Recent ucb_chemistry items

CP26 is not involved in qE- or qZ-type non-photochemical quenching in Arabidopsis

Fri, 19 Jun 2026 00:00:00 +0000

CP26 is a monomeric minor light-harvesting complex of Photosystem II (LHCII) protein located at the interface between LHCII trimers and the PSII core in thylakoid membranes. Previous studies have proposed CP26 plays a role in non-photochemical quenching (NPQ) in addition to light harvesting. Here, we utilized biophysical and pharmacological approaches to investigate this role using single- and higher-order Arabidopsis (Arabidopsis thaliana) cp26 mutants, examining its relationship to known NPQ regulators (Photosystem II subunit S, PsbS, violaxanthin de-epoxidase, VDE, and the pH gradient across the thylakoid membrane). cp26 mutants showed significantly reduced maximum PSII quantum efficiencies (Fv/Fm) in darkness, indicating a constitutively quenched state further confirmed by fluorescence lifetime measurements. Destabilized PSII-LHCII supercomplexes observed in native gel electrophoresis and tighter PSII supercomplex packing were potential causes, with no other antenna proteins...

Understanding the Cathode Electrochemistry of Humidified Solid‐State Lithium‐Oxygen Batteries

Thu, 18 Jun 2026 00:00:00 +0000

Abstract Lithium‐oxygen batteries (LOBs) possess a high theoretical energy density, making them potential candidates for next‐generation energy storage. However, challenges such as reactive oxygen species‐induced component degradation hinder their practical use. Inorganic solid‐state electrolytes offer an alternative to degradation‐prone aprotic electrolytes, while also protecting lithium anodes from potential atmospheric reactants. This study explores the cathode electrochemistry of solid‐state LOBs using humidified oxygen, which forms an aqueous catholyte during initial cycling, thereby improving cathode‐electrolyte contact. To quantitatively analyze the cathode electrochemistry, a ‘Humidity‐Incorporated’ Differential Electrochemical Gas Monitoring System (HiDEMS) is developed to control humidity and monitor gas consumption and evolution in real time. When studying a Li‐O 2 cell that employs a NASICON‐type Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) solid electrolyte and a porous...

Consistent inclusion of triple substitutions within a coupled cluster based static quantum embedding theory

Thu, 18 Jun 2026 00:00:00 +0000

We have previously proposed the MPCC static embedding framework for quantum chemistry that self-consistently couples a high-level coupled cluster (CC) treatment of the fragment (active region) with a lower level, Møller-Plesset perturbation treatment of the environment. Our initial implementation was limited to single and double (SD) substitutions, with CCSD for the fragment and first-order perturbative SD amplitudes for the environment. Here, we extend the MPCC embedding treatment to triple substitutions, which is essential for achieving chemical accuracy in energy differences. To this end, we employ a CCSDT solver for the fragment subsystem. For the environment subsystem, we construct a perturbative estimate of the triples amplitudes, explicitly accounting for feedback from all fragment amplitudes. The resulting approach is denoted MPCCSDT(pt). We further introduce a more complete formulation in which feedback from the environment amplitudes to the fragment amplitudes is...

Si–Cl Bond Activations at Ni(0) to Give Bimetallic Ni(I) μ1,2-Cl–SiR1R2 Complexes that Undergo Selective Hydrogenolyses to R1R2SiH2 Dihydrosilanes

Thu, 18 Jun 2026 00:00:00 +0000

Chlorosilanes are cheap and abundant raw materials as crucial building blocks in silicon chemistry, yet the metal-mediated activation and functionalization of Si–Cl bonds typically require precious metal sources due to their thermodynamic inertness. Herein, we report the stoichiometric, facile activation, and hydrogenolysis of chlorosilanes mediated by a series of low-valent NHC–Ni (NHC = N-heterocyclic carbene) complexes. Treatment of a Ni(0) complex (IPr)Ni(η6-toluene) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene) with chlorosilanes (R1R2SiCl2, R1 = Cl, R2 = Cl, Me, Ph, or R1 = R2 = Me, Et, Ph, 4-MePh) rapidly afforded di-Ni(I) complexes with a bridging silyl ligand ([(IPr)Ni]2(μ-SiR1R2Cl)(μ-Cl), 1 R1,R2 ) in high yields. Use of a bulkier chlorosilane, Ph2SiCl2, allowed the isolation of the mono-Ni(II) silyl complex (IPr)Ni(SiPh2Cl)Cl (2 Ph ) as an intermediate generated via Si–Cl oxidative addition, which underwent comproportionation with (IPr)Ni(η6-toluene) to...

Uranyl Tris(benzoate) Photocatalysts for Site-Selective Hydrocarbon Functionalization.

Tue, 16 Jun 2026 00:00:00 +0000

The uranyl dication ([UO₂]²⁺) is a highly active photocatalyst for the functionalization of inert C_sp3-H bonds by direct hydrogen atom abstraction (HAA). However, photocatalysis by the uranyl ion remains underexplored. Most reports are limited to reactions catalyzed by simple uranyl salts, such as uranyl nitrate [UO₂(NO₃)₂·6H₂O] (U^NO3). We report a set of uranyl tris(benzoate) complexes 1-R containing strongly coordinating and tunable equatorial ligands that resist photodamage and control access to the oxo groups. These catalyst variants with appropriate aryl substituents undergo catalytic reactions at C-H bonds by HAA. The selectivity and reactivity of this step depend on the ligand framework and are distinct from that of U^NO3 or other photoactive oxo complexes, such as decatungstate, that lack ancillary ligands. Finally, consistent with the strong,...

