Zhao X, Qin T, Zhang L
… +6 more, Duan JJ, Zhang Z, Huang Y, Miao X, Li G, Wang T
J Am Chem Soc
· 2026 Jun · PMID 42366533
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Radical-mediated coupling reactions serve as powerful tools for chemical bond formation, leveraging the high reactivity of radical intermediates to achieve reactions inaccessible through traditional ionic pathways. Howev...Radical-mediated coupling reactions serve as powerful tools for chemical bond formation, leveraging the high reactivity of radical intermediates to achieve reactions inaccessible through traditional ionic pathways. However, achieving radical-mediated multisite coupling remains a significant challenge. Here, we report an on-surface synthesis strategy of delocalized π-radical-mediated multisite cooperative coupling for the highly selective synthesis of oxygen-doped nanographene. Initially, dehydrogenation of the hydroxyl group on the molecule generates a σ-radical, which simultaneously transforms into a delocalized π-radical due to orbital rehybridization. Subsequently, electron delocalization induced by the π-radical gives rise to the spin-density distribution along the entire periphery of the molecule, enabling multisite C-O and C-C coupling between two monomer units. Owing to the high regioselectivity imposed by steric hindrance between the carbonyl groups, high-yield (>95.6%) π-conjugated oxygen-doped nanographene is synthesized. Our work establishes a novel paradigm of cooperative multibond formation mediated by delocalized π-radicals, opening a promising avenue for the precise bottom-up synthesis of extended π-conjugated systems.
Coloma I, Giaconi N, Parmeggiani F
… +9 more, Buffeteau T, Pécastaings G, Herrero S, Hillard EA, Rosa P, Poggini L, Mannini M, Cortijo M, Gonidec M
J Am Chem Soc
· 2026 Jun · PMID 42364150
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The use of coordination compounds provides a promising strategy to unravel the factors governing chirality-induced spin selectivity (CISS), particularly the contribution of spin-orbit coupling (SOC) to its magnitude. Her...The use of coordination compounds provides a promising strategy to unravel the factors governing chirality-induced spin selectivity (CISS), particularly the contribution of spin-orbit coupling (SOC) to its magnitude. Here, we report the formation of self-assembled monolayers on gold substrates of a chiral paramagnetic Ru paddlewheel complex, [Ru(NCS){μ-()- or ()-pycsa}(μ-OAc)] (pycsa = -(pyridin-2-yl)-10-camphorsulfonamidate), denoted as ()- or ()-. The incorporation of camphor groups confers point chirality to the molecule and causes a slight twisting around the Ru unit, introducing also a helical chirality, as evidenced by single-crystal X-ray diffraction and dichroic electronic absorption. The complex features an axial ligand bearing a terminal sulfur atom that serves as a robust anchoring site to the metallic surface. The resulting SAMs are homogeneous, stable, and exhibit very reproducible electrical characteristics. Magnetic-conductive atomic force microscopy measurements on enantiopure Ni/Au- junctions reveal remarkable spin polarizations reaching values from 60 to 80%, which is particularly noteworthy considering the monolayer nature of the film and the modest helicity of the paddlewheel motif.
Nelson BR, Lochmaier EC, Kirkpatrick BE
… +8 more, Clark TR, Rynk JF, Fairbanks BD, Damrauer NH, Anseth KS, Appelhans LN, Fritzsching KJ, Bowman CN
J Am Chem Soc
· 2026 Jun · PMID 42363911
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Light-induced, initiatorless homopolymerization of 1,2-dithiolanes is widely attributed to radical propagation. However, several experimental observations, including copolymerization behavior and EPR measurements, are in...Light-induced, initiatorless homopolymerization of 1,2-dithiolanes is widely attributed to radical propagation. However, several experimental observations, including copolymerization behavior and EPR measurements, are inconsistent with this assignment. Here, this reaction is examined using in situ photoNMR, revealing first-order monomer consumption that is incompatible with a propagating radical mechanism. PhotoNMR further enables direct observation of a sulfonium intermediate attributed to a charge-transfer complex, corroborated through steady-state and transient absorption spectroscopy. Together, these data establish an activated-monomer-type polymerization, proceeding through a cationic rather than radical pathway. This same intermediate also enables controlled chain growth and is leveraged as a photoinitiator for cationic vinyl ether polymerization, extending the scope of dithiolane photochemistry beyond homopolymer formation and opening new opportunities for dithiolane-based photopolymerization strategies.
