ABSTRACT Acyl anion‐based umpolung is a foundational strategy in synthetic chemistry that enables reversal of the intrinsic electrophilic polarity of carbonyl compounds. Although acyl anion chemistry has been well developed, translating this polarity‐inversion concept to heavier main‐group congeners has remained elusive. Here we report the synthesis of a silicon/sulfur analogu of an acyl anion through a distinctive four‐electron reductive rearrangement of an arylthiotribromosilane precursor. Structural and computational analyses reveal a polarized Si═S interaction and lone pair at the silicon center, endowing it with acyl‐anion‐type electronic character. The resulting anion exhibits ambident nucleophilic reactivity of the silicon and sulfur centers. Reactions with Fe 2 (CO) 9 and organic azides demonstrate chemically accessible lone‐pair reactivity at silicon, whereas sulfur‐centered functionalization with chlorophosphine and chlorosilane electrophiles affords neutral acyclic silylenes. These findings establish a strategy for translating classical carbonyl umpolung concepts into low‐valent silicon chemistry and provide access to electronically cooperative main‐group frameworks featuring dual reactive sites.
ABSTRACT Substitution of C═C bonds with B–E units (E = N, O, P, etc.) provides a powerful strategy to modulate the electronic structure of π‐conjugated frameworks with minimal skeletal perturbation. However, precise control over excited‐state processes through heteroatom incorporation remains challenging. Herein, we present a modular one‐pot cascade combining 1,1‐bromoboration with double electrophilic borylation to construct fully conjugated BO‐fused PAHs with diverse fusion topologies. Photophysical and computational studies reveal that the distinct BO‐fusion patterns induce pronounced changes in frontier molecular orbital energies and excited‐state landscapes, which correlate with their divergent photosensitization behavior. Specifically, linear BO‐fusion compresses the S 1 –T 2 energy gap in anthracene derivatives, promoting triplet formation via an S 1 →T 2 →T 1 pathway. This strategy enables the development of a heavy‐atom‐free anthracene‐based sensitizer ( 9a‐H) that combines singlet‐oxygen generation with improved photostability. These findings establish BO‐fused PAHs as tunable platforms for triplet‐state engineering and photosensitization.
ABSTRACT Ladder‐type polycyclic conjugated hydrocarbons (PCHs) incorporating four‐membered rings represent a unique class of organic materials with local antiaromaticity and dearomatization induced by the four‐membered rings. [ N ]Phenylenes represent the only systematically synthesized series of PCHs containing multiple four‐membered rings or biphenylene units. Linear [ N ]phenylenes become increasingly unstable as the conjugation length extends. Here, we report the regioselective synthesis of linear [4] and [5]naphthylenes, representing the longest PCHs containing multiple four‐membered rings synthesized in solution to date. These structures were accessed through sequential catalytic arene oxanorbornene annulation reactions followed by aromatization. Raman spectroscopy and computation revealed significant dearomatization of naphthalenoid units and enhanced bond localization with increasing the conjugation length, contrasting with the typical bond delocalization trend in conventional conjugated molecules. These [ N ]naphthylenes exhibited high stability, markedly narrow blue emission profiles with very small Stokes shifts, high fluorescence quantum yields, as well as small shifts in the energy levels of frontier molecular orbitals upon increasing conjugation length. Skeletal flexibility was also observed in [4] and [5]naphthylene, but absent in [3]naphthylene, suggesting dynamic structural behaviors of longer [ N ]naphthylenes.
ABSTRACT Efficient suppression of photogenerated charge recombination remains a central challenge in photocatalytic water splitting. Bi 4 Ti 3 O 12 is a promising ferroelectric semiconductor for overall water splitting, yet its quantum efficiency is fundamentally constrained by weak polarization and sluggish carrier dynamics. Herein, we demonstrate that isovalent A‐site substitution provides an effective route to amplify the intrisinc polarization of Bi 4 Ti 3 O 12 through lattice regularization. Specifically, Sm substitution suppresses localization disorder by attenuating the stereochemical activity of Bi 3+ lone pairs, thereby reducing excessive octahedral tilting and enabling more coherent dipole alignment. The resulting enhanced ferroelectric polarization field markedly facilitates charge separation and carrier migration. In addition, post‐synthetic acid treatment tailors the surface termination and suppresses the self‐corrosion typically associated with bismuth‐based photocatalysts. Upon cocatalyst loading, the optimized Bi 4 Ti 3 O 12 ‐Sm photocatalyst achieves an efficient overall water splitting with an apparent quantum efficiency of 10.5% at 365 nm. This work establishes structural regularization as a viable design principle for enhancing ferroelectric polarization and advancing high‐performance photocatalytic systems.