Beyond the Pre‐Equilibrium Approximation: Consequences of Elementary Step (Ir)reversibility on the Mechanistic Interpretation of Tafel Slope

Tue, 16 Jun 2026 00:00:00 +0000

The relationship between electrochemical potential and reaction rate-or Tafel slope-is fundamental to the study of multi-step charge transfer reactions. However, despite its importance and ubiquitous use, Tafel slope is seldom interpreted outside of "cardinal" values. The mechanistic interpretation of cardinal Tafel slopes is predicated on the pre-equilibrium approximation (PEA): that the path between the (catalyst) resting state and rate-determining step is in equilibrium. This stringent approximation severely limits opportunities to elicit mechanistic information from electrochemical processes. In this Scientific Perspective, we broaden the existing framework for mechanistic interpretation of Tafel slope through a simple, universal equation that generally describes Tafel slope in terms of elementary-step symmetry factors and approach-to-equilibrium (i.e., approach to PEA accuracy). The predictiveness and mechanistic utility of these theoretical developments are showcased through...

Field-driven ion pairing dynamics in concentrated electrolytes

Thu, 11 Jun 2026 00:00:00 +0000

We investigate ion pairing dynamics in electrolytes driven far from equilibrium using molecular simulations and nonequilibrium rate theory. Focusing on 0.5M LiPF6 in water and acetonitrile under uniform electric fields, we compute transition path theory observables, including reactive fluxes and mean first-passage times of ion pairing. Moreover, we introduce a dynamical proxy of free-ion population, where its field-induced change is strongly correlated with the nonlinear enhancement of conductivity, yielding an increase of 40% at 50 mV/Å in acetonitrile, compared to that of less than 10% in aqueous electrolytes. Further kinetic analysis elucidates that Onsager's classical theory substantially overestimates field-induced enhancement of ion pair dissociation in molecular electrolytes. This discrepancy arises from solvent-mediated dynamical pathways and field-induced dielectric decrement that suppress ion pair dissociation within explicit solvents, highlighting that a faithful...

Solvent effects on triplet yields in BODIPY-based photosensitizers

Thu, 11 Jun 2026 00:00:00 +0000

We employ molecular dynamics simulations and quantum rate theories to elucidate the complex condensed-phase dynamics underpinning triplet-state formation in organic photosensitizers. Using models informed by first-principles calculations complete with a molecular representation of solvents of different polarities, we elucidate the interplay of the internal and environmental interactions underlying triplet yield. We find that triplet yields depend sensitively on the dielectric stabilization of the charge transfer intermediate that facilitates a transition into the triplet manifold. Our results illustrate the importance of molecularly detailed models in understanding the excited-state internal charge-transfer dynamics of photochemically relevant organic molecules.

Nanocrystal Geometry Governs Phase Transformation Pathways in Palladium Hydride.

Wed, 10 Jun 2026 00:00:00 +0000

Pathways and structural dynamics of phase transformations impact performance of materials in energy and information storage technologies. Palladium hydride (PdH_x) nanocrystals are an ideal model system for studying solute-induced phase transformations, where elastic energy from lattice mismatch between α-PdH_x and β-PdH_x phases is often considered a key to determining the transformation pathways. α/β-PdH_x interfacial elastic energy is affected by the confined geometry of a nanocrystal. However, how nanocrystal geometry influences phase transformation pathways is largely unknown. Using in situ liquid phase transmission electron microscopy, we directly visualize hydrogenation in Pd nanocrystals with two geometries, a nanocube and a hexagonal nanoplate. Both follow similar sequences of an initially curved nucleus, interface flattening, and reverse-stage nucleation; however, their evolving α/β-PdH_x...

How Does Water Dissociation Work in Bipolar Membranes?

Wed, 10 Jun 2026 00:00:00 +0000

Bipolar membranes (BPMs) create counteracting spatial gradients of pH and electrostatic potential in electrochemical systems, enabling applications in pH regulation, electrocatalysis, and separations. At the polarized junction of a BPM the water dissociation (WD, 2H₂O ⇌ H₃O⁺ + OH^-) reaction can be driven, but it remains poorly understood. In this Perspective, we integrate molecular insights from bulk-water autoionization and the associated field effects with continuum descriptions of BPM electrostatics and experimental WD kinetic analyses to describe possible mechanisms of voltage-driven WD. Pristine BPM junctions highlight both the limits of primarily electric-field-driven WD and the practical challenges of junction stability at extreme reverse bias. Introducing heterogeneous catalyst layers, commonly metal oxides and graphene oxides, accelerates WD by orders of magnitude through hypothesized coupled effects in which surface acid-base...

Polyolefin blends with co-continuous architectures enabled by dynamic covalent crosslinking

Wed, 10 Jun 2026 00:00:00 +0000

Blending polymers produces brittle materials due to macrophase separation and poor interfacial adhesion, which is exemplified by mixtures of polyolefins. This presents a formidable challenge for the mechanical recycling of mixed plastic waste. Here, we demonstrate that dynamic covalent crosslinking of immiscible polyolefin blends creates macrophase separated co-continuous architectures, yet they display excellent mechanical properties, which challenges the conventional wisdom regarding morphology-property relationships in polymer blend compatibilization. We find that the position and orientation of dynamic crosslinks and their influence on crystallinity are key to understanding the structure-morphology-property relationships. In particular, high-resolution microscopy imaging reveals alignment of crystallite planes with strong orientational preference, particularly at polymer-polymer interfaces, which contribute to material performance. We further demonstrate that changes in crosslinker...

A Lens into the Cu Nanograin by In Situ Vibrational Spectroscopy

Wed, 10 Jun 2026 00:00:00 +0000

Cu-based catalysts are uniquely capable of C-C coupling during electrochemical CO₂ reduction (CO₂R), yet further mechanistic understanding remains hampered by the lack of spectroscopically resolved descriptors that demonstrate how surface adsorbates emerge and evolve within their catalytic environment. Here, we correlate in situ surface-enhanced Raman spectroscopy (SERS) and surface-enhanced infrared absorption spectroscopy (SEIRAS) to resolve the potential-dependent dynamics during CO₂R on Cu nanograin catalysts. By building on previous benchmarking of low overpotential performance and nanograin structural evolution, we offer a diagnostic framework linking vibrational signatures to catalytic function, unveiling which species appear, persist, and turnover as the electrified surface and interfacial environment evolve under bias. The onset of linear CO is marked below -0.45 V, coincident with persistent adsorbed *OH/*O domains beyond the CO₂R...

