Sulfilimines are emerging as valuable functional group in modern medicinal chemistry. Yet, their catalytic preparation is underexplored compared to sulfoximines. Here, the iron-catalyzed synthesis of 14 examples of unprotected sulfilimines in good yields, under aerobic atmosphere and at room temperature, is described. Interestingly, this catalytic procedure is also efficient for the late-stage functionalization of penicillin G derivative.

Iron-catalyzed nitrene transfer reactions have gained significant interest in recent decades. However, the catalytic synthesis of sulfilimines, the aza-analog of sulfoxides, remains underexplored, and the few examples published only describe protected nitrene transfer reactions. With the rising importance of sulfoximines in medicinal chemistry, sulfilimines are also emerging as valuable targets for drug discovery and bioactive molecule development. Here, an iron-catalyzed NH-sulfilimination reaction using a bioinspired iron complex, [Fe(II)MeTPEN](OTf)2, in combination with PivONH3(OTf) as nonprotected nitrene donor is reported. The reaction operates under atmospheric conditions at room temperature and exhibits broad substrate scope, with yields exceeding 80% for most sulfide compounds. The method demonstrates high selectivity, functional group tolerance, and scalability. Notably, the sulfilimination of penicillin G methyl ester is successfully performed, suggesting potential applications in late-stage drug functionalization.

This work demonstrates the on-liquid surface synthesis of crystalline 2D polyimine films by leveraging a fluorinated surfactant and a binary solvent mixture of DMAc-H2O. In situ grazing incidence X-ray scattering reveals stepwise monomer adsorption, preorganization, and polymerization, accompanied by lattice expansion from 3.4 to 5.3 nm. The resulting films exhibit well-defined hexagonal pores, mechanical robustness, and pronounced negative surface charge and deliver a power density of 15.99 W m−2 in osmotic energy conversion.

On-water surface synthesis has emerged as a powerful approach for constructing thin-layer, crystalline 2D polyimines and their layer-stacked covalent organic frameworks. This is achieved by directing monomer preorganization and subsequent 2D polymerization on the water surface. However, the poor compatibility of water with many organic monomers has limited the range of accessible 2D polyimine structures. Herein, the on-liquid surface synthesis of crystalline 2D polyimine films from a water-insoluble, C3-symmetric monomer previously deemed incompatible with aqueous systems is reported. In situ grazing incidence X-ray scattering reveals a stepwise evolution of monomer adsorption, preorganization, and 2D polymerization assisted by the fluorinated surfactant monolayer, leading to the formation of large-area, face-on-oriented 2D polyimine films. Notably, a pronounced lattice expansion from 3.4 nm in the monomer assembly to 5.3 nm in the 2D polyimine framework is observed, highlighting the templating effect of the preorganized monomers in defining the final crystallinity. The representative 2DPI-TCQ-DHB is obtained as free-standing thin film with well-defined hexagonal pores, mechanical robustness, and a negatively charged surface (zeta potential: −58.8 mV). Leveraging these structural characteristics, it is integrated 2DPI-TCQ-DHB films into osmotic power generators, achieving a power density of 16.0 W m−2 by mixing artificial seawater and river water, surpassing most nanoporous 2D membranes.

Nearly identical molecular modifications of two differently shaped cuprous oxide via click chemistry lead to a striking divergence in product selectivity in CO2 electrolysis—favoring either methane or C2+ compounds. This contrast reveals dual roles of the organic layer : forming distinct functional sites that act synergistically and disrupting copper atom ordering.

Molecular fabrication of metal surfaces has potential to harness diverse surface processes, such as CO2 electrolysis on copper. CO2 reduction is influenced not only by the local environment of the active copper atom but also by the surface atomic order, surface dynamics under electrode polarization, and mass transport. CO2 reduction on two types of Cu2O-derived Cu metal, modified with chemically identical organic layers, is studied. Surface click chemistry enables uniform modification, precisely replicating the surface morphologies of 2D-packed and dispersed nanocubic Cu2O. In both types of catalysts, the modification affects CO2 reduction, but with markedly different selectivity. On 2D-packed Cu2O, the modified organic layer forms two distinct functional domains, one promoting proton reduction and the other facilitating CO adsorption, on a continuous copper surface. These domains cooperatively promote the formation of C2+ products. In modified nanocubic Cu2O, where a limited number of copper atoms are enclosed in the organic layer shell, the crystal regularity of reduced Cu is disrupted significantly inhibiting CC bond formation. Assisted by proton transport through organic layer, this surface instead selectively produces methane. These results highlight the multifunctional effects of molecular modification, which creates distinct yet cooperative domains and induces surface atom restructuring.

