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Ti3+-O Acid–Base Pairs for Efficient Solar-Driven Photothermal Nonoxidative Ethane Dehydrogenation
Abstract Nonoxidative ethane dehydrogenation (NOEDH) is a carbon efficient but thermodynamically severe route for ethene production. Solar-driven NOEDH offers a promising alternative, yet achieving both high activity and high ethene selectivity over noble metal-free catalysts without external heating remains unresolved. Here, we reported that Ti3+-O acid–base pairs on reduced rutile TiO2 enabled highly efficient full-spectrum solar-driven photothermal NOEDH without any external heating. The optimally reduced TiO2 at 750 °C delivered an ethene production rate of 392.0 mmol g–1 h–1, which was 1107 times higher than that of pristine TiO2 without reduction pretreatment. The high activity with a C2H4 selectivity of 94.9% surpassed the thermodynamic equilibrium limit and outperformed previously reported systems. Comprehensive characterizations identified surface Ti3+ sites adjacent to lattice oxygen as Lewis acid–base pairs that enhanced light absorption, promoted charge carrier separation, and directly participated in the C–H bond cleavage. Photogenerated electrons also preferentially accumulated on the coordinatively unsaturated Ti3+-O sites, which weakened ethene adsorption, thereby accelerating product desorption and suppressing deep dehydrogenation and coke formation. The synergy between photogenerated hot carriers and localized photothermal heating lowered the apparent activation energy from 157.6 kJ mol–1 in the dark to 75.0 kJ mol–1 under illumination. This work establishes surface acid–base pairs on noble metal-free catalyst as a powerful platform for sustainable light-driven alkane upgrading.
Total Synthesis of Benthol A: Evidence for a Structure Revision
Abstract Benthol A, a dinoflagellate-derived polyol/polyether marine natural product endowed with potent antimalaria and appreciable antiviral activity, consists of a 72 C atom linear backbone featuring 35 stereogenic centers and four stereogenic alkenes. The constitution and configuration of this intriguing “super-carbon-chain compound” had been assigned by the isolation team by a combination of spectroscopic, chemical, and computational means. Outlined in this and the accompanying paper is the first total synthesis of this challenging target, which came along with a subtle structure revision. During the synthesis of the building blocks, a spectral irregularity was noticed in that the 13C NMR chemical shifts as well as some of the 3JH,H coupling constants of the synthetic samples deviated notably from the data reported for the entire C31–C41 region of benthol A corresponding to the tetrahydropyran E-ring and its vicinity. A systematic approach made it possible to narrow down the likely site of error to a single, incorrectly assigned stereocenter, i.e., the C40 position; interestingly, the configuration of this site had been determined by the isolation team solely by computational means. In chemical terms, our studies showed how the proper choice of a propargylic protecting group allows the regiochemical course of a gold-catalyzed spiroacetalization reaction to be steered. Moreover, carbonyl homologation by the addition of a highly functionalized but entirely unstabilized diazo derivative generated in situ to an equally highly functionalized aldehyde proved adequate for the coupling of elaborate building blocks (Buchner–Curtius–Schlotterbeck reaction).
Accelerated Self-Photopolymerization of Phenolics in Microdroplets Contributes to the Brown Carbon Formation
Abstract While phenolic compounds are recognized as key atmospheric precursors of brown carbon (BrC), the mechanisms governing their interfacial transformation into BrC aerosols, particularly at the microdroplet air–water interface (AWI), remain incompletely characterized. This study investigated the photolysis of phenolic compounds in microdroplets under UV irradiation, revealing a transformation efficiency 2 orders of magnitude higher than that in bulk solutions. Through integrated Fourier transform ion cyclotron resonance mass spectrometry, liquid chromatography–mass spectrometry, and fluorescence excitation–emission matrix spectrum, we identified interfacial-confined oligomerization as the dominant pathway generating BrC with oligomer characteristics. Multiscale theoretical simulations unveiled that the AWI functions as a key mediator through a synergistic mechanism: it not only drives the spontaneous accumulation of phenols at the interface, but also enhances their photon absorption efficiency via asymmetric interfacial H-π hydrogen bonding, as evidenced by a critical 24.7% increase in the molar extinction coefficient at 298 nm. Together, these dual effects synergistically facilitate photon capture and subsequent phenoxy radical generation. Our results establish the AWI as photochemical nanoreactors that fundamentally alter atmospheric BrC formation kinetics, providing a mechanistic framework to reconcile field observations of rapid aerosol aging under humid conditions, while challenging current model assumptions about phenolic transformation time scales.