J Am Chem Soc
· 2026 Jun · PMID 42363908
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The performance regulation of polyolefin catalysts typically relies on complex ligand design and synthesis, which limits the rapid development of high-performance polyolefins. The heterogenization of homogeneous catalyst...The performance regulation of polyolefin catalysts typically relies on complex ligand design and synthesis, which limits the rapid development of high-performance polyolefins. The heterogenization of homogeneous catalysts presents a promising and industrially favorable approach to modulate and enhance the performance of transition-metal catalysts. This work introduces a general ionic cluster catalyst assembly (ICCA) strategy to achieve efficient heterogenization without the need for any catalyst supports. It transforms known hydroxyl-functionalized transition-metal catalysts into ionic cluster assemblies by a simple one-step reaction. The steric hindrance of the catalyst metal center can be easily tuned by varying the feed ratios for assembly, without requiring the synthesis of new catalysts. This ICCA strategy enables up to 20 times higher activity during ethylene homo- and copolymerization while significantly improving the molecular weight and mechanical properties of the resulting copolymers. Furthermore, the heterogeneous polymerization facilitated by this strategy demonstrates efficient heat transfer, lower system viscosity, and excellent fouling resistance during polymerization, indicating great potentials for scale-up polymerization. This work provides a general and efficient platform for tuning polyolefin catalyst performance.
Wang X, Li L, Yan N
… +19 more, Wang L, Millán R, Liu P, Chu Y, Zhou Y, Gao W, Xu J, Xu J, Yin W, Yuan B, Wu Z, Corma A, Xu S, Liu Z, Yan W, Guo P, Li J, Boronat M, Yu J
J Am Chem Soc
· 2026 Jun · PMID 42363894
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Ethylene/ethane separation underpins global polyolefin production but remains one of the most energy-intensive processes in the chemical industry because it relies on cryogenic distillation. Adsorptive separation using p...Ethylene/ethane separation underpins global polyolefin production but remains one of the most energy-intensive processes in the chemical industry because it relies on cryogenic distillation. Adsorptive separation using porous materials offers a promising alternative to conventional cryogenic distillation, potentially reducing energy consumption. However, the nearly identical physical properties of ethylene and ethane make the development of highly selective adsorbents exceptionally challenging. Herein, we report a lithium-exchanged silicoaluminophosphate zeolite (Li-SAPO-RHO) that achieves unprecedented ethylene/ethane separation by exploiting a cooperative gating mechanism in a flexible framework. A synergistic proton-Li gating effect at the flexible 8-ring apertures differentially modulates molecular transport barriers. Brønsted protons selectively facilitate ethylene diffusion, while Li cations create a trapdoor barrier that preferentially suppresses ethane transport, thereby amplifying kinetic discrimination. As a result, Li-SAPO-RHO exhibits excellent ethylene-selective adsorption performance, enabling the direct production of polymer-grade ethylene (>99.9%) from refinery dry gas with a productivity of 238.6 mmol/L. Structural analyses combined with ab initio molecular dynamics simulations reveal how proton-cation synergy amplifies kinetic discrimination between closely related molecules. These findings establish gate cooperativity as a powerful design principle for energy-efficient adsorptive separations. Due to its low cost, exceptional hydrothermal stability, and excellent cycling performance, Li-SAPO-RHO offers a promising platform for industrial light-olefin separations.
Liu YP, Guo SY, Ding ZY
… +4 more, Julaiti Y, Wang LY, Wu XF, Chen QA
J Am Chem Soc
· 2026 Jun · PMID 42363889
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Ring-expansion editing offers a transformative strategy that could reshape the landscape of ring scaffold construction in synthetic chemistry. The introduction of three-dimensionality ring into flat aromatic systems coul...Ring-expansion editing offers a transformative strategy that could reshape the landscape of ring scaffold construction in synthetic chemistry. The introduction of three-dimensionality ring into flat aromatic systems could afford important semisaturated fused heterocycles, yet efficient method to access sulfur-containing semisaturated fused pyridines (SSFPs) remains scarce. Herein, we report a pyridyl radical-driven catalytic strategy for the direct two-carbon ring expansion of readily available cyclic thioethers, providing efficient access to synthetically challenging SSFPs. This transformation is enabled by synergistic dual photoredox cycles that orchestrate a cascade of radical cross-coupling, C(sp)-S bond cleavage, and intramolecular cyclization between commercial bromopyridines and cyclic sulfides. The protocol demonstrates broad functional-group tolerance and substrate generality. Gram-scale synthesis and extensive downstream derivatizations, including late-stage semisaturation of pharmaceutical cores, highlight its synthetic utility. Mechanistic studies support a stepwise radical process involving discrete pyridyl and carbon-centered radical intermediates. This method offers a step-economical and modular alternative to conventional de novo synthesis for the rapid construction of complex, drug-like heterocyclic architectures.
