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.
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 Precious metal nanoparticles generally aggregate through Ostwald ripening in the absence of anchoring sites, whereas in the presence of suitable coordination environments, they can disperse into thermodynamically stable single‐atom (SA) with chelate structures. Herein, an unexpected staggered transformation between nanoparticles and SAs on nitrogen‐doped carbon (CN) is reported. M (M = Rh, Ir, Pt)‐Zn intermetallic compound (IMC) nanoparticles together with Ru SAs were initially constructed on CN at 800 °C, and were transformed into M SAs and Ru nanoparticles after annealing at 1000 °C. Metadynamics simulations indicate that Ru─N bond cleavage followed by Rh refilling is kinetically accessible at 1000 °C, with a free‐energy barrier of ∼2.30 eV. The resulting Rh 12 Ru 1 + Rh–N configuration is structurally favored because of its higher d ‐band filling and stronger covalent Rh–N interactions, under which Rh tends to adopt an electronically rigid coordination environment. Benefiting from the cooperation between Rh SAs and Ru nanoparticles, a mass activity of 62.1 A mg −1 was achieved for formic acid electrooxidation (FAOR), which is four times higher than that of Rh SAs (15.9 A mg −1 ). This work provides new insights into the direction of atomic shuttling between precious metal species.
Metal halide perovskite (MHP) single crystals are promising for optoelectronic applications, yet their surfaces suffer from severe ion migration-related degradation. Herein, a 2D/1D stacking layer is explored to stabilize the crystal/electrode interface. In addition to providing a dense barrier layer, the inserted 2D perovskites can modulate the microscopic morphology and coverage ratio of the overlying 1D perovskite layer. Through tailoring the 2D/1D stacking layer, interface iodide migration is suppressed markedly, extending the T90 lifetime of single-crystal perovskite solar cells (PSCs) from 450 h to 2500 h, which significantly exceeds previously reported values. Besides, the reverse-bias-induced performance decay can be recovered substantially, indicating effective hindrance of irreversible iodide ion migration across the perovskite/electrode interface. Finally, the surface iodide vacancies and nonradiative recombination loss are mitigated, increasing the power conversion efficiency (PCE) from 23.2% to 25.5%, which is among the highest value for single-crystal PSCs. Since interface ion migration is a universal issue for both polycrystalline films and single crystals, our strategy is instructive for optimizing diverse perovskite optoelectronic devices.
Efficient separation of xylene isomers remains a significant challenge due to their nearly identical physicochemical properties. Here, we report a dual locking strategy in an aluminum-pyrrolic framework (Al-PyDC) with V-shaped ligand featured AlO6 chains and pyrrole dual recognition sites that simultaneously stabilize the V-shaped meta-xylene (mX). This dual-locking effect promotes dense packing of mX within confined channels, resulting in a high adsorption capacity for mX (4.0 mmol g-1), which is much higher than that for ortho-xylene (oX, 2.5 mmol g-1) and para-xylene (pX, 2.0 mmol g-1). The simulations and solid-state NMR spectroscopy further confirmed that mX experienced stronger locking interactions with the AlO6 chains and pyrrolic ligands compared to pX. Notably, the dual locking effect was temperature-dependent, and elevated temperature accelerated molecular diffusion, thereby weakening the effectiveness of the recognition. Hence, Al-PyDC achieved an excellent mX/pX selectivity of 8.0 in vapor-phase breakthrough measurements at ambient temperature (303 K), which outperformed most of the MOF counterparts. Additionally, the isomorphic CAU-10-H with V-shaped AlO6-phenyl-AlO6 dual locking sites was employed as a control material to elucidate the role of active-site in molecular recognition. This dual locking strategy offered an effective approach for enhancing the adsorption capacity and selectivity for challenging isomer separations.