Photocatalytic hydrogen peroxide (H2O2) synthesis from water and oxygen is a promising alternative to the anthraquinone process, but its efficiency depends on charge separation and reactant transport. Herein, we report a side chain strategy to regulate nanochannel microenvironments of hydrazone-linked covalent organic frameworks (COFs). Four COFs bearing H, OMe, OEt, or OEtOMe groups were prepared using the same benzotrithiophene node and hydrazone-linked framework. The alkoxy side chains tune pore polarity, accessible porosity, electronic properties, and water and oxygen adsorption. Among them, COF-Hz-OEtOMe exhibits the strongest water and oxygen affinity and favorable charge-separation behavior. It achieves an H2O2 production rate of 7240 µmol g-1 h-1 at the optimized catalyst loading in pure water and 22910 µmol g-1 h-1 with benzyl alcohol. A 1 L reactor using tap water and air accumulates 1.42 mM H2O2 after 4 h under natural sunlight. Experiments and theoretical calculations suggest that the conjugated framework promotes charge separation, while the alkoxy-functionalized nanochannels improve reactant adsorption and oxygen activation. Life cycle assessment (LCA) highlights that natural sunlight and larger-scale catalyst synthesis can reduce the calculated climate impact. These results demonstrate that pore-wall side chain engineering provides an effective strategy for regulating charge behavior and reactant transport in porous photocatalysts.
ABSTRACT Peptide coacervates formed via liquid–liquid phase separation (LLPS) have emerged as versatile cell‐like compartments for protocell studies and spatially confined catalysis. However, achieving remote, noninvasive modulation of their assembly‒disassembly lifecycle remains a key challenge. Here, we report a supramolecular design that enables light‐ and pH‐gated reversible coacervation of peptides through non‐covalent integration of spiropyran photoswitches. The mechanism relies on photoisomerization‐induced charge shift in spiropyran, which consequently modulates interpeptide electrostatic interactions to drive coacervate formation. Dissociation occurs reversibly via thermal relaxation upon the cessation of light, a process further regulated by pH, thereby enabling distinct on‐demand on‐ and off‐coacervation regimes. We validate this principle through systematic structural variations of both components, establishing a direct link between molecular design and phase behavior. Exploiting their reversible sequestration capability, we demonstrate that these coacervates serve as efficient light‑ and pH‐activated microreactors with OR logic gate functions that are capable of accelerating cascade reactions under dilute conditions and as dynamic reusable templates with cascaded OR – AND logic gate functions for recyclable synthesis of nanogels with tunable dimensions. This work establishes a versatile approach for dual‐mode regulation of peptide coacervates, opening avenues for the development of photo‐ and pH‐responsive microreactors and adaptive templates for material synthesis.
ABSTRACT Dynamic covalent chemistry and host–guest recognition are complementary tools for constructing adaptive molecular systems and functional materials, yet their integration has been hindered by the lack of general strategies for efficiently discovering host‐compatible dynamic‐covalent guests. Here we report a host‐directed screening strategy that directly identifies optimal imine guests from dynamic combinatorial libraries. Upon addition of the macrocyclic host, selective host–guest binding drives thermodynamically controlled library redistribution, leading to significant constitutional amplification of the preferred guests. A one‐pot workflow involving activation, complexation, deactivation, displacement, and readout enables precise quantification of this redistribution by simple one‐dimensional NMR spectroscopy. While 1 H NMR readout is well suited to smaller libraries, 19 F NMR offers clear advantages for more complex libraries, as demonstrated with a [5× 5] library. [2×n] library architecture further improves screening robustness by directing the major antagonistic response toward a channel excluded from candidate ranking. Although pillararene‐imine complexes have rarely been reported because of their weak binding, stepwise screening of three library sets identified imine guests for ethyl pillar[5]arene with association constants of up to (2.2 ± 0.1) × 10 3 M −1 . These findings establish host‐directed selection as a practical strategy for coupling molecular recognition with constitutional dynamics in adaptive systems and materials.