Deciphering the Specificity of Reversible DNA-Phosphate ADP-Ribosylation via the Precise Synthesis and Enzymatic Profiling of Nucleotide-Phospho-ADP-Ribosyl Probes
Abstract ADP-ribosylation (ADPr), long recognized as a canonical protein post-translational modification, has recently expanded to include targeting nucleic acids, uncovering a diverse landscape of noncanonical biological functions. Emerging evidence suggests that ADPr at the 5′-phosphate terminus of DNA is implicated in the DNA damage response, yet understanding its precise molecular function has been hampered by the lack of structurally defined chemical probes. Here, we report the stereoselective synthesis of deoxynucleotide-phospho-ADPr (dN-P-ADPr) probes, representing native fragments of terminal DNA-ADPr. Our strategy leverages a mild, stereocontrolled glycosylation to construct the challenging ribosyl-phosphate linkage, followed by P(III)–P(V) coupling to establish the pyrophosphate bridge. This robust toolkit enabled the systematic biochemical profiling of DNA-ADPr hydrolases across diverse kingdoms of life. Remarkably, using these newly developed probes, we uncover hydrolases across the diversity of life capable of reversing ADPr modifications at phosphorylated DNA ends. We further show that these enzymes exhibit an absolute preference for the native-like α-anomer, independent of the identity of the adjacent DNA nucleobase, suggesting that substrate recognition is governed primarily by the ADPr-phosphate linkages rather than the local nucleobase context. Together, these synthetic probes and biochemical insights provide an essential foundation for deciphering the biological landscape of noncanonical ADPr.
Engineering Altermagnetic Transitions in Two-Dimensional Metal–Organic Frameworks via Chemical Symmetry Breaking
Abstract Altermagnets are symmetry-defined magnetic phases that combine momentum-dependent spin splitting with zero net magnetization, offering promising opportunities for spintronics. However, their realization is strongly constrained by rigorous symmetry requirements. Exploiting the shared antiparallel magnetic order and vanishing net magnetization between antiferromagnets and altermagnets, we propose a general chemically driven strategy based on asymmetric ligand modification to transform pristine two-dimensional antiferromagnetic metal–organic frameworks into altermagnetic candidates. Using chromium phthalocyanine (CrPc) as a proof-of-concept model, we show that asymmetric modification lowers the local site symmetry at magnetic Cr centers and generates momentum-dependent spin splitting and anisotropic spin densities, as revealed by first-principles calculations. Oxygen-modified CrPc derivatives further illustrate the chemical tunability of this symmetry-control principle. Our work expands the design space of organic altermagnetic candidates and establishes a chemically grounded route for engineering symmetry-governed magnetic functionality in reticular materials.
Total Synthesis of Benthol A: The Nominal and the Actual Natural Product
Abstract The total synthesis of the dinoflagellate-derived “super-carbon-chain compound” benthol A rigorously confirmed what the analysis of one of the required building blocks had forecasted, namely that the configuration of the secondary −OH group at C40 had been misassigned by the isolation team as the only one of a total of 35 stereogenic centers decorating the backbone of this polyol/polyether derivative. This conclusion bears implications because the original assignment had been solely based on computational data, which had resulted in a remarkably high score of 99.93% that was ultimately misleading. The multiconvergent blueprint underlying the successful approach accounts for the fact that alongest linear sequence of 32 steps sufficed to reach this intricate marine natural product. The inherent flexibility should also empower future studies aiming at a detailed mapping of the pharmacophore of this compound endowed with significant antiplasmodial activity.