An International Laboratory Comparison Study on Approximating the Enthalpy of Adsorption via the Clausius‐Clapeyron Approach

Mon, 8 Jun 2026 00:00:00 +0000

Materials-based gas capture and storage is an increasingly important area of research. Robust and accurate determination of material properties is required for judicial selection of materials for specific applications and for engineering materials-based systems at scale. One key property is the strength of the adsorbate-adsorbent interaction often quantified via the isosteric enthalpy of adsorption. The heat of adsorption can be measured directly through calorimetry; however, a more widely used approach is to apply the Clausius-Clapeyron (CC) equation to adsorption isotherms collected at different temperatures. While this approach appears to be straightforward, there exist multiple variants in the application of the methodologies employed. This raises the question on how these variations may or may not affect the determined results. Presented here is a discussion of the most common methodologies and a comparison of indirect determinations (via CC) of the isosteric enthalpy of...

Reducing Flavin and Ubiquinone Headgroups with Silicon Nanowire Photocathodes

Fri, 5 Jun 2026 00:00:00 +0000

Photosynthetic biohybridsa structure composed of semiconducting electrodes and carbon dioxide-fixing autotrophs which can be energized by the electrodeoffer a promising platform for selective CO2 reduction. However, studying the charge-transfer mechanisms from the semiconductor to the cell proves challenging due to a variety of simultaneous processes. Therefore, to deconvolute the system to understand photoelectrochemical performance, we employ model systems composed of a subset of the electron-transfer pathway. Here, we photoelectrochemically reduced ubiquinone-0 (UQ0) and riboflavin (Rf) (the head groups of ubiquinone-8/10 and flavin mononucleotide/flavin adenine dinucleotide) using Pt-decorated n+p-silicon nanowires, a robust catalytic architecture. Under irradiation with 100 mW cm–2 red light (740 nm), UQ0 and Rf were reduced with onset potentials of 0.876 V vs the reversible hydrogen electrode (VRHE) and 0.691 VRHE, respectively. In addition, UQ0 achieved a maximum Faradaic...

Dissecting the contributions to non-photochemical quenching in a land plant under fluctuating light

Wed, 3 Jun 2026 00:00:00 +0000

Photosynthetic organisms have evolved multiple non-photochemical quenching (NPQ) processes, providing photoprotection by safely dissipating excess excitation energy. These processes involve various molecular players functioning on overlapping timescales from seconds to days, making it challenging to isolate and quantify their individual kinetics. In this study, we perform whole-leaf chlorophyll fluorescence lifetime and xanthophyll concentration measurements on wild-type and various newly characterized NPQ mutants of Nicotiana benthamiana, a vascular land plant. Based on these measurements, we construct a fluorescence lifetime-based quantitative kinetic model that disentangles individual photoprotection components and, when integrated additively, accurately predicts wild-type and mutant NPQ behaviors under various light-dark regimes. Additionally, the model quantifies the per-molecule quenching effectiveness of various xanthophylls and the contributions of six quenching components...

Plutonium(III) versus uranium(III) and samarium(III) in small molecule activation chemistry

Fri, 29 May 2026 00:00:00 +0000

We report the PuIII complex, [PuIII(CpMe4)3] (1-Pu), and demonstrate its differences in small molecule reactivity compared to the UIII and SmIII analogs, [UIII(CpMe4)3] (1-U) and [SmIII(CpMe4)3] (1-Sm), respectively. 1-Pu reductively cleaves the small molecule (PhS)2, affording a PuIII complex, [{PuIII(CpMe4)2}2(μ-SPh)2] (2-Pu), while retaining the PuIII center and eliminating (CpMe4)2 as a by-product, a fingerprint of a sterically induced reduction (SIR) reaction. Sm is often used as a surrogate for Pu, but the analogous [SmIII(CpMe4)3], (1-Sm), is unreactive. The (PhS)2 cleavage by 1-U proceeds solely via a metal-based oxidation (i.e., UIII → UIV), to form [UIV(CpMe4)3(SPh)] (3-U). Only 1-U reacts with (PhHN)2, affording the reductive cleavage product, [UIV(CpMe4)3(NHPh)] (4-U). The difference in reactivity of 1-Pu compared to complexes 1-Sm and 1-U was unexpected, and since SIR chemistry can enable complexes to participate in otherwise impossible reductive transformation of...

Tuneable electronic coupling in linked bis(cubane) cobalt-oxo clusters

Wed, 27 May 2026 00:00:00 +0000

A family of cobalt-oxo bis(cubane) complexes wherein each subunit is derived from the Co₄O₄ cubane, a known water oxidation catalyst, was synthesized. Both 4,4'-bipyrdine and pyrazine were demonstrated to serve as viable bridging ligands. Through an analysis of their half-wave splitting potentials, it was determined that pyrazine-bridged bis(cubane)s exhibit inter-cubane electronic coupling, and that this coupling may be tuned through ligand substitution. Electrostatic contributions to the half-wave splitting potentials were evaluated and found to result in "non-conformist" behavior related to the ion-pairing ability of the electrolytes.

One-Body Properties and Their Perturbative Accuracy with Aufbau Suppressed Coupled Cluster Theory

Wed, 27 May 2026 00:00:00 +0000

We derived and implemented the calculation of the one-body reduced density matrix for Aufbau suppressed coupled cluster theory, from which excited state natural orbitals and one-body properties, like atomic populations and dipole moments, are obtained. We utilized the natural orbitals to refine the ASCC solution for simple valence and Rydberg systems, exploring the process of repeatedly solving the ASCC equations in successive natural orbital bases to achieve independence from the starting molecular orbitals. For dipole moments in small molecules where high-level comparison data is available, we find that the accuracy of ASCC essentially matches that of linear response and equation-of-motion coupled cluster as long as care is taken to preserve the response's perturbative completeness.