J Am Chem Soc
· 2026 Jun · PMID 42363888
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Interrogation of the gas-liquid-solid triple-phase boundary (TPB) in membrane electrode assemblies (MEAs) operating at industrially relevant rates of CO electroreduction is highly desirable but remains challenging. Here,...Interrogation of the gas-liquid-solid triple-phase boundary (TPB) in membrane electrode assemblies (MEAs) operating at industrially relevant rates of CO electroreduction is highly desirable but remains challenging. Here, we develop an MEA-type surface-enhanced infrared absorption spectroscopy (SEIRAS) platform that enables selective detection of the buried catalyst-membrane interface at current densities up to 137 mA/cm on a Cu deposited-Au film substrate and up to 247 mA/cm using a sputtered Cu film. CO adsorption persists at high current densities and reaches near-saturation coverage under ambient pressure at the TPB. Deconvolution of the O-H stretching region reveals preferential depletion of cation-coordinated water, while CO reduction induces carbonate formation that reorganizes the hydrogen-bonding network toward a less reactive ice-like structure. These findings provide molecular-level evidence of adsorbate and hydration dynamics at the TPB and establish MEA-SEIRAS as a general approach for probing buried electrochemical interfaces.
J Am Chem Soc
· 2026 Jun · PMID 42363309
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Ring strain is a pervasive driving force in organic chemistry, enabling unique reaction pathways through the release of stored potential energy. Within the realm of palladium-norbornene cooperative catalysis (the Catella...Ring strain is a pervasive driving force in organic chemistry, enabling unique reaction pathways through the release of stored potential energy. Within the realm of palladium-norbornene cooperative catalysis (the Catellani reaction), norbornene (NBE) has long been regarded as an irreplaceable mediator, with its high ring strain considered indispensable for the catalytic cycle. In 2022, we reported a novel class of low-strained cooperative olefin ligands that challenge this structural paradigm. This system enables synthetically viable transformations inaccessible to traditional Pd-NBE catalysis, establishing itself as a robust complementary approach within the broader Catellani-type reaction regime of Pd-olefin catalysis. Herein, through a combined experimental and computational approach, we conducted a systematic comparative mechanistic study on representative Pd-NBE and Pd-olefin ligand systems. This work elucidates the role of ring strain in these reactions and identifies the critical factors governing the observed complementary reactivity. We demonstrate that ring strain is not a mandatory requirement for Catellani-type reactivity, and side-arm coordination is the key factor governing the divergent reactivity between Pd-NBE and Pd-olefin ligand systems. This work not only clarifies important mechanistic questions in Pd-olefin cooperative catalysis but also provides guiding principles for the future design of novel cooperative mediators and ligands.
J Am Chem Soc
· 2026 Jun · PMID 42361359
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Metal nanoparticles are core assets for modern technology for their widespread applications. Air|liquid interfaces, such as those present in microdroplets, are known to accelerate redox chemistry and enable unusual inter...Metal nanoparticles are core assets for modern technology for their widespread applications. Air|liquid interfaces, such as those present in microdroplets, are known to accelerate redox chemistry and enable unusual interfacial reactivity. Yet, many microdroplet studies rely on high-energy generation methods that complicate mechanistic attribution. We recently reported analogous behavior to microdroplet's interfacial activity in soap microfilms, where hydrogen peroxide formation occurred at the air|liquid interface without any external energy input. Here, we report the reduction of multiple transition metal ions and the formation of metal nanoparticles in ambient condition within the air|liquid interface of the soap microfilm, without adding any reducing agents or external energy input. Soap microfilms of aqueous solutions of different metal ion precursors of gold, silver, palladium, nickel, or cobalt were suspended by a simple commercial plastic bubble wand, collected, and then examined by high-resolution transmission electron microscopy, selected area electron diffraction, and energy-dispersive X-ray spectroscopy. In all cases, metal nanoparticles were formed, with gold exhibiting nanostar morphology, while the other metals displayed diverse morphologies. Control experiments performed in bulk solutions of identical composition showed no evidence of metal reduction, underscoring the unique reactivity of the air|liquid interface in the soap microfilm system. Furthermore, the resulting nanoparticle morphologies of the reduced metal ions correlated with the metal's thermodynamic energetics in the electrochemical series. Notably, for metal ions with negative standard reduction potential (vs SHE), the observed morphology depended sensitively on the microfilm's fate, whether the microfilm was kept intact or allowed to collapse into microdroplets. Intact microfilms favored compact isotropic particles, whereas microfilms that were allowed to collapse yielded anisotropic structures such as dendrites and nanowires. Our findings establish the soap microfilm system as a low-energy and no externally added reducing agent methodology for the formation of nanomaterials.