Exploring the reactivity of the trivalent U(NHDIPP)5K2(THF)4 (1) leads to the formation of uranium imido complexes. Treating 1 with 18c6 causes spontaneous oxidation and the formation of [U(NDIPP)(NHDIPP)4][K(18c6)(THF)]2 (2). Oxidation of 1 or 2 results in the formation of U(NDIPP)2(NHDIPP)2 (3). This species is in equilibrium with the previously established U(NDIPP)3 and is trapped sterically or electronically.

Exploring the reactivity of the trivalent uranium penta(anilido) species, U(NHDIPP)5K2(THF)4 (1) (DIPP = 2,6-diisopropylphenyl), leads to the formation of uranium imido complexes. Treating 1 with 2 equivalents (equiv) of 18-crown-6 (18c6) causes spontaneous oxidation and the formation of [U(NDIPP)(NHDIPP)4][K(18c6)(THF)]2 (2). Oxidation of 1 with AgBPh4, or 2 with I2, results in the formation of the uranium(VI) bis(anilido) bis(imido) compound, U(NDIPP)2(NHDIPP)2 (3). This species is in equilibrium with the previously established U(NDIPP)3 and is trapped with one equiv of of 2,2′-bipyridine (bpy) to form (bpy)U(NDIPP)2(NHDIPP)2 (4). All species are analyzed by 1H NMR spectroscopy and X-ray crystallography, where possible.

This work presents a defect-site activation strategy, in which anchoring Ir single atoms onto the highly strained defects of Pd metallene generates synergistic PdIr sites, leading to a dramatic enhancement in the ethanol oxidation reaction.

The development of highly efficient electrocatalysts for the ethanol oxidation reaction (EOR) is critical to the commercialization of direct ethanol fuel cells, which represent a promising clean energy technology. 2D palladium metallenes (Pd MLs) have recently emerged as attractive electrocatalytic materials with the potential to replace conventional Pt-based catalysts, owing to their exceptionally high surface-to-volume ratio. However, the practical application of Pd MLs requires the construction of efficient active sites and the mitigation of stability issues associated with their defective structures. In this study, a defect-site activation strategy is proposed involving the anchoring of single iridium (Ir) atoms onto the high-strain defect regions of ultrathin Pd MLs, which significantly enhances their EOR performance. The optimized catalyst, Ir0.59/Pd ML, featuring atomically dispersed Ir, achieves a remarkable mass activity of 1085.45 mA mg−1 toward EOR—≈ 12.8 times higher than that of pristine Pd MLs. Detailed mechanistic studies indicate that the enhancement arises from the formation of synergistic PdIr sites within the defect regions. These sites concurrently improve both EOR activity and poison tolerance through electronic modulation. This work demonstrates the potential of atomic-level engineering of intrinsic defects in metallene materials for the rational design of advanced 2D electrocatalysts.

This review summarizes the main factors affecting Fe–N–C catalysts for ORR: activity depends on active site structure, electronic configuration, and porosity, while stability is limited by metal leaching, carbon degradation, and inactive phase formation. Strategies like porosity engineering, dual-metal doping, protective encapsulation, advanced synthesis, and post-treatments are discussed to design highly active and durable catalysts.

The oxygen reduction reaction (ORR) is a key process in energy conversion devices such as fuel cells and metal-air batteries, yet its slow kinetics significantly limit overall performance. Current ORR practicality largely relies on the utilization of platinum-group metals, facing challenges in scarcity, high cost, and poisoning tolerance. Iron–nitrogen–carbon (Fe–N–C) catalysts have emerged as promising platinum-group-metal-free alternatives due to their low cost, tunable structure, and strong ORR activity in pH-universal environments. These atomically dispersed Fe–N x sites have wide tunability in electronic state and local coordination, exhibiting great potential in activity/stability enhancement and selectivity switching. However, challenges such as Fe leaching, carbon corrosion, and the formation of inactive phases limit their durability. This review outlines the main factors influencing the activity and stability of Fe–N–C catalysts and summarizes recent strategies for improvement, including dual-metal doping, porosity engineering, advanced synthesis methods, and protective encapsulation. These insights provide a pathway for designing next-generation ORR catalysts for sustainable energy applications.

A boron-catalyzed α-aminoxylation of carboxylic acids enables rapid access to sterically congested α-(aminoxy)carboxylic acids. Photoexcited diboron enediolates transfer energy to O-sulfonylhydroxylamines, triggering SO bond cleavage to generate N-oxyl radicals. This unusual reactivity contrasts with conventional NO bond cleavage pathways and is compatible with pharmaceuticals and amino acid–derived agents, allowing concise synthesis of β-amino acid analogs and application for peptide chemistry.