Correction: Sustainable bioproduction of the blue pigment indigoidine: Expanding the range of heterologous products in R. toruloides to include non-ribosomal peptides

Mon, 25 May 2026 00:00:00 +0000

Correction for ‘Sustainable bioproduction of the blue pigment indigoidine: Expanding the range of heterologous products in R. toruloides to include non-ribosomal peptides’ by Maren Wehrs et al. , Green Chem. , 2019, 21 , 3394–3406.

Colloidal stability and aggregation of polyethylene (PE) nanoplastics under UV weathering and PFOA contamination

Fri, 22 May 2026 00:00:00 +0000

The colloidal stability of polyethylene nanoplastics (PE NPs) impacts their environmental fate. UV weathering and pollutant adsorption modify the surface of nanoparticles, alter particle-particle interactions and, in turn, modulate their colloidal stability. This study reports on the colloidal stability of 200 nm PE NPs as a function of salt concentration and surface treatment. Colloidal stability is determined for the as made particles, after UV weathering, and in the presence of perfluorooctanic acid (PFOA). Aggregation kinetics is determined using dynamic light scattering and zeta potentials. The surface properties of the PE NPs are characterized using FT-IR spectroscopy, tensiometry, and adhesion measurements. Pristine PE NPs are colloidally stable in dispersions below ∼0.1 mol L^-1, but rapidly aggregate at higher salt concentrations. Environmental modifications have contrasting effects on PE NP stability. The presence of PFOA does not significantly impact the overall...

Stress-aided thermal activation of crack propagation in multidentate hydrogen bonding adhesives.

Fri, 22 May 2026 00:00:00 +0000

Adhesives containing multidentate hydrogen bonding moieties are gaining prominence for their ability to adhere strongly underwater. Previous studies attributed their remarkable underwater adhesion to the multiple adjacent attachment points within a moiety stabilizing the bond, enabling cooperative hydrogen bonding. However, as adhesion involves multiple coupled phenomena, isolating the contribution of individual bonds to the adhesive strength remains challenging. Here we investigate the relationship between peeling velocity and adhesion over a range of temperatures to estimate the activation energy of the chemical bonds that fracture at the adhesive interface. We utilize a model epoxy modified by the addition of tridentate hydrogen bonding moieties (DGEBA-Tris). We report on the effect of curing, debonding temperature, and crack velocity on the adhesive strength at the DGEBA-Tris/mica interface. Adhesion is measured using self-arrested crack propagation to probe the threshold...

Spin Polarization from Circularly Polarized Light Induced Charge Transfer

Fri, 15 May 2026 00:00:00 +0000

We show how a spin polarization can be generated through the photoinduced electron transfer of an achiral donor-acceptor complex following chiral light excitation. In particular, we illustrate the basic energetic and symmetry requirements for chirality induced spin selectivity where the chirality emerges from the electronic degrees of freedom following excitation with circularly polarized light. We study this effect in a simple model of a metalloporphyrin complex with an axial acceptor ligand using quantum mechanical rate theories and numerical simulations. We find that the spin polarization emerges due to the selective excitation of a ring current within the porphryin, breaking the degeneracy of the two degenerate spin states. The resultant spin polarization increases with the spin orbit coupling between the metal in the porphyrin and the axial ligand, and is transient, with a lifetime dependent on the rate of dephasing from the Jahn-Teller distortion mode. This proposed effect...

A photochargeable semiconductor for highly efficient dehydrogenative coupling of amines

Fri, 15 May 2026 00:00:00 +0000

The development of materials with high photocatalytic efficiency is essential for sustainable chemical transformations. Here we introduce photochargeable zinc indium sulfide nanocrystals with notable charge storage capacity, enabling highly efficient photocatalytic dehydrogenative coupling of amines. Combined with a nickel cocatalyst, the nanocrystals deliver diamines and hydrogen at rates exceeding 120 mmol per gram of photocatalyst per hour, with > 95% selectivity and an apparent quantum efficiency of up to 39.4% under ambient conditions. The system exhibits excellent scalability, demonstrated by a reaction on a 20-g scale, and broad versatility in promoting amino acid ester coupling and polymerization reactions with concurrent hydrogen evolution. Mechanistic studies attribute the photocharging capability of zinc indium sulfide nanocrystals to in situ-generated trap states such as sulfur vacancies, which extend hydrogen production into the dark catalytic cycle and enhance...

Leveraging a synthetic biology approach to enhance BCG-mediated expansion of Vγ9Vδ2 T cells

Thu, 14 May 2026 00:00:00 +0000

There is an urgent need to develop a more efficacious anti-tuberculosis vaccine as the current live-attenuated vaccine strain BCG fails to prevent pulmonary infection in adults. In this study, we leverage a synthetic biology approach to engineer BCG to produce more (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), an intermediate of bacterial-but not host-isoprenoid biosynthesis via the methylerythritol phosphate (MEP) pathway. HMBPP strongly activates and expands Vγ9Vδ2 T cells, which are unique to higher-order primates and protect against Mycobacterium tuberculosis infection. BCG has been engineered to produce specific ligands and antigens to some success; in contrast, our strategy exploits a self-nonself recognition mechanism in the host via HMBPP sensing, which has not been attempted before. To inform the design of our recombinant strains, we performed synteny analyses of >63 mycobacterial species and found that isoprenoid biosynthetic genes are not operonic across...

What is quantum biology?