Kjaer LF, Ielasi FS, Winbolt T
… +6 more, Delaforge E, Tengo M, Nebl S, Bouvignies G, Palencia A, Jensen MR
J Am Chem Soc
· 2026 Jun · PMID 42361232
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Folding-upon-binding of intrinsically disordered proteins (IDPs) is governed by a complex interplay of kinetic and thermodynamic factors shaped by the structure and conformational dynamics of both binding partners. Alter...Folding-upon-binding of intrinsically disordered proteins (IDPs) is governed by a complex interplay of kinetic and thermodynamic factors shaped by the structure and conformational dynamics of both binding partners. Alternative splicing offers a natural way to remodel the conformational energy landscape of structured partners, yet how such biologically relevant changes influence the molecular recognition trajectories of interacting IDPs remains poorly understood. Here, using the small GTPase Rac1 and its oncogenic splice variant Rac1b as a model system, we integrate X-ray crystallography, isothermal titration calorimetry (ITC), and nuclear magnetic resonance (NMR) spectroscopy to investigate how the 19-residue insertion in Rac1b alters recognition of the disordered signaling effector POSH. We show that the insertion restricts POSH to partial folding-upon-binding and determine the crystal structure of the POSH-Rac1b complex at 1.77 Å resolution. The structure reveals that POSH stabilizes the otherwise dynamic switch regions of Rac1b in a signaling-competent conformation, while the insertion itself remains dynamic. NMR exchange experiments further delineate the molecular recognition trajectory of POSH upon binding to Rac1b, revealing a folding intermediate characterized by a 5.7-fold slower association rate and a 3-fold faster dissociation rate compared to Rac1. Together, these results demonstrate that the insertion, kinetically and entropically, destabilizes the effector-bound state of Rac1b, directly linking enhanced conformational dynamics to impaired downstream signaling. More broadly, our work illustrates how alternative splicing of folded proteins can reshape folding trajectories, binding kinetics, and thermodynamic landscapes of IDP-mediated interactions, thereby rewiring cellular signaling networks.
J Am Chem Soc
· 2026 Jun · PMID 42361045
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We present a quantum-dynamical framework for identifying structurally and functionally important residues in proteins based on continuous-time quantum walks (CTQWs) on weighted residue-interaction networks constructed fr...We present a quantum-dynamical framework for identifying structurally and functionally important residues in proteins based on continuous-time quantum walks (CTQWs) on weighted residue-interaction networks constructed from experimentally resolved structures. By mapping the weighted adjacency matrix to a Hamiltonian, residue importance emerges from the long-time averaged occupation probability, confirmed analytically through its spectral decomposition. Across a data set of 150 proteins spanning diverse structural and functional classes, CTQW centrality exhibits consistently strong agreement with classical eigenvector centrality in identifying central residues, while extending beyond it through incorporating signatures of quantum interference. Analyzing the time-averaged quantum transition matrix reveals consistently larger spectral gaps than the classical random-walk operator. Furthermore, biological relevance is confirmed through recovery of experimentally established functional residues in proteins kinase A and oxytocin. CTQW-derived centrality rankings are accessible on near-term intermediate-scale quantum hardware, as we demonstrate through a proof-of-principle implementation on IBM superconducting quantum hardware. These results establish continuous-time quantum walks as a computationally tractable framework for protein network analysis, that connects network theoretical treatments of protein structural biology to continuous-time quantum walk dynamics.