The marine bacterial genus Aquimarina comprises diverse members with numerous natural product biosynthetic gene clusters but few characterized compounds. Here we report a novel class of lipopeptides with exceptional antibiotic activity, named marinocyclins, isolated from Aquimarina megaterium EL43 associated with the octocoral Eunicella labiata. The major congener marinocyclin A exhibited potent and uniform activity against a broad panel of drug-resistant gram-negative and gram-positive pathogens, including ESKAPE bacteria. The natural product efficiently compromised the outer and inner bacterial membranes, leading to rapid cell permeabilization and lysis. This activity profile was mediated by the ability to bind lipopolysaccharides, anionic phospholipids enriched in bacterial membranes, and peptidoglycan precursors. Eukaryotic cytotoxicity required higher doses than antibacterial activity. Genomic data suggest a nonribosomal biosynthetic origin for marinocyclins. These findings position marinocyclins as a promising new scaffold for antibiotic development and highlight the potential of Aquimarina spp. as a source of novel antibiotics. Further medicinal chemistry optimization of marinocyclins could enhance their prokaryotic selectivity to generate leads for treating infections caused by drug-resistant pathogens.
The photocatalytic acetylene hydrochlorination with H2O as hydrogen source and Cl- as chlorine source in seawater is a highly promising alternative to traditional thermocatalytic acetylene hydrochlorination, but seriously suffers from poor performance due to the rapid recombination of photogenerated electrons and holes as well as the sluggish redox kinetics caused by low H+ and Cl- concentrations. Here, we report an O2-accelerated photocatalytic acetylene hydrochlorination in seawater, where the O2 serves as an efficient electron acceptor for rapidly consuming photo-generated electrons. Consequently, the as-fabricated tubular carbon nitride photocatalyst (MTA-C3N4) delivers a substantially enhanced vinyl chloride monomer (VCM) production rate of 567.0 µmol gcat -1 h-1 under 420 nm light-emitting diode (LED) irradiation in simulated seawater with O2, which is ∼66-fold higher than that without O2. Even in natural seawater, the MTA-C3N4 maintains a stable VCM production rate of 433.3 µmol gcat -1 h-1 over 10 days. Mechanistic studies reveal that O2 acts as an electron acceptor to suppress charge recombination and promote the formation of holes, thereby accelerating the hole-driven chloride oxidation kinetics to generate *Cl for selective acetylene hydrochlorination. This work not only reveals the vital role of molecular oxygen in photoredox kinetics, but also provides an appealing strategy for enhancing photocatalytic performance.
Terpenoids represent one of the most structurally diverse and biologically relevant families of natural products, yet the development of controllable biomimetic synthetic strategies using bulk feedstocks remains a critical challenge. Isoprene, an abundant and atom-economical building block, holds great promise for terpenoid synthesis, but its four electronically and sterically similar olefinic carbons generally lead to poor regioselectivity and uncontrollable chemoselectivity in catalytic transformations. In this study, we reported a nickel-catalyzed chemodivergent telomerization and hydrofunctionalization reaction for constructing terpenoids, wherein precise ligand control enables selective reactivity tuning. Leveraging the in situ formation of benzyl group from hydrazone-mediated carbonyl umpolung reaction, telomerization is promoted by triarylphosphine ligand featuring both large steric hindrance and electron-donating characteristics, while hydrofunctionalization benefits from the combination of less bulky, electron-withdrawing triarylphosphine ligand and BEt3. Mechanistic studies and density functional theory calculations validate the chemoselectivity governed by ligand sterics and electronics, as well as the role of BEt3 in enhancing regioselectivity. Moreover, this protocol created a series of value-added terpenoids, all of which are amenable to further structural derivatizations. This mild, operationally simple catalytic manifold enables facile access to unnatural terpenoids and broadens the accessible chemical space of terpene frameworks.
Birefringent crystals that simultaneously exhibit large optical anisotropy and wide band gaps are highly desirable for advanced photonic technologies, yet these properties are often mutually constrained because structural features that enhance birefringence often compromise optical transparency. Herein, we report four new hybrid niobium oxyfluoride phenanthroline compounds, [Hphen]NbOF4∙H2O (NP1), α-[Hphen]NbOF4 (NP2), β-[Hphen]NbOF4 (NP3), and [Hphen]2NbOF5 (NP4), obtained through systematic variation of synthetic conditions. Thermal dehydration of centrosymmetric hydrated phase NP1 yields noncentrosymmetric (NCS) dehydrated phase NP2 through reversible crystal-to-crystal transformation, with birefringence increasing from 0.354 to 0.419 at 546 nm. Further optimization affords NP3, which exhibits an enhanced second-harmonic generation (SHG) response of 1.2 × KDP, compared with 0.09 × KDP for NP2. Strikingly, transformation from a one-dimensional chain-type niobium oxyfluoride framework (NP1-NP3) to a zero-dimensional structure of isolated NbOF5 units (NP4) removes geometric constraints on phenanthroline alignment, enabling near-coplanar arrangement of π-conjugated chromophores and a record-high birefringence of 0.618 at 546 nm for a Nb-based crystal. All four compounds retain wide optical band gaps of 3.2-3.3 eV, demonstrating that giant birefringence and UV transparency are simultaneously achievable within a single material family. These results establish framework dimensionality as a viable strategy for overcoming the trade-off between optical anisotropy and transparency.