Zero Indirect Band Gap and Flat Bands in a Niobium Oxyiodide Cluster Material
Abstract Explorative chemistry in a reaction system composed of NbI4, Li2(CN2), and Li2O has led to the discovery of a number of niobium oxyiodide cluster compounds. During this reaction, the formation of solid phases was detected alongside gaseous phases, resulting in a range of products with cluster cores of varying shapes. After several niobium oxyiodide cluster compounds have already been identified within this reaction system, two additional compounds, Nb6O3I15 and Nb11O6I24, are discovered and structurally characterized by single-crystal X-ray diffraction. Both structures are based on the butterfly-shaped, oxygen-capped niobium cluster [Nb4O], which is extended to larger cluster fragments. The [Nb4O] cluster core in Nb6O3I15 is extended by two [NbO] units to form a three-dimensional framework, and Nb11O6I24 contains two connected [Nb4O] units, which form chiral units within an antiferrochiral hexagonal packing of strings. The striking string-like character of Nb11O6I24 was investigated in terms of its electronic structure and properties. DFT calculations showed Nb11O6I24 to possess a zero indirect band gap, with a pair of 3-dimensional flat bands surrounding the Fermi level. These unusual features of the electronic band structure suggest the presence of strongly correlated intercluster singlet electron states, arising from the helical shape of the clusters, the hexagonal packing of the strings, and the delocalized nature of cluster electron wave functions.
Influence of Halide Substitution on Local and Average Structure, Lattice Dynamics, and Transport Properties in Cu6PS5X Argyrodites
Abstract Halide-substituted argyrodite materials have attracted increasing attention for energy applications since compositional tuning provides an effective strategy to modulate their structure and transport characteristics. While Li+-based halide argyrodites have been extensively studied, a unified composition-resolved understanding of Cu+-based halide argyrodites that integrates phase evolution, local structure, lattice dynamics, and electronic and ionic transport remain limited. In this work, we investigate Cu6PS5X (X = Cl, Br, I, Cl0.5Br0.5, Cl0.5I0.5, and Br0.5I0.5) within a combined experimental and computational framework. All compositions adopt an average cubic F4̅3m structure at room temperature, while local structural analysis reveals deviations from cubic symmetry consistent with a monoclinic Cc model involving PS43– tetrahedral tilting. 31P MAS NMR spectroscopy corroborates this local symmetry breaking through multiple distinct phosphorus environments arising from relative tetrahedral orientation rather than S2–/X– site disorder. Halide substitution modifies the Cu+ conductivity through changes in the activation energy and the Arrhenius pre-exponential factor, following the Meyer–Neldel behavior, with additional contributions from variations in jump distances and migration pathways. Direction-projected phonon density of states analysis identifies low-frequency Cu+ vibrational components along the crystallographic migration pathways. Analysis of the Meyer–Neldel slope further suggests phonon assisted ion hopping involving multiphonon excitation of low-frequency Cu+ vibrational modes. Together, these findings offer insight into structure–property relationships in Cu6PS5X and suggest that, alongside the migration energy landscape, the vibrational energy scale, thermal population, and directionality of mobile ion modes should be considered when interpreting ion transport, thereby providing a vibrational perspective for the design of solid-state ion conductors.