ABSTRACT Long‐wavelength multiple resonance (MR) emitters are desirable for high‐color‐purity organic light‐emitting diodes (OLEDs), yet conventional redshifting strategies often enhance excited‐state delocalization and vibronic coupling, leading to spectral broadening. In this study, we present a symmetry reconstruction strategy to break the trade‐off between spectral redshift and broadening in MR emitters. Unilateral and bilateral naphthalene‐fused π‐extension afford SN‐BN and DN‐BN, respectively, providing a direct platform for correlating excited‐state symmetry, vibronic coupling, and emission bandwidth. SN‐BN lowers the excited‐state energy but disrupts the balanced excited‐state hole–electron distribution, inducing partial charge‐transfer character and enhanced vibronic coupling. In contrast, DN‐BN expands the π‐conjugated framework and reconstructs excited‐state symmetry, thereby preserving short‐range charge‐transfer character while suppressing structural relaxation and vibronic coupling. Consequently, DN‐BN exhibits yellow emission at 545 nm with an ultranarrow full‐width at half‐maximum (FWHM) of 16 nm/0.07 eV and a photoluminescence quantum yield of 90% in toluene. The corresponding OLED achieves yellow electroluminescence at 560 nm with an FWHM of 24 nm, a maximum external quantum efficiency of 23.3%, and efficiency roll‐offs of 33.5% and 43.8% at 1000 and 100 000 cd m −2 , respectively. This work establishes symmetry‐reconstructive π‐extension as a promising design strategy for high‐color‐purity, long‐wavelength MR emitters.
ABSTRACT Photodynamic therapy (PDT) is noninvasive but lacks tumor specificity, while microRNAs (miRNAs) are highly specific biomarkers yet too low in abundance (pM‐nM) to directly trigger therapy. Here we report ECyTz , a microRNA‐21(miR‐21)‐activatable theranostic probe that achieves two‐stage signal amplification. In the first stage, one miR‐21 molecule catalytically activates multiple ECyTz probes through tetrazine‐mediated transfer (TMT) bioorthogonal chemistry (turnover number 5.6–41 at 10–100 nM), because the probe releases the active photosensitizer upon reaction while the intact miRNA remains to trigger further cycles. In the second stage, each activated photosensitizer generates abundant reactive oxygen species (ROS). ECyTz remains non‐fluorescent and photodynamically inert until miR‐21 triggers a proximity‐dependent inverse electron‐demand Diels–Alder reaction, restoring near‐infrared (NIR) fluorescence (27‐fold) and robust ROS generation. The probe exhibits strict sequence specificity, minimal dark toxicity, and potent antitumor efficacy in xenograft models (86.7% tumor growth inhibition with no observable systemic toxicity), with upregulation of the downstream tumor suppressor PTEN confirming on‐target activation. This modular miRNA‐actuated platform with tunable recognition sequences establishes a proof‐of‐concept for catalytic bio‐orthogonal signal amplification, offering a programmable strategy for precision tumor‐selective photodynamic therapy.
ABSTRACT Dicationic tetrylenes possess unique σ–acceptor properties but have long remained chemical curiosities because of their intrinsic instability and limited coordination chemistry. Chen and Zhang now transform these elusive species into practical, electronically programmable Z‐type ligands, enabling systematic tuning of platinum electrophilicity and catalysis ( https://doi.org/10.1002/anov.70024 ). This work establishes a new paradigm for Z‐type ligand design.