The activity-stability trade-off in oxygen reduction reactions (ORR) fundamentally limits the practical development of Zinc-air batteries (ZABs) and fuel cells. Here, we address this long-standing challenge through spatial electronic engineering that enables dual d-p orbital hybridization within a Pt-based ternary alloy. The resulting PtGaGe catalyst exhibits exceptional alkaline ORR performance, achieving a mass activity of 1.79 A·mgPt -1 and a half-wave potential of 0.90 V (vs. RHE)-both surpassing commercial Pt/C and most previously reported Pt-based catalysts. When integrated into a ZAB, it reaches a peak power density of 207.6 mW·cm-2 and maintains steady operation for over 200 h at 10 mA·cm-2, highlighting outstanding durability under practical operating conditions. Density functional theory (DFT) calculations reveal that dual d-p hybridization induces spatial electron redistribution between Pt and Ga/Ge sites, modulating the Pt d-band center and facilitating O─O bond activation while suppressing catalyst degradation. This synergistic electronic regulation simultaneously improves catalytic activity, stability, and Pt utilization efficiency. This work establishes a mechanistic paradigm for electronic-structure engineering in high-performance ORR electrocatalysts.
Dysfunction of the microtubule-associated protein Tau is a central feature of Alzheimer's disease and related tauopathies, yet how site-specific lysine modifications modulate the functional and pathological states of Tau remains poorly understood. Here, we combine protein semi-synthesis with segmental isotope labelling and NMR spectroscopy of full-length Tau, to dissect how lysine acetylation and carboxymethylation within the microtubule-binding region of Tau regulate its interactions with tubulin, microtubules, and amyloid assembly. Site-specific modification at lysine 294 delays Tau-mediated tubulin polymerization and fibril formation, whereas acetylation at lysine 311 exerts more moderate effects, but alters fibril morphology. NMR spectroscopy of segmentally isotope-labelled Tau variants indicates that single lysine acetylation does not measurably weaken Tau binding to pre-formed microtubules; however, bivalent acetylation reduces microtubule binding, possibly by cumulative charge neutralization. Together, these results indicate that lysine acetylation redistributes Tau between functional states in a site- and valency-dependent manner. Our study helps to establish a mechanistic framework linking combinatorial lysine modifications to Tau dysfunction and highlights the utility of region-resolved structural approaches to decipher posttranslational modification-dependent equilibria in intrinsically disordered proteins.
The interaction between the hybrid component of self-assembled monolayers (SAMs) and the perovskite precursor could delay the crystallization process, resulting in high-quality perovskite film and highly efficient perovskite solar cells (PSCs). However, the intensity of interaction affects more precise control of crystallization speed. Herein, we introduce two pyridinium cation species to compare the intensity of their interaction with iodide. Our systematic investigation reveals that the more electron deficient 1-methyl-4-(trifluoromethyl)pyridinium (CF3Py+)-based hybrid SAM enables a champion power conversion efficiency (PCE) of 27.07% (certified 26.8%) for a 0.06-cm2 PSC, surpassing hybrid 1-methylpyridinium (Py+)-based device (26.42%) and pure 4PADCB-based device (25.12%). The impressive PCE stems from fine-tuning of crystallization speed through more intensive interaction between CF3Py+ and I-. Moreover, the stronger interaction inhibits iodide migration, which improves the light and thermal stability of the optimized PSCs. Our work demonstrates an effective approach to strengthening the interaction between pyridinium cations and iodide by incorporating an electron-withdrawing group into the aromatic core, providing crucial insights into the manipulation of perovskite film crystallization.