Understanding Electrochemical Alcohol Hydrogenolysis Enabled by Carbonyl Reduction in Lignocellulosic Biomass-Derived Aromatic Oxygenates
Abstract Molecules derived from lignocellulosic biomass are oxygenates with multiple oxygen-containing functional groups, such as hydroxyl and carbonyl groups. Therefore, the ability to selectively reduce a specific oxygenate group is essential for the reductive upgrading of such molecules. Previous studies on electrochemical biomass conversion have shown that alcohol hydrogenolysis, which involves cleavage of the σ(C–Oalcohol) bond, is extremely challenging for furfural and 5-hydroxymethylfurfural (HMF) derivatives, including furfuryl alcohol, 5-methylfurfuryl alcohol (MFA), and 2,5-bis(hydroxymethyl)furan (BHMF). In contrast, HMF itself undergoes alcohol hydrogenolysis relatively easily in acidic aqueous media. Considering that the only structural difference between HMF and BHMF or MFA is the presence of a carbonyl group, this observation raises the question of whether the carbonyl group in HMF facilitates alcohol hydrogenolysis. In this study, we designed systematic experiments to provide a coherent explanation of when and how a carbonyl group enables hydrogenolysis of a copresent alcohol group. Specifically, we show that alcohol hydrogenolysis in HMF proceeds via reduction of the carbonyl group to a ketyl radical, followed by a spin-center shift (SCS) through extended π conjugation. We also elucidate the effect of pH on the selectivity between carbonyl hydrogenation and alcohol hydrogenolysis, both of which share the ketyl radical intermediate. This mechanistic understanding enhances our ability to predict and control alcohol hydrogenolysis in the reductive upgrading of biomass-derived oxygenates.
Facile Fabrication of Redox-Active Covalent Organic Frameworks via Reductive <i>N</i> -methylation
Abstract Redox-active covalent organic frameworks (COFs) are promising materials for electronics, sensing, and catalysis. However, their synthesis is hampered by the scarcity of redox-active monomers and the difficulty of functionalizing as-synthesized frameworks without compromising crystallinity. Here, we introduce a reductive N-methylation strategy that enables the universal and mild conversion of imine-linked COFs into crystalline tertiary amine-linked frameworks (NMe-COFs). The method preserves structural order while imparting strong electron-donating and redox-responsive properties. Among the NMe-COFs, COF-300-NMe exhibits an 11-fold increase in iodine uptake with a distinct gate-opening adsorption profile─a behavior that computational studies attribute to enhanced framework flexibility and raised electronic energy levels. Furthermore, incorporation of the electron acceptor 7,7,8,8-tetracyanoquinodimethane into COF-300-NMe yields a charge-transfer complex exhibiting distinct spin signatures. This work establishes a versatile postsynthetic linkage conversion strategy, paving the way toward stimuli-responsive soft COFs and purely organic spin-active materials.
In Situ Unveiling of the Coupling Mechanism of Intercalation-Conversion Processes at the Nanoscale in Lithium–Ion/Lithium–Oxygen Hybrid Batteries
Abstract With the rapid growth in energy demand, designing a novel hybrid battery system has become increasingly important. It is critical to reveal the coupling mechanisms of intercalation-conversion hybrid cathodes and provide an in-depth understanding of structure-performance relationships for the electrochemical energy storage devices with high energy density. In this study, a hybrid cathode that combines intercalation-type LiNixCoyMn1-x-yO2 (NCM) with conversion-type oxygen (O2) is proposed. Using in situ electrochemical atomic force microscopy (EC-AFM), we elucidate that the overlithiation of the NCM cathode enhances electronic conductivity and exposes abundant active sites during discharge, thereby inducing the formation of Li2O2. Electrochemical tests demonstrate that the contributions of intercalation and conversion reactions to capacity are rate-dependent, with lower rates favoring the intercalation-dominated electrochemical process. Further scanning transmission electron microscopy characterization indicates that, during prolonged cycling, oxygen vacancies in the NCM intercalation-type cathode serve as preferential sites for the conversion-type Li–O2 intermediates, significantly enhancing the cycling stability of the battery. Ultimately, by optimizing the mass ratio between the intercalation and conversion cathodes, an enhanced cycle stability is achieved. This study offers valuable insights into modulating battery performance through multimechanism reactions in hybrid battery systems.