Thu, 14 May 2026 00:00:00 +0000

Quantum biology is the field at the intersection of quantum-related physics and the biology of living systems. The goal of the field is to determine if quantum phenomena underpin biological function at the macroscale. Such results, supported by compelling experimental evidence, will be important because they will show how quantum effects can have functional relevance, even in very complex and nominally classical systems. Here, we attempt to define the scope of quantum biology with a forward-facing view to help focus the research agenda. To that end, we propose open questions fundamental to consolidating the field of quantum biology. These open questions highlight the importance of developing suitable probes at the quantum scale, the possibility that classical biological machinery might simply mimic quantum systems, and of elucidating the ways quantum function can be amplified to the macroscale.

Out-of-time-order correlators bridge classical transport and quantum dynamics

Thu, 14 May 2026 00:00:00 +0000

The out-of-time-order correlator (OTOC) has emerged as a central tool for quantifying decoherence across wide-ranging physical platforms. Here, we demonstrate its direct measurement in a classical ensemble using nuclear magnetic resonance with a modulated gradient spin echo sequence and extend the method into a multidimensional correlation to track exchange phenomena. Position is encoded through magnetic field gradients and momentum through the velocity autocorrelation function, enabling experimental access to OTOCs for proton motion confined within the self-similar lattice of the metal-organic framework MOF-808. Here, water confined to specified geometries within the MOF pores gives rise to spatially distinct diffusive eigenmodes with characteristic relative entropies. We demonstrate that periodic radio frequency driving combined with gradient modulation yields entropy evolution through the selection of distinct diffusion modes. Frequency-resolved diffusion spectra connect these...

Operation-Induced BiVO4 Surface Reconstruction Modulates Photoelectrochemical Glycerol Photooxidation Stability and Activity

Thu, 7 May 2026 00:00:00 +0000

Operation-Induced BiVO4 Surface Reconstruction Modulates Photoelectrochemical Glycerol Photooxidation Stability and Activity

Oxygen-tolerant CO 2 capture using protected redox-driven reverse bias bipolar membrane electrodialysis

Wed, 6 May 2026 00:00:00 +0000

Electrochemical methods for carbon capture potentially have the advantage of low cost and low energy consumption. The practical applicability of pH-swing carbon capture processes driven by proton-coupled redox-active molecules has been limited by the sensitivity of reduced molecules to oxidation by O2. In those CO2 capture processes, the molecules are reduced, basifying the electrolyte; the electrolyte containing the reduced molecules is exposed to air or flue gas containing CO2 but also containing enough O2 to oxidize the molecules. O2 sensitivity would not be problematic if the electrolyte that captures CO2 contains the oxidized form of the molecule instead; this can be accomplished by switching from an electron-driven system to an ion-driven system. We report the development and performance of a two-chamber flow cell incorporating a reverse-bias bipolar membrane (BPM) and non-proton-coupled redox-active molecules for ion-driven pH-swing. When using ferri/ferrocyanide electrolytes...

Processing-Dependent Structure and Poroelasticity of Nafion in Liquid Water

Tue, 5 May 2026 00:00:00 +0000

Ionomers act as the solid polymer electrolyte membrane in many modern electrochemical devices, yet the role of their nanostructure in modulating the poroelastic response remains poorly understood, especially in liquid water, where few techniques can measure simultaneous transport-mechanical properties. Poroelastic Relaxation Indentation (PRI) is uniquely suited for measuring time-dependent transport-mechanical properties of porous solids, specifically hydraulic diffusivity, elastic modulus, Poisson’s ratio, and intrinsic permeability, for porous solids. While ionomers such as Nafion are not porous in the typical sense, Nafion has a nanophase-segregated structure that, when fully swollen in liquid water, behaves as a poroelastic solid with a coupled mechanical-transport response. Using a poroelastic framework, we investigate how casting and pretreatment of Nafion membranes alter their poroelastic response in liquid environments. We characterize both extruded and dispersion-cast...

Electronic Structure Tuning of Lanthanidocene Photocatalysts for C–F Bond Cleavage

Fri, 24 Apr 2026 00:00:00 +0000

A set of nine new robust, tunable cerium complexes supported by an ansa-bis(cyclopentadienyl) ligand, [Me₂Si(η⁵-Cp^R)₂]CeX (^anCp^R)CeX, are excellent homogeneous visible-light photocatalysts for the monodefluoroalkylation of trifluorotoluene with Mg(CH₂C₆H₅)₂THF₂ (R = Me₄, SiMe₃, X = N(SiMe₃)₂ (N″), X = CH(SiMe₃)₂ (R''), Cl, OC₆H₂^tBu₂-2,6,Me-4 (OAr)). The trends in photocatalytic activity within the series are explained by photophysical spectroscopic analyses. The aryloxide complex [Me₂Si(Cp^SiMe3)₂]CeOAr, which has the highest activity (95% substrate conversion in 27 h), shows the most negative (most reducing) excited-state reduction potential (-2.71 V vs Fc). The precatalyst excited-state...

Electron–electrophile coupled dinitrogen reduction in a cerium– meta -tetraphenolate system: a computational study

Fri, 24 Apr 2026 00:00:00 +0000

The use of lanthanide complexes for catalytic dinitrogen reduction is a new development in homogeneous catalysis. Density functional theory calculations on our recently reported cerium phenolate catalyst [K₂Ce₂(sol)₄(mTP)₂] (mTP = {(OC₆H₂-2-^tBu-4-Me)₂CH}₂-1,3-C₆H₄; sol = OMe₂ here; THF in the experiment) have been undertaken to elucidate the reduction, activation and silylation steps at the bound dinitrogen molecule, in the presence of the reductant, potassium metal (K⁰) and the electrophile Me₃SiCl (TMSCl). Out of the total of six electron reductions required to cleave the N₂, the first two-electron reduction step was found to be highly disfavoured unless potassium cations (K⁺) are included, upon which the step is rendered strongly exergonic; N-Si bond formation at the two-electron...