Huang JA, Fan H, Yuan W
… +8 more, Hua Y, Li H, Jiang TW, Jiang K, Wang J, Zhang J, Wei Z, Cai WB
J Am Chem Soc
· 2026 Jun · PMID 42360899
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The precise regulation of interfacial microenvironments by ionomers in membrane electrode assembly electrolyzers for CO reduction plays a pivotal role in determining their overall catalytic performance. Conventional anio...The precise regulation of interfacial microenvironments by ionomers in membrane electrode assembly electrolyzers for CO reduction plays a pivotal role in determining their overall catalytic performance. Conventional anion exchange ionomers possess rigid molecular backbones that limit their ability to dynamically respond to the interfacial electric field. Herein, we report that a rigid-flexible dual-piperidinium anion exchange ionomer (DQ) markedly enhances the CO-to-CO conversion on silver nanoparticles at industrial-level current densities. electrochemical impedance spectroscopy with distribution of relaxation times analysis, in conjunction with attenuated total reflection surface-enhanced infrared absorption spectroscopy, reveals that the DQ ionomer boosts ion conductivity at the triple-phase boundary by providing additional ion exchange sites and enriches local CO by disrupting the hydrogen-bond network of interfacial HO, thus promoting the apparent CO-to-CO electroreduction kinetics.
Sfreddo E, Durdevic A, Palone A
… +4 more, von Münchow T, Matera N, Mazzanti A, Melchiorre P
J Am Chem Soc
· 2026 Jun · PMID 42360297
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The Norrish-Yang photocyclization of aryl alkyl ketones is a classical photochemical transformation that proceeds through triplet 1,4-diradicals whose conformations govern the fate of the reaction. Directing the reactivi...The Norrish-Yang photocyclization of aryl alkyl ketones is a classical photochemical transformation that proceeds through triplet 1,4-diradicals whose conformations govern the fate of the reaction. Directing the reactivity of these diradicals is difficult because they can evolve through competing pathways, including cyclization and Norrish type II fragmentation. Achieving stereocontrol is even more challenging because radicals generated from enantiopure substrates are expected to undergo rapid configurational scrambling. Here we report a stereoretentive Norrish-Yang photocyclization of enantiopure aryl alkyl ketones enabled by hydrogen-bond-guided conformational control of the photogenerated 1,4-diradical. Hydrogen-bonding units encoded within the chiral substrate bias the reactive diradical manifold toward cyclization while suppressing fragmentation and stereochemical erosion. The reaction affords highly enantioenriched spirocyclobutanol-containing amines and related cyclobutanols bearing two stereocenters, with high enantiospecificity across a range of amino-acid-derived substrates.
Senzaki T, Yasukawa T, Yamashita Y
… +6 more, Maki T, Yamamoto M, Yoshida T, Oshiro K, Gao M, Kobayashi S
J Am Chem Soc
· 2026 Jun · PMID 42360121
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Single-atom catalysts have emerged as powerful platforms for selective hydrogenation reactions owing to their well-regulated active sites; however, their unique reactivity in cascade hydrogenation processes remains relat...Single-atom catalysts have emerged as powerful platforms for selective hydrogenation reactions owing to their well-regulated active sites; however, their unique reactivity in cascade hydrogenation processes remains relatively unexplored. Herein, we report that a single-atom platinum catalyst supported on N,P-doped carbon efficiently catalyzes the cascade hydrogenative coupling of nitro compounds and aldehydes, leading to the highly selective synthesis of nitrones. This catalytic system enables the facile production of 40 diverse nitrones, including those derived from aromatic and aliphatic substrates, as well as important intermediates of bioactive compounds. In sharp contrast to nanoparticle catalysts that promote over-reduction, this Pt single-atom platform exhibits broad functional-group tolerance, accommodating reducible C═C and C═O bonds and aryl halides. Furthermore, the catalyst demonstrates robust durability in a continuous-flow system, providing an atom-economical and sustainable methodology for nitrone synthesis.