ABSTRACT Achieving precise and modulable chiral expression on molecular platforms is of great significance for the design and synthesis of chiroptical materials. Herein, we construct a supramolecular cavitand platform that enables programmable locking, switching, and rewriting of chiral information gated by light. A resorcin[4]arene‐based cavitand integrates multiple photoisomeriable stilbenes and alternating imidazole segments. By employing an outer‐wall binding strategy to bind multiple chiral carboxylic acids, it achieves efficient chirality transfer and enables the construction of a supramolecular chiral cavitand. Photoisomerization of embedded stilbene units, drives pathway‐dependent conformational transformations that govern chirality induction, retention, and erasure. Notably, different light channels (365/254 nm) enable distinct outcomes, including preservation of chiral host–guest complexes, disruption of propeller chirality, and complete guest release. Furthermore, chirality can be locked and retained in a propeller form after removing the chiral acids, demonstrating a light‐regulated chiral construction. The system further functions as a read‐write chiral information platform, allowing visualization, encryption, decryption, and erasure of chiroptical signals through programmable photochemical inputs. This work establishes a strategy for coupling photochemical control with supramolecular confinement, providing a proof‐of‐concept study of significant importance in chiral informatics.
ABSTRACT Photo‐assisted lithium‐sulfur batteries (PALSBs) can accelerate the sluggish redox kinetics of sulfur cathodes. However, the introduced light field inevitably complicates interfacial reactions, necessitating in situ evidence under realistic operating conditions. Here, we construct a TiO 2 /FePS 3 (TF) p–n junction bifunctional photoelectrode and employ a multiphysics‐coupled in situ x‐ray spectroscopic technique to elucidate light‐regulated catalysis from the interface into the bulk. Operando low‐energy XPS identifies potential interfacial catalytic sites. High‐energy operando XAFS is, for the first time, applied in PALSBs to track the K‐edge position of catalytic centers throughout cycling. The results show that the reversible dynamic valence evolution synchronizes with the stepwise sulfur redox process, revealing that photogenerated carriers and electrocatalytic electrons act cooperatively to promote polysulfide conversion. DFT calculations corroborate, from thermodynamic and kinetic perspectives, that illumination strengthens polysulfide anchoring and lowers the energy barriers of key conversion steps, consistent with the operando spectroscopic observations. Benefiting from this photoelectrochemical co‐regulation, the TF‐based PALSB maintains excellent reversible capacity and cycling stability under high sulfur loading and low electrolyte content. This work establishes a characterization paradigm for the rational design of high‐performance photo‐assisted Li–S cathodes.
ZUSAMMENFASSUNG Moleküle, die den pH‐Wert erfassen können, spielen seit über einem Jahrhundert eine zentrale Rolle in den analytischen und biomedizinischen Wissenschaften. Mit dem Aufkommen der Hyperpolarisations‐MRT ist eine schnelle, nichtinvasive und tomographische Bildgebung des pH‐Wertes innerhalb weniger Minuten zu einer realistischen und äußerst vielversprechenden Option für die klinische Diagnostik und Behandlung geworden. In dieser Arbeit zeigen wir, dass das pH‐abhängige Verhalten der MRT‐basierten pH‐Sonde 2‐Oxo‐4‐methyl‐3‐penten‐1,5‐disäure (OMPD), insbesondere die ausgeprägte Abhängigkeit ihrer 13 C‐chemischen Verschiebung vom pH‐Wert, auf einen reversiblen Cyclisierungsprozess zurückzuführen ist. Wir zeigen, dass die cyclische Lactolform von OMPD sowohl ihren geeigneten p K a ‐Wert (ca. 6,5) als auch ihre ausgeprägten pH‐abhängigen Änderungen der chemischen Verschiebung im NMR erklärt. Auf Grundlage dieser mechanistischen Erkenntnis entwickelten wir eine optimierte Synthese des Lactols und erzielten mittels Hyperpolarisation durch reversiblen Austausch mit Parawasserstoff eine mehr als 50.000‐fache Verstärkung des 13 C‐NMR‐Signals von OMPD (bei 1 T). Durch die Aufklärung der molekularen Grundlage des Sensorverhaltens von OMPD und die Etablierung einer effizienten, auf Parawasserstoff basierenden Methode zu dessen Hyperpolarisation stellt diese Arbeit einen bedeutenden Schritt hin zu einer breiteren präklinischen und klinischen Anwendung dar.