Multidomain Relaxation Dispersion NMR Resolves an Intermediate-Gated Binding Pathway for Selective Recognition of Linear Diubiquitin by HOIL-1L
Abstract Molecular recognition is governed not only by the structural complementarity of the final complex, but by the kinetic pathway through which it forms. Polyubiquitin chains, in which sequence-identical domains are covalently linked yet must be discriminated by dedicated receptors to encode distinct cellular signals, exemplify this challenge. For NMR relaxation dispersion studies of such systems, spectral overlap between identical domains prevents conventional uniform isotope labeling from resolving the per-domain exchange contributions. Here we show, using domain-selective 15N labeling combined with R2 relaxation dispersion, that the binding of linear (Met1-linked) diubiquitin to HOIL-1L NZF proceeds through an apparent three-state pathway as detected by relaxation dispersion, in which rapid ligand-dependent pre-equilibration populates a conformationally preorganized intermediate that is selectively captured by NZF in a slower, chain-type-selective step. This kinetic hierarchy offers a mechanistic basis for understanding the discrimination between linear and Lys63-linked ubiquitin chains that static structures alone cannot reveal. This strategy should be broadly applicable to multidomain recognition systems─including epigenetic reader complexes and multivalent signaling adaptors─where the pathway between known structural end points remains hidden.
Arraying Shape-Persistent Molecular Alkynyl Trap into Highly Porous and Robust Zirconium Metal–Organic Framework for Propyne Capture and Propyne/Propylene Separation
Abstract Adsorptive separation of propyne/propylene (C3H4/C3H6) using porous adsorbents offers a promising route toward energy-efficient production of polymer-grade C3H6. Currently, the prevailing adsorbents are ultramicroporous metal–organic frameworks (MOFs) that feature narrow channels and/or consist of inorganic anion pillars, which often lead to limited C3H4 uptake capacity and high isosteric enthalpy of adsorption. We report herein a highly porous and robust zirconium metal–organic framework, termed SJTU-520. This MOF incorporates shape-persistent molecular arrays in three-dimensional space derived from cyclotetrabenzoin, which function as selective sites for the preferential entrapment of C3H4 over C3H6, thus enabling high C3H4 capture capacity, record high C3H4/C3H6 uptake ratio at 1 bar and 298 K, and efficient C3H4/C3H6 separation at ambient conditions. Compared with the cyclotetrabenzoin and tetraacetate cyclotetrabenzoin-based supramolecular organic crystals, SJTU-520 exhibits significantly higher surface area (3650 m2/g versus 42 and 570 m2/g), leading to a C3H4 uptake boost by 6.1-fold and 3.7-fold at 298 K and 1 bar, without any compromise of the C3H4/C3H6 selectivity. The efficient C3H4/C3H6 separation was validated by extensive breakthrough experiments under various conditions with great recyclability and high productivity of polymer-grade C3H6 from a 10/90 C3H4/C3H6 mixture. Computational simulations revealed that the four benzene walls of the cyclotetrabenzoin macrocycle in SJTU-520 formed equidistant π–π interactions with the C≡C triple bond of encapsulated C3H4 molecule. This work illustrates a general and powerful strategy─the reticulation of intrinsically functional organic scaffolds into highly porous frameworks─toward creating bespoke materials with precisely tailored functionalities and enhanced properties.
Dedioxygenative Phosphonylation of Carboxylic Acids
Abstract Dedioxygenative transformations of carboxylic acids are faced with the significant challenges in efficiently breaking multiple C–O bonds and achieving broad applicability across diverse carboxylic acids, thereby hampering the development and application of this field. In this work, through the cooperation of multiple catalysts, we realized a dedioxygenative phosphonylation of carboxylic acids that is applicable to both aliphatic and aromatic substrates, showing good scope and functional-group tolerance. This protocol also demonstrates promising performance in the late-stage modification of complex molecules. Meanwhile, it establishes a formal deoxygenative coupling approach that enables rapid access to alkenes from carboxylic acids and aldehydes or alcohols. Mechanistic studies reveal distinct activation modes for different C–O bonds and further highlight a carbon-retentive transformation pattern of carboxylic acids, complementing conventional carbon-deletion decarboxylative phosphonylation based on redox-active esters or other strategies.