Das OR, Alalq I, Crouch J
… +4 more, Zornes A, Crossley S, Wang B, White JL
J Am Chem Soc
· 2026 Jun · PMID 42360109
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Zeolite Y catalysts contain Brønsted acid sites in accessible large pores, known as supercages, and in sterically inaccessible small pores within sodalite cages. Access to acid sites within sodalite units is precluded du...Zeolite Y catalysts contain Brønsted acid sites in accessible large pores, known as supercages, and in sterically inaccessible small pores within sodalite cages. Access to acid sites within sodalite units is precluded due to their 0.26 nm cage windows, which are smaller than the critical diameters of relevant hydrocarbons. By preparing a series of HY catalysts with different acid site densities, including for the first time reported those with theoretical maximum acid site density, the number of acid sites in the inaccessible sodalite cages is shown to be a dominant factor in reactivity for catalysts in which the structural integrity of the sodalite unit is preserved. Using a combination of catalyst preparation, spectroscopy, isotopic exchange measurements with bulky hydrocarbons, and high-temperature isooctane cracking experiments on catalysts with fixed supercage proton amounts but varying sodalite proton concentrations, the dominant contribution of sodalite cage acid sites is quantified. DFT calculations suggest that a plausible mechanism involves framework flexibility in the form of site exchange via rotation of sodalite protons into supercages. In addition to revealing that commonly used acid site density measurements and turnover frequency calculations may exclude contributions from important sites, these data demonstrate that BASs in intact sodalite cages can define and control catalyst reactivity in HY catalysts. Large increases in catalyst activity are obtained by exchanging La cations into sodalite cages with maximum acid site densities. These findings extend beyond HY catalysts, as they imply that other zeolite catalysts with sterically occluded acid sites may be tuned for improved performance.
J Am Chem Soc
· 2026 Jun · PMID 42360066
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Understanding the atomic structure, speciation, and reactivity of surface sites is critical for establishing structure-activity relationships in heterogeneous catalysis. A longstanding objective in this field is the simu...Understanding the atomic structure, speciation, and reactivity of surface sites is critical for establishing structure-activity relationships in heterogeneous catalysis. A longstanding objective in this field is the simultaneous identification of Brønsted acid sites (BASs) and the quantification of their acidity. Although BASs often govern the overall reactivity of catalysts and specific support effects such as bifunctionality, achieving this objective has remained a grand challenge. In this work, we selectively tag reactive surface functionalities on materials, such as -OH groups spanning a wide range of acidity, using an organosilver(I) compound that incorporates Ag and P reporter nuclei at natural abundance. This P-Ag surface tag, which can be visualized by transmission electron microscopy (TEM) when applicable, provides dual NMR probes, enabling a high-resolution characterization of BASs by solid-state nuclear magnetic resonance (SSNMR) spectroscopy. Leveraging Dynamic Nuclear Polarization Surface Enhanced NMR spectroscopy (DNP-SENS), 2D P-{Ag} -correlated NMR spectroscopy enables the detection and resolution of different surface functionalities (e.g., reactive -OH and -NH groups) and their speciation (e.g., terminal O vs bridging O sites) across various levels of surface complexity. Rationalizing the complementary NMR signatures of P-Ag tags using Density Functional Theory (DFT) calculations and constructing a 2D map enables the precise evaluation of surface acidity across diverse sites and materials. The simultaneous identification of surface structures and quantitative assessment of their properties or reactivities advance the molecular-level understanding of the surface sites and chemistry in functional materials, paving the way for rational design, in heterogeneous catalysis.
Baker CF, Davis M, Seed JA
… +6 more, Sakho A, Bonham KL, Wooles AJ, Adams RW, Lee D, Liddle ST
J Am Chem Soc
· 2026 Jun · PMID 42360052
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Diphosphonioalkylidene ligands have been central to developing f-element M═CR double bond chemistry, but their wide range of C C NMR isotropic chemical shift (δ) values has rendered their nature open to qualitative debat...Diphosphonioalkylidene ligands have been central to developing f-element M═CR double bond chemistry, but their wide range of C C NMR isotropic chemical shift (δ) values has rendered their nature open to qualitative debate. Here, we report the use of C and O NMR spectroscopies to quantify the chemical shift anisotropies (CSAs) of two diphosphonioalkylidene complexes─[U(BIPM)(O)(Cl)] (, , 134, 10047-10054; BIPM = {C(PPhNSiMe)}) and [Y(BIPM)(I)(THF)] (; , 28, 6771-6776)─that exhibit disparate solution/solid-state C C δ values (386.2/401.9 and 61.0/54.9 ppm, respectively) and for a highly deshielded solution oxo O NMR δ (1333.6 ppm). CSA analysis reveals encoded chemical shift tensor (CST) signatures for the U═C and U≡O bonds of due to strong σ ↔ π* and π ↔ σ* magnetic shielding (σ) couplings; the U═C bond exhibits C δ and span (Ω) values that are both ∼ 50 ppm larger than any alkylidene complex, and the U≡O O δ is deshielded >200 ppm compared to uranyl O NMR data. CSA analysis confirms dominant 5f-orbital bonding and is consistent with an inverse--influence in the C═U≡O linkage of . By contrast, the C NMR data for exhibit signatures of Y═C double bonding tensioned with C═P ylidene contributions. For the M═CR bonds, we find that the C δ (σ), δ (σ), Ω, and the paramagnetic contribution to the shielding (σ) CSTs correlate strongly to bond order for a range of transition metals, rare earths, and actinides. This work demonstrates that CSA analysis is a powerful method for probing actinide chemical bonding, and it brackets the spectroscopic and bonding variance of diamagnetic diphosphonioalkylidene complexes.