Quantitative Dissection of Agrobacterium Virulence to Generate a Synthetic Ti Plasmid

Fri, 24 Apr 2026 00:00:00 +0000

Agrobacterium is not only a costly plant pathogen but is also an essential tool for plant transformation. Though Agrobacterium-mediated transformation (AMT) has been heavily studied, its polygenic nature and complex transcriptional regulation make identification of the genetic basis of transformational efficiency difficult through traditional genetic and bioinformatic approaches. Here, we use a bottom-up synthetic approach to systematically engineer the tumor-inducing plasmid (pTi), wherein the majority of virulence machinery is encoded. Using a validated toolkit to control Agrobacterium gene expression in planta, we perform a quantitative dissection of AMT to investigate the contributions of critical vir-genes at different expression levels. We construct a synthetic pTi capable of transient plant and stable fungal transformation and characterize bottlenecks and solutions for complex polygenic synthetic pTi designs. Our reductionist approach...

An Algorithm for Atom-Centered Lossy Compression of the Atomic Orbital Basis in Density Functional Theory Calculations

Fri, 24 Apr 2026 00:00:00 +0000

Large atomic-orbital (AO) basis sets of at least triple and preferably quadruple-ζ (QZ) size are required to adequately converge Kohn-Sham density functional theory (DFT) calculations toward the complete basis set limit. However, incrementing the cardinal number by one nearly doubles the AO basis dimension, and the computational cost scales as the cube of the AO dimension, so this is very computationally demanding. In this work, we develop and test a threshold-based natural atomic orbital (NAO) scheme in which ϵ-NAOs are obtained as eigenfunctions of atomic blocks of the density matrix in a one-center orthogonalized representation. This enables compression of the AO basis that is optimal for a given threshold, 10^-ϵ, by discarding NAOs with occupation numbers below that threshold. Extensive pilot test calculations using the Hartree-Fock functional and taking the converged density matrix as input suggest that a threshold of 10^-5 can yield a compression factor...

Mapping the Undirected Borylation of C(sp3)–H Bonds in Strained Rings

Fri, 24 Apr 2026 00:00:00 +0000

Aliphatic small saturated carbocycles and azacycles are increasingly used as bioisosteres and structural cores in medicinally active compounds due to the beneficial pharmacological and physicochemical properties they can impart. Therefore, a need exists to modify these motifs and to install groups that enable their incorporation into organic structures; these goals can be accomplished by introducing functional groups at the position of the C-H bonds on the rings. However, functionalization of secondary C-H bonds in strained rings, such as cyclopropanes and cyclobutanes, confronts several challenges, including the greater strength of these bonds than those in unstrained rings. Although catalytic, undirected borylation has been reported to functionalize the C-H bonds of selected strained rings, the examples of such reactions in earlier studies are limited in scope, principally involving rings with a small number and size of substituents. We report the borylation of fused, spirocyclic,...

Synergistic ruthenium single-atom and nanoparticles in nickel as cooperative catalysts for the alkaline hydrogen evolution reaction

Thu, 23 Apr 2026 00:00:00 +0000

Efficient hydrogen evolution reaction (HER) catalysts that reduce the use of noble metals and can be synthesized on a large scale are essential for advancing anion exchange membrane water electrolyzers (AEMWEs) toward commercialization. Herein, we present a composite catalyst in which Ru nanoparticles coexist with Ru single-atom alloys (SAAs) dispersed within Ni nanoparticles (Ru-SAA/Ni), creating a highly active HER electrocatalyst. Using a one-pot and scalable synthesis method, we can tune the material composition from SAA, i.e. materials containing atomically dispersed Ru atoms (with ≤0.4 at% Ru) to composite structures in which SAAs coexist with Ru NPs. Comprehensive characterization using XPS, XAS, and TEM confirms Ru-SAA formation at a low Ru content and composite structures at higher contents. Electrochemical evaluations conducted in a three-electrode setup reveal that Ru-SAA/Ni composites achieve HER performance on par with that of Pt/C. Computational insights suggest...

Interlayer Exciton Condensates between Second Landau Level Orbitals in Double Bilayer Graphene

Thu, 23 Apr 2026 00:00:00 +0000

We present Coulomb-drag measurements on a heterostructure comprising two Bernal-stacked bilayer graphene (BLG) sheets separated by a 2.5 nm hexagonal boron nitride (hBN) spacer in the quantum Hall (QH) regime. Using top and bottom gate control, together with an interlayer bias, we independently tune the two BLG layers into either the lowest (N=0) or second (N=1) Landau level (LL) orbital and probe their interlayer QH states. When both layers occupy the N=0 orbital, we observe both interlayer exciton condensates (ECs) at integer total filling and interlayer fractional QH states, echoing the results in double monolayer graphene. In contrast to previous studies, however, when both BLG layers occupy the N=1 orbital, we also observe quantized drag signals, signifying an interlayer exciton condensate formed between the second LLs. By tuning the layer degree of freedom, we find that this N=1 EC state arises only when the N=1 wave function in each BLG is polarized toward the hBN...

Using Network Observations to Constrain CO and CO2 Emissions From an Oil Refinery in the San Francisco Bay Area

Wed, 22 Apr 2026 00:00:00 +0000

Abstract Point sources are often major contributors of greenhouse gas and air pollutant emissions in urban areas. Dense air monitoring networks provide a unique avenue for studying point source emissions over long time periods. Here, we use the Berkeley Environmental Air‐quality and CO 2 Network (BEACO 2 N) to study CO 2 and air pollutant emissions from an oil refinery in the city of Richmond, CA. We identify 266 plumes crossing one or more sites in the BEACO 2 N network during 2022–2023 as having a source at the refinery and quantify CO 2 emissions using the Gaussian plume model. The refinery is modeled as two point sources, and total CO 2 emissions are found to be 61.3 ± 6.3 kg s −1 , in close agreement with the EPA Facility Level Information on GreenHouse gases Tool inventory and Carbon Mapper measurements. Additionally, plume composition was found to vary, with CO/CO 2 enhancement ratios ranging from 0 to 5 ppb/ppm. Taking the average CO/CO 2 ratio,...