Origins of Reactivity in SAM-Utilizing Ribozyme SAMURI-Catalyzed RNA Alkylation
Abstract Unlocking the design principles of programmable RNA catalysts capable of site-specific chemical modification is critical for expanding the functional and therapeutic potential of RNA. The SAM analogue-utilizing ribozyme (SAMURI) enables site-specific RNA alkylation using either S-adenosylmethionine (SAM) or the synthetic cofactor propargylic Se-2,6-diaminopurinribosyl-selenomethionineamide (ProSeDMA), yet the molecular determinants of its reactivity remain incompletely understood. Here, we combined molecular dynamics, 3D-RISM solvation analysis, alchemical free energy calculations, quantum pKa shift predictions, and ab initio QM/MM free energy simulations to characterize the conformational and electronic factors that govern catalysis. Simulations show that, although the global fold of SAMURI remains stable in solution, the formation of catalytically competent near-attack configurations is rare, indicating that the observed rate depends on access to a minor fraction of these reactive conformations (freact). A putative Mg2+ binding site between the SAM carboxylate and the G30 phosphate, together with a hydrogen bond between the cofactor α-amine and U8:O2, enriches freact. QM/MM simulations support an SN2-like alkyl transfer mechanism and show that ProSeDMA reacts more readily than SAM primarily due to its more favorable electronic leaving group properties that enhance the intrinsic rate (kint). Atomic substitutions at A52 that tune the N3 pKa enhance nucleophilicity, further lower the activation barrier, and increase kint. Together, these results show that SAMURI catalysis is governed by a combination of conformational preorganization and electronic effects, providing a framework to guide the design of new programmable RNA alkyltransferases.
High-Pressure Investigation of the I–N System: Discovery of the Nitric Ozonide [N3]3– (“Ozonitride”) Species and Multicenter Bonding in Iodine Frameworks
Abstract Despite binary nitrides being heavily investigated at high pressures in the past decade, nitrogen halides are still a terra incognita at pressures exceeding 1 bar. Due to the unique chemistry of halogens, they are fertile grounds for the discovery of novel nitrogen species. Here, we report the high-pressure investigation of the I–N system up to 120 GPa using laser-heated diamond anvil cells and the synthesis of the first two thermodynamically stable binary iodine–nitrogen compounds, I4(N2)3 and I2(N2)(N3), formed from 81 and 95 GPa, respectively. Their crystal structures were solved and refined through synchrotron single-crystal X-ray diffraction measurements. I4(N2)3 is comprised of a layered polymeric iodine framework of hexagonal iodine units and infinite linear iodine chains─both evidenced to feature multicenter bonding─along with N2 dimers. In contrast, I2(N2)(N3) exhibits corrugated and distorted I6 layers along with N2 dimers as well as a hitherto unknown nitrogen species, [N3]3–. This anion is both isosteric and isoelectronic with ozone (O3), leading to its designation as a nitric ozonide (or “ozonitride” for simplicity). The stability domain of each compound is investigated, and their bulk modulus determined. Accompanying density functional theory calculations provide further insight into the crystal chemistry, stability regime, and physical properties of the two iodine–nitrogen compounds.