Nakazawa M, Yamada T, Tang Y
… +2 more, Zeng X, Ichikawa T
J Am Chem Soc
· 2026 Jun · PMID 42360044
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The Grotthuss mechanism is a proton conduction mechanism where proton transports through the hydrogen-bonding network of water molecules. This mechanism enables high ionic conductivity, which is well utilized in nature a...The Grotthuss mechanism is a proton conduction mechanism where proton transports through the hydrogen-bonding network of water molecules. This mechanism enables high ionic conductivity, which is well utilized in nature and some proton-active artificial devices. Since this mechanism requires cleavage and reformation of hydrogen-bonding networks, its activation energy () is generally in the range of 10-15 kJ mol. Aiming to create a new mechanism beyond the Grotthuss mechanism, we focused on the surface proton hopping conduction (SPHC) mechanism, where a proton hops between neighboring sulfonate groups via bound water molecules. Generally, the SPHC mechanism requires a large . Our idea is that constructing densely aligned sulfonate groups should lead to small (≤10 kJ mol) and high proton transport efficiency. To realize high-density alignment of sulfonate groups with an average distance of ca. 5 Å, we employed the self-assembly of a liquid-crystalline (LC) discotic molecule . self-assembled into a hexagonal columnar LC structure in the presence of an appropriate amount of water. The /HO mixtures showed a maximum proton conductivity of 3.5 × 10 S cm at 30 °C and a small of 6.0 kJ mol when the water content = 53 wt %. We confirmed that extremely fast proton conduction and a small were achieved through only bound water. The dynamics of this bound water were quantitatively evaluated by QENS measurement. These results led us to conclude that the high proton conductivity in the columnar LC materials is primarily based on an extremely activated SPHC mechanism.
Wu JH, Ji CA, Wang N
… +8 more, Bi QQ, Zhao Y, Huang HN, Tan S, Miao LP, Fu XB, Lu XZ, Zhang W
J Am Chem Soc
· 2026 Jun · PMID 42359960
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Rashba-Dresselhaus (RD) spin splitting provides a crucial physical basis for realizing various advanced spintronic applications. Nevertheless, rationally regulating the RD splitting coefficient () continues to be a diffi...Rashba-Dresselhaus (RD) spin splitting provides a crucial physical basis for realizing various advanced spintronic applications. Nevertheless, rationally regulating the RD splitting coefficient () continues to be a difficult task owing to the still unclear structure-property relationship. In this work, we propose a molecular dipole engineering, the core of which involves introducing halogen atoms with different electronegativities into organic cations, aiming to design and synthesize two-dimensional (2D) ferroelectric semiconductors with strong RD spin splitting. By substituting the organic spacer cations in the parent compound (PMA)PbCl (PMA = benzylammonium), we obtained two new 2D ferroelectric semiconductors, namely, (2F4ClPMA)PbCl (2F4ClPMA = 2-fluoro-4-chlorobenzylammonium) and (2F4BrPMA)PbCl (2F4BrPMA = 2-fluoro-4-bromobenzylammonium). Both variants exhibit significantly enhanced RD splitting coefficients. In particular, (2F4ClPMA)PbCl possesses a large value of 1.878 eV·Å and a persistent spin texture region, which helps amplify its circular photogalvanic effect (CPGE). Through the spin-selective optical transition rule, the effect can enable the differentiation of carriers excited by circularly polarized light (CPL) in momentum space. A photodetector fabricated based on a (2F4ClPMA)PbCl single crystal shows a high asymmetry factor of 0.53 under excitation by UV CPL at 325 nm. This work not only confirms the effectiveness of the molecular dipole engineering in tuning RD spin splitting, but also lays an important material foundation for the development of novel low-power, high-sensitivity spin-optoelectronic devices.