ZUSAMMENFASSUNG Eine robuste externe Steuerung der Spinkommunikation in molekularen Gerüsten ist für potenzielle Anwendungen in der Quanteninformationswissenschaft sehr erstrebenswert. In dieser Arbeit integrieren wir zwei Arten von Dithienylethen‐Einheiten (DTE) in Tris(2,4,6‐trichlorophenyl)‐methyl (TTM) basierte Diradikaloide und berichten über das erfolgreiche bistabile Schalten der optischen und magnetischen Eigenschaften des Moleküls. Die Bestrahlung der offenen Form mit sichtbarem Licht erzeugt bis zu 97 % die geschlossene Form, in der die Konjugation der zwei Radikalzentren zu einer Absorption über den gesamten sichtbaren Spektralbereich sowie zu einer Verdopplung der Singulett‐Triplett‐Energielücke führt. Diese Ergebnisse etablieren TTM/DTE‐Hybride als persistente und auf mehreren Ebenen schaltbare Diradikaloide.
ZUSAMMENFASSUNG Eine redoxneutrale Hydroaminoalkylierungsstrategie zur Synthese 1,1‐disubstituierter Aminocyclopropane aus Alkenen und Alkinen wurde entwickelt. Durch einfache solvolytische Aktivierung liefert die Umsetzung eines leicht zugänglichen, lagerstabilen Halbaminalvorläufers die Zielprodukte in ausgezeichneten Ausbeuten bei Raumtemperatur. Der hier vorgestellte Ansatz weist eine Substrattoleranz auf, die orthogonal zu klassischen Synthesen von Aminocyclopropanen ist. Seine Anwendung zur Herstellung von Bioisosteren pharmakologisch aktiver gem ‐α‐Dimethylamine führte zu verbesserten biologischen Eigenschaften.
ABSTRACT The development of advanced adsorbents for the selective and efficient recovery of gold from complex aqueous matrices is of paramount importance for sustainable resource recycling. Here, we report a phosphorus‐functionalized, quaternized ammonium cages (Phos‐QA‐Cage‐Cl) featuring multiple integrated binding sites, which delivers exceptional Au(III) uptake of up to 2331 mg g − 1 . The intrinsically cationic skeleton and Au‐affinitive phosphorus sites synergistically capture AuCl 4 − through combined electrostatic and coordination interactions. Thermal activation generates persistent radicals within the cage, which further enhance Au uptake by reducing Au(III) to nanoparticles, followed by halide‐promoted ripening of the nascent Au species. DFT calculations reveal the cooperative roles of noncovalent interactions, coordination bonding and radical‐assisted redox chemistry in driving efficient Au(III) capture. As a result, the cage exhibits rapid adsorption kinetics, high selectivity, and good recyclability in complex aqueous matrices. Leveraging its solution processability, a mixed‐matrix membrane based on polyvinylidene fluoride is fabricated, enabling efficient filtration and recovery of Au(III) (up to 95%) from dilute solutions, with a high permeate flux (87 L m − 1 h − 1 bar − 1 ). This work introduces a new class of functionalized porous cages for precious metal recovery and highlights the potential of integrating molecular design with solution processibility for environmental applications.
ABSTRACT The synthesis of metal hydrides is constrained by a fundamental paradigm: metals are believed to react only with molecular hydrogen (H 2 ) to form hydrides, not directly with protons (H + ) in solution. This necessitates an indirect route through the production and compression of high‐purity H 2 gas. We present an alternative synthetic route by repurposing acidic corrosion and hydrogen embrittlement to engineer an in situ hydrogen‐trapping cage (HTC) within metals. The HTC enables direct proton‑to‑hydride conversion under mild conditions (ambient pressure, ∼70 % lower temperature). By using protons directly from acids as the hydrogen source, this approach bypasses the need for high‐pressure H 2 gas, enabling hydride synthesis at ambient pressure and substantially lower temperatures. The process simultaneously constructs a defect‐rich microstructure in situ, facilitating rapid ion transport. Guided by the universal criterion |Δ P eq | > Δ P ph , we demonstrate the versatility of our method by synthesizing a library of over 20 hydrides, including LiH and NaH; its functional power is exemplified by a cage‐rich HTC‐TiH 2 electrocatalyst, which achieves a nitrate‐to‐ammonia current density of 1.07 A cm −2 via enhanced H − mobility. This work demonstrates a strategy that couples hydrogen capture, stabilization, and conversion within a single material system, providing a potential route for sustainable hydrogen management.