Supramolecular Predisposition Promotes Intramolecular Heavy-Atom Effects for Self-Sensitized Oxidation
Abstract Supramolecular confinement is widely used to control molecular architecture, but its use to direct excited-state reaction pathways remains underexplored. This limitation is particularly evident for spin-forbidden processes such as intersystem crossing (ISC), which are difficult to regulate through supramolecular design. The heavy-atom effect, although central to promoting ISC, is typically regarded as an intrinsic substituent property rather than a geometry-dependent supramolecular parameter. Here we show that macrocycle-directed supramolecular predisposition can deliberately enforce intramolecular heavy-atom effects to activate latent spin-forbidden transitions, enabling efficient self-sensitized oxidation. Encapsulation of a flexible aldehyde- and bromine-substituted guest within cucurbit[8]uril (CB[8]) enforces a folded geometry that juxtaposes the heavy atom and reactive aldehyde, as established by solution studies and single-crystal analysis. Under white-light irradiation, this predisposed complex undergoes selective oxidation of the aldehyde to the corresponding carboxylic acid. Control experiments varying heavy-atom identity, cavity size, and guest binding modes define CB[8]-enforced spatial juxtaposition as the critical structural requirement, while scavenger and EPR studies support triplet-oxygen energy transfer to generate singlet oxygen as the operative pathway. Preferential binding of CB[8] to the substrate over the product mitigates product inhibition and allows catalytic turnover under substoichiometric host loadings. These results show that macrocyclic encapsulation does more than statically stabilize a host−guest complex: it transforms spatial geometry into a structurally gated switch for spin-forbidden pathways, establishing supramolecular predisposition as a versatile design principle for developing switchable photocatalysts and conformationally responsive smart materials.
Spinterface-like Mechanism of the Chirality-Induced Spin Selectivity in Donor–Chiral Bridge–Acceptor Complexes
Abstract The chirality-induced spin selectivity (CISS) effect has been invoked to explain recent reports of differences in the time-resolved EPR signals between chiral and achiral molecules. However, the microscopic origin of these differences and their connection to CISS remain contested, particularly since these systems lack a metal interface. Here, we introduce an intramolecular spinterface-like mechanism that naturally arises within donor–chiral bridge–acceptor (D−χB–A) complexes and quantitatively reproduces experimentally reported observed spin polarization in time-resolved EPR studies. In our two-electron Lindblad model, the photoexcited charge-transfer electron traversing the chiral bridge exchanges with the residual donor electron, which acts as a localized magnetic moment analogous to an induced magnetic moment on an electrode surface. The resulting through-bridge charge current produces an effective solenoidal field at the donor–bridge interface, breaking spin degeneracy and directional symmetry, thus enabling spin-selective transport without invoking intrinsic spin–orbit coupling on the bridge. We show that the interplay among this current-induced field, donor thermalization (which breaks time-reversal symmetry), and bridge spin mixing yields tens-of-percent polarization over realistic experimental conditions and charge-transfer time scales, matching reported CISS signatures in triads and DNA hairpins. By explicitly resolving the dependence on solenoidal coupling strength, temperature, and spin-mixing rates, the model identifies the regime in which internal spinterfaces can generate robust CISS-like spin filtering. These findings demonstrate that CISS-like signals in isolated D−χB–A complexes are fully compatible with a spinterface mechanism, providing a unified conceptual framework for interpreting both device-based and molecule-internal CISS platforms.
Structural Chemistry of [V2As17]3– and [V2Sb17]4–: A Complex Interplay between V-Pn and Pn-Pn Bonding
Abstract The ability of the heavier pnictogen elements, P, As, Sb and Bi, to form extensively catenated structures is well established, and a wide range of architectures is known, both for the isolated ions and for their coordination complexes. In this work, we report two new vanadium clusters, [V2As17]3– and [V2Sb17]4–, which contain crown-like VPn8 units, linked by a single bridging atom. Reaction monitoring using ESI-MS suggests a growth pathway involving both VPn8 and VPn9 units, the latter appearing transiently in the reaction mixture. Density functional theory reveals that the redox-active orbital has Pn–Pn antibonding character: the two clusters can therefore be considered to map a segment of the potential energy