A boron-catalyzed direct α-aminoxylation of carboxylic acids is developed, providing rapid access to unique β-amino acid analogs, namely α-(aminoxy)carboxylic acids. Upon visible-light irradiation, catalytically generated diboron enediolates undergo photoexcitation and energy transfer to O-sulfonylhydroxylamines, causing a novel SO bond cleavage pathway. This reactivity of the O-sulfonylhydroxylamine contrasts sharply with the conventional NO bond cleavage typically induced by single-electron reduction. The resulting N-oxyl radicals exhibit high reactivity, enabling the synthesis of sterically congested N-alkyl-α,α-disubstituted-α-(aminoxy)carboxylic acids. The protocol is applicable to the aminoxylation of pharmaceutical carboxylic acids. Beyond simple N-protected aminoxylating agents, α-amino acid-derived variants are also applicable, allowing for the construction of di- and tripeptides. Furthermore, leveraging the direct use of carboxylic acids, sequential condensation with glycine methyl ester enabled straightforward peptide elongation.

Carbene-stabilized dithiolene zwitterion, as a redox-active frustrated Lewis pair, can mediate the B─H bond activation of catecholborane via hydride-coupled reverse electron transfer processes. This discovery represents the first experimental evidence of the FLP-mediated B─H activation via net proton transfer. It may provide a novel route for the activation of E─H bonds in p-block element(E)-based species.

The CAAC-stabilized dithiolene (L0) zwitterion (1), an unusual redox-active intramolecular frustrated Lewis pair (FLP), activates the B─H bond of boranes via hydride-coupled reverse electron transfer processes. The reactions of 1 with catecholborane in THF give a zwitterionic bis(dithiolene)-based spiroborate (2), in which one sulphur atom (at the C2 carbon) bonds to the (CH2)4OB(O)2C6H4 chain due to the catecholborane (CatBH)/Sthiourea Lewis pair-mediated THF ring opening. In addition to 2, [CAAC(H)]+[(Cat)2B]−, (3), CAAC(H)2, (4), and [CAAC(H)3]+[(Cat)2B]−, (5), are also isolated from these reactions. In addition to synthetic, structural, and spectroscopic data, a plausible reaction mechanism is proposed. This finding provides compelling experimental evidence of FLP-mediated B─H activation via net proton transfer.

We describe herein a series of intricate trispirocyclic architectures that have been synthesized from readily available substrates through an operationally simple one-pot transformation under mild conditions.

An unprecedented gold(I)-catalyzed domino cyclization involving 2-ethynylbenzyl alcohol derivatives and heterocyclic α,β-unsaturated imines affords elaborated trispirocyclic cyclohexanes. This operationally simple protocol allows the one-pot generation of five bonds, three cycles, and four stereocentres in a short amount of time. Twenty substrates are successfully engaged, affording the desired products with good diastereoselectivity. The formation of these trispirocyclic compounds over other possible products has been rationalized by (DFT) density functional theory calculations.

The convergent total synthesis of a candidate diastereomer of amphirionin-5 was accomplished in 22 steps via the coupling of the C1-C16 enone segment and the C17-C28 aldehyde segment using Stetter reaction. The overall stereochemistry of amphirionin-5 was fully assigned, based on the comparison of spectroscopic and chiroptical data between the synthesized candidate diastereomer and the natural amphirionin-5.

Amphirionin-5, derived from dinoflagellates of the genus Amphidinium, exhibits a unique biological activity whereby trace amounts can lead to potent proliferation of osteoblasts, making it a promising candidate for regenerative therapy of bone and treatment of osteoporosis. However, the relative configuration of amphirionin-5 has only been partially determined. Herein, the total synthesis of amphirionin-5 is undertaken to establish its overall stereochemistry. Synthesized C16-C28 model with the proposed relative configuration of C19-C23 shows significant discrepancies between its NMR spectroscopic data around C19 and those of the corresponding substructures of the natural amphirionin-5, suggesting of necessity for reconsideration of the relative configuration of C19. Two further 19S-type C11-C28 models are synthesized, and detailed NMR analysis reveals that the 13C NMR of (19S,26R)-C11-C28 models show the best agreement with those in the corresponding substructure of the natural product; thus, the relative configurations from C19 to C26 of amphirionin-5 are proposed as 19S*, 20S*, 23S*, and 26R*. Coupling of the C1-C16 segment, synthesized from an optically active α-silyloxy pentanolide as a common intermediate, and the (19S,26R)-C17-C28 segment is achieved under intermolecular Stetter reaction conditions, enabling the convergent total synthesis of the candidate diastereomer of amphirionin-5. Ultimately, the overall stereochemistry of amphirionin-5 is fully assigned.