ZUSAMMENFASSUNG Frequenzbereichs‐Fourier‐Transformations‐THz‐ESR‐Spektroskopie ermöglicht einen direkten Zugang zu kinetisch eingefrorenen High‐Spin ‐( HS )‐Zuständen in Eisen(II)‐ Spin‐Crossover ‐(SCO)‐Komplexen. Mithilfe des temperaturinduzierten Einfangens angeregter Spinzustände (temperature‐induced excited spin‐state trapping, TIESST) wird die elektronische Struktur des HS ‐Zustands bei tiefer Temperatur trotz eines diamagnetischen Low‐Spin ‐( LS )‐Grundzustands zugänglich. Unterstützt durch Ab‐initio ‐Berechnungen erlauben feldabhängige Spektren die Aufspaltung des HS ‐Grundzustandsmultipletts zu entschlüsseln und liefern Hinweise auf eine Spin‐Phononen‐Kopplung, die durch einen „avoided‐crossing“‐Hamilton‐Operator beschrieben wird. Die THz‐ESR‐Spektroskopie quantifiziert darüber hinaus den verbleibenden HS ‐Anteil (γ HS ) und detektiert Verschiebungen magnetischer Übergänge, die von den Spinzuständen der umgebenden Matrix abhängen. Diese Ergebnisse zeigen, dass HS ‐Zentren in gemischten HS / LS ‐Zuständen unterschiedliche lokale Gitterumgebungen erfahren, und eröffnen einen experimentellen Zugang zum Einfluss der Spinzustandsverteilung auf SCO‐Prozesse. Kooperative Schaltszenarien, einschließlich Domänenbildung und alternierender HS / LS ‐Anordnungen, lassen sich auf diese Weise unterscheiden, so dass feldabhängige THz‐ESR‐Spektroskopie einen direkten Zugang zu gitterabhängigen Effekten in SCO‐Materialien bietet.
ABSTRACT Biomolecules are central to disease onset, diagnosis, and treatment, yet materials capable of actively interacting with biological targets remain limited. Gallium‐based liquid metals and their derivative composites possess a metallic liquid core, a dynamic oxide interface, and releasable metal species, which support diverse molecular interactions and regulatory processes. However, current advances remain scattered across different biomedical applications and are often discussed mainly from a materials perspective. Here, we propose liquid metal molecular medicine (LMMM) as an interdisciplinary framework that connects liquid‐metal active components and molecular mechanisms with biomedical functions. This Review outlines the mechanistic basis of LMMM and organizes current research into eight subfields: molecular diagnostics, targeted drug delivery, nucleic‐acid regulation and prospects, antibiosis, immunology, enzymology, cell repair, and regenerative medicine. By interpreting these applications from the perspective of molecular interactions, LMMM complements existing application‐centered reviews and highlights the distinctive role of liquid metals as active molecular interfaces. Key scientific and translational challenges are also discussed.
ABSTRACT Aqueous microdroplets in a bulk fluorous oil medium confer unique behavior on self‐folding water‐soluble synthetic receptors (deep cavitands). The lipophilic, yet water‐soluble cavitands self‐assemble at the water‐oil interface, coating the surface of the microdroplet rather than diffusing through the interior. By combining the receptors with indicator dyes that bind in the host cavity, simple optical detection of the molecular recognition event is possible, as is spatiotemporal monitoring of the receptors in the droplets. The interfacial self‐assembly of the host–guest complex is driven by hydrophobic association between the individual cavitand molecules, and controlled molecular recognition of suitable guest molecules can be observed. By exploiting droplet merging experiments, the cavity‐based and aggregative molecular recognition behaviors can be differentiated. The system provides a unique insight into supramolecular aggregation, interfacial behavior, and molecular recognition at water‐oil interfaces.