Observational Inferences of NO x and CO Emission Factors for Vehicles and Homes in the San Francisco Bay Area

Wed, 22 Apr 2026 00:00:00 +0000

We present the seasonal variations of enhancement ratios (ERs, i.e., ΔNO x /ΔCO2 and ΔCO/ΔCO2) as a function of distance from highways in the San Francisco Bay Area, using observations from the Berkeley Environmental Air Quality and CO2 Network (BEACO2N) at 40 locations. The spatial patterns exhibit exponential distance-decay relationships, with higher NO x and CO ERs near highways and more uniform ERs at distances beyond 3 km. These patterns are used to infer emission factors (EFs) for transportation and residential buildings. BEACO2N-derived EFs for CO (7.8 ± 0.6 ppbv/ppmv) and NO x (1.0 ± 0.02 ppbv/ppmv) from transportation agree with inventory estimates. In contrast, the residential NO x EF (0.15 ± 0.01 ppbv/ppmv) is four times lower than inventory estimates, and the residential CO EF (4.3 ± 0.3 ppbv/ppmv) is 33% lower than the California state inventory estimate.

Foundation models for atomistic simulation of chemistry and materials

Wed, 22 Apr 2026 00:00:00 +0000

Conventional computational methods for modeling chemical and materials systems are limited by system size and timescale, forcing a trade-off between quantum-mechanical accuracy and the sampling needed for realistic observables. Large language and vision foundation models — pre-trained on massive datasets using transformer architectures — have revolutionized many fields. It is thus interesting to ask whether a foundation model — subject to suitable data, parameter scaling and training — could enable learned simulations of chemistry and materials. Here, we review the field of machine-learned interatomic potentials (MLIPs) and posit that scaling up large and diverse chemical and materials datasets and highly expressive architectures using advanced training strategies should result in models that are: more efficient, transferable, robust to out-of-distribution scenarios, and easier to fine-tune to a variety of downstream physical observables than models trained from scratch on...

Impacts of wildfire smoke aerosols on near-surface ozone photochemistry

Wed, 22 Apr 2026 00:00:00 +0000

Abstract. Wildfires have been an increasing concern for the environment, yet the ozone (O3) production from wildfires remains poorly characterized. Here, we aim to elucidate the role of aerosols from wildfire smoke in near-surface O3 photochemistry by integrating insights from a 0-D box model (F0AM) to a 3-D chemical transport model (GEOS-Chem). While smoke aerosols typically inhibit O3 production through heterogeneous chemical and radiative pathways, we find that for most fires, the O3 enhancement driven by precursor emissions outweighs these aerosol-driven suppression effects. The relative importance of the two aerosol effects varies, with the heterogeneous chemical effect generally overshadowing the radiative effect in the far field of fires. However, near the sources of extremely large fires, the radiative effect dominates, leading to an overall suppression of O3 production. By assessing the chain termination of hydrogen oxide radicals (HOx) and introducing the “light-limited”...

Local pH control for impure-water-fed bipolar-membrane electrolyzers

Wed, 22 Apr 2026 00:00:00 +0000

Local pH control for impure-water-fed bipolar-membrane electrolyzers

Electronic Band Structures of a Germanium Halide Perovskite Semiconductor

Tue, 21 Apr 2026 00:00:00 +0000

CsGeX3, a class of halide perovskites, is an emergent semiconductor with ferroelectricity and potential optoelectronic properties that can be harnessed for device applications. However, measurements of the electronic structure for this class of material are still lacking. In this work, we report, for the first time, the experimental band structures of CsGeI3, a ferroelectric halide perovskite semiconductor, through angle-resolved photoemission spectroscopy (ARPES). The crystals were cleaved along both the (110) and (111) surfaces, facilitating the observation of clear valence band dispersions in several high-symmetry momentum directions. The observed valence band is characterized by a small hole effective mass of ∼0.1m 0 at the valence band maximum, without notable spectral signatures associated with the Rashba effect. Our experimental measurements are supported by electronic structure calculations in the DFT + G0W0 framework, enabling assessment of the band orbital characteristics,...

Gate-All-Around Nanowire Field-Effect Transistors: A Historical Perspective

Tue, 21 Apr 2026 00:00:00 +0000

The development of transistor architectures, evolving from 2D planar metal-oxide-semiconductor field-effect transistors (MOSFETs) to FinFETs and then to gate-all-around nanowire (GAANW) FETs, plays a crucial role in downscaling technology nodes in the semiconductor industry. This perspective reviews the concept of MOSFETs and summarizes this historical development with particular emphasis on GAANW transistors due to their importance in next-generation technology for nodes below 3 nm. Specifically, the concept of GAANW transistors and their advantages over planar and FinFET devices for further scaling are presented, along with a discussion of their transition from early conceptual ideas to laboratory demonstrations and, ultimately, industrial adoption. Furthermore, potential solutions, such as complementary FETs (CFETs) and 2D semiconductor-based FETs, and their associated challenges for the future generation, known as the Angstrom Era, are discussed in a technological roadmap....

Polymer‐Assisted Supercooled Lithium Salts: Nonflammable Single‐Ion Conducting Liquid Electrolytes for Next‐Generation Batteries

Tue, 21 Apr 2026 00:00:00 +0000

ABSTRACT Electrolytes that exhibit both high ionic conductivity and a near‐unity Li + transference number ( t Li ) are essential for next‐generation rechargeable batteries. Here, we present solvent‐free liquid electrolytes based on polymer‐assisted supercooled lithium salts that realize single‐ion conduction under ambient conditions. A trace amount of poly(methyl methacrylate) suppresses crystallization, stabilizing low‐melting Li salts in a deeply supercooled liquid state while retaining t Li ≈ 1. To further enhance ion transport, we employ a dual‐salt strategy, which lowers the glass transition temperature and increases ionic conductivity without compromising the near‐unity t Li . Despite moderate conductivity compared with conventional electrolytes, these supercooled salts suppress concentration overpotentials and support stable cycling in Li/LiCoO 2 cells. The intrinsic adhesive properties of the electrolytes enable the fabrication of binder‐free thick cathodes with high...