Ferroelectric materials have emerged as a promising class of optoelectronic candidates, due to their strong light-polarization couplings that lead to fascinating physical attributes. Especially, photoexcited pyroelectricity originating from light-induced variation of spontaneous polarization (Ps) holds potentials for ultra-broadband photodetection even up to long-wave infrared optical region. For the first time, we present the full-wavelength switchable photoexcited pyroelectric effects in a two-dimensional perovskite ferroelectric, (4-ethylanilinium)2(ethylammonium)2Pb3Br10 (1), covering ultraviolet to long-wave infrared spectral range. It is a high-temperature ferroelectric (Tc = 390 K) with superior pyroelectricity, including large pyroelectric coefficients and figure-of-merits. Strikingly, robust full-wavelength photoexcited pyroelectric responses are obtained in 1 under irradiation from ultraviolet (266 nm) to long-wave infrared (12.5 µm) region, far beyond its intrinsic optical bandgap. These Ps-dependent photoactivities can be electrically switched and controlled by electric poling. Thus, crystal-based device of 1 allows ultrabroadband photodetection, as verified by highly-sensitive response to human radiation. As the first report on full-wavelength photoexcited pyroelectricity in perovskite ferroelectrics, our study highlights a promising strategy for new-generation broadband optoelectronic devices.
Conventional strategies to address sluggish polysulfide conversion and the shuttle effect have primarily focused on interactions between sulfur anions and catalytic centers, while largely neglecting the enrichment and transport of lithium ions at the cathode. Herein, we report a niobium (Nb) atomic catalyst anchored on graphdiyne (Nb-GDY) that enables a unique dual-end binding mechanism for the simultaneous regulation of polysulfide conversion and lithium-ion transport kinetics. Density functional theory calculations reveal pronounced electronic coupling between Nb─S and Li─C pairs, creating synergistic binding sites that immobilize LiPSs while lowering the energy barriers for their transformation. This mechanism is corroborated by x-ray photoelectron spectroscopy and comprehensive in situ characterizations, which demonstrate significantly accelerated electrode kinetics and efficient Li+ flux. Consequently, the Nb-GDY-based cathode exhibits exceptional high-rate capability and long-term durability, achieving a high capacity of 724 mAh g-1 at 10 C and maintaining stable operation over 1200 cycles at 5 C with a low-capacity decay of 0.025% per cycle. Our research ingeniously combines dual ends binding, activating the synergistic interaction between atoms and the substrate, providing a new concept for the management of multi-species transport for high energy density Li-S batteries.
Peloruside A, a polyketide macrolide identified in the marine sponge Mycale hentscheli, is a promising anticancer drug candidate due to its ability to stabilize tubulin at a nontaxoid binding site. Substantial efforts were made to improve the supply of this scarce substance through chemical synthesis and mariculture, however, sustainable production has yet to be achieved. Recent microbiome sequencing suggested that bacterial producers are responsible for all M. hentscheli bioactive compounds, but the identity of the peloruside producer remained unknown. Furthermore, a candidate peloruside polyketide synthase (PKS) was identified in silico, but its highly aberrant architecture prevented a confident biosynthetic prediction for the pharmacologically important exocyclic double bond. Here, we reveal an unusually complex modular PKS pathway comprising nonelongating ketosynthases (KSs), two internal thioesterases (TEs), and an acetyl coenzyme A ligase that orchestrate O-acetylation/elimination, acetyl-CoA recycling, and configurational proof-reading to facilitate selective Z-double bond incorporation. The first internal TE falls into a previously characterized O-acylating TE family but contains key amino acid substitutions that facilitate bifunctional acylation/elimination activity. Furthermore, we identified the peloruside producer as 'Candidatus Pelorusia occulta', a member of the biochemically underexplored Lentisphaeria class within the phylum Verrucomicrobiota. This work provides the biochemical and microbiological foundation for heterologous peloruside production.
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 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.
Efficient suppression of photogenerated charge recombination remains a central challenge in photocatalytic water splitting. Bi4Ti3O12 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 Bi4Ti3O12 through lattice regularization. Specifically, Sm substitution suppresses localization disorder by attenuating the stereochemical activity of Bi3+ 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 Bi4Ti3O12-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.
