial charge transfer and degrade the redox capability of photocarriers. In this study, we report a pseudo‐resonance transformation strategy to selectively convert melon‐type carbon nitride (MCN) into a topologically analogous yet electronically distinct conjugated derivative (C─MCN). This process constructs a unique MCN/C─MCN tautomeric heterojunction​ featuring a chemically bonded, coherent, and dangling‐bond‐free interface. Carrier dynamics analysis reveals that this structural continuum significantly lowers the energy barrier for exciton dissociation while facilitating efficient interfacial charge transfer. As a result, the obtained tautomeric heterojunction exhibits outstanding photocatalytic overall water splitting performance, achieving a hydrogen evolution rate 2.3 and 2.6 times higher than that of pristine MCN and standalone C─MCN, respectively. This work establishes a new paradigm for fabricating dangling‐bond‐free polymeric heterojunctions, providing an efficient pathway toward solar‐fuel production.

Energy Transfer Catalysis Enabled by Multichannel Through‐Space Charge Transfer TADF Photosensitizers: [2 + 2] Photocycloaddition to Cyclobutane‐Fused Phosphindole 3‐Oxides

ABSTRACT Triplet energy transfer (TEnT) photocatalysis has emerged as a powerful tool for enabling mild and selective bond‐forming reactions. However, its generality remains limited by the intrinsic trade‐offs in existing photosensitizers (PSs). Noble metal (e.g., Ir, Ru) complexes offer high efficiency yet suffer from cost and sustainability concerns, while organic carbonyl sensitizers suffer from weak visible‐light absorption and short‐lived triplet states. Herein, we report heavy‐atom‐free organic PSs featuring a multi‐channel through‐space charge transfer (TSCT) architecture within a thermally activated delayed fluorescence (TADF) framework. A highly twisted donor‐acceptor topology enforces near‐complete frontier orbital separation, leading to ultralow singlet‐triplet energy gaps (Δ E ST down to 0.013 eV) and thereby enabling efficient spin interconversion. Consequently, these PSs simultaneously achieve high intersystem crossing (ISC) quantum yields, microsecond‐scale triplet lifetimes, and high triplet energies ( E T up to 63.7 kcal mol −1 ), rivaling those of state‐of‐the‐art noble‐metal systems. Leveraging these features, we demonstrate the first visible‐light‐driven intermolecular [2 + 2] cycloaddition of 1,3‐diphenylphosphindole 1‐oxides with alkenes and alkynes, enabling rapid access to structurally complex cyclobutane‐fused phosphindole 3‐oxides that hold potential value in drug screening but are typically difficult to obtain. Mechanistic studies support a TEnT pathway, in which minimal Δ E ST and efficient ISC are key to achieving high TEnT reactivity.

Positive Electrochemical Potentials Induce Enhanced Chemoselectivity and Activity in the Thermocatalytic Hydrogenation of 3‐Nitrostyrene

ABSTRACT Electrochemical promotion of catalysis is emerging as a powerful approach to control chemical reactions externally without complex catalyst modification, but this has mostly been used for substrates with a single reactive group so far. Herein, we demonstrate that this approach can induce full chemoselectivity in catalytic transformations of substrates with multiple functional groups. Specifically, we show that application of a positive electrochemical potential during the thermocatalytic hydrogenation (TCH) of 3‐nitrostyrene exclusively delivered one single product, 1‐ethyl‐3‐nitrobenzene, with six‐fold enhanced yield, while a complex product mixture was obtained at open circuit voltage. These effects resulted from the combined effects of a positive electrode polarization and acidification of the bulk solution through a concurrent hydrogen oxidation reaction (HOR). Surface‐enhanced infrared absorption spectroscopy and kinetic experiments showed that the positive polarization optimized the surface concentrations of reactants and the adsorption properties of 3‐nitrostyrene and hydrogenation products. Validation with additional reactants and catalyst implies a possible broader relevance of our findings beyond the initial system of 3‐nitrostyrene hydrogenation. Overall, our work provides fundamental insight into the effects of electrode polarization on thermal hydrogenation reactions and opens new opportunities to use electrochemical promotion to control chemoselectivity and activity.