Tandem Electrolyzer–Chemostats for Synthesizing Bioplastics from CO2 and H2O

Tue, 21 Apr 2026 00:00:00 +0000

Harnessing renewable energy to convert anthropogenic CO2 to valuable products is central to establishing a sustainable carbon cycle. Here, we present a continuous electrobiocatalytic platform for converting CO2 to Bioplastic by using an external water-splitting electrolyzer integrated with a two-stage cascade of continuous stirred-tank bioreactors (CSTBs) arranged in tandem, a system-level architecture that has not been previously reported. A proton exchange membrane (PEM) electrolyzer produces H2 for the acetogenic bacterium Sporomusa ovata, which fixes CO2 into acetate in CSTB 1, achieving a steady-state productivity of 293 ± 17 mg L–1 h–1. The acetate is continuously and directly supplied to CSTB 2 and subsequently metabolized by the facultative chemolithoautotroph Cupriavidus necator for the biosynthesis of poly(3-hydroxybutyrate) (PHB) biopolymers. Under steady-state conditions, the electrolyzer/CSTB 1/CSTB 2 system achieves a PHB productivity of 2.76 ± 0.24 mg L–1 h–1, which...

A Combined Experimental and Theoretical Investigation of Arene-Supported Actinide and Ytterbium Tetraphenolate Complexes

Tue, 21 Apr 2026 00:00:00 +0000

Modular tetraphenolate ligands tethered with a protective arene platform (para-phenyl or para-terphenyl) are used to support mononuclear An(IV) (An = Th, U) complexes with an exceptionally large and open axial coordination site at the metal. The base-free complexes and a series of neutral donor adducts were synthesized and characterized by spectroscopies and single-crystal X-ray diffraction. Anionic Th(IV) -ate complexes with an additional axial aryloxide ligand were also synthesized and characterized. The para-phenyl-tethered mononuclear complexes exhibit rare An(IV)-arene interactions, and the An(IV)-arene distance broadly increases with axial donor strength. The para-terphenyl-tethered complexes have almost no interaction with the arene base, isolating the central metal cation. Computational analysis of the mononuclear complexes and their reduced analogues, and Yb(III) congeners, as well as the effect of additional donor ligand binding, seek to elucidate...

Supramolecular assembly of molecular wires alternating crown ethers and metal–halide complexes

Thu, 16 Apr 2026 00:00:00 +0000

Metal–halide complexes serve as key emissive centres in halide perovskites; however, precise control over their spatial organization through bottom-up assembly is challenging. Here we show that a crown-ether-assisted supramolecular assembly strategy can alternatingly connect metal–halide complexes and (crown ether@A)2+ (where ‘A’ is an alkaline earth metal cation) complexes into a one-dimensional molecular wire, which can then be packed into a hexagonal crystal structure. This process resulted in the creation of an (18C6@Ba)MnBr4 single crystal with green emission, achieving over 80% photoluminescence quantum yield and a narrow full width at half maximum. In addition, the non-centrosymmetric crystal structure gave rise to strong nonlinear optical responses, including second-harmonic generation. This versatile supramolecular assembly approach could be generalized to create various [M(I)X2]−, [M(I)X3]2−, [M(II)X4]2− and [M(III)X5]2− molecular wires, broadening the potential for...

Coherent and Dynamic Small Polaron Delocalization in CuFeO2

Thu, 16 Apr 2026 00:00:00 +0000

Small polarons remain a bottleneck in realizing efficient transition metal oxide devices. Routes to engineer small polaron coupling to electronic states and lattice modes to control carrier localization remain unclear. Here, we measure small polaron formation in CuFeO₂ using transient extreme ultraviolet reflection spectroscopy and compare to theoretical predictions in realistically parametrized Holstein models, demonstrating that polaron localization depends on coupling to high-frequency versus low-frequency phonon bath components. We measure small polaron formation on a comparable ∼100 fs timescale to other Fe(III) compounds. Dynamic delocalization of the polaron follows formation through a coherent lattice expansion between Fe-O layers and charge-sharing with surrounding Fe(IV) states. Simulations reveal two major factors dictate polaron formation timescales: phonon density and reorganization energy distributions between acoustic and optical modes, matching experimental...

Molecular Weight-Controlled Cationic Polymerization of Tetrahydrofuran Using a Squaramidinium Hydrogen-Bond Donor Catalyst

Mon, 13 Apr 2026 00:00:00 +0000

Poly(tetrahydrofuran) (PTHF) has long-standing industrial relevance as the soft block of elastic fibers and thermosets. Despite its commercial importance, the synthesis of PTHF with molecular weight (MW) control beyond 20 kDa has proved challenging. In this work, we disclose a MW-controlled synthesis of PTHF up to 175 kDa by cationic ring-opening polymerization, using a cationic squaramidinium hydrogen-bond donor (HBD) catalyst in combination with an α-phosphonooxymethyl ether initiator at room temperature. Mechanistic studies support a reversible-deactivation polymerization pathway, wherein the HBD catalyst facilitates the anchimeric ionization of the primary alkyl phosphate chain end, generating the propagating oxonium species. The stability of the phosphate chain end was demonstrated by isolating PTHF with high chain-end fidelity and subsequently extending the PTHF macroinitiator to higher molecular weights. This system was further applied to the copolymerization of THF and...

Out-of-contact peeling caused by elastohydrodynamic deformation during viscous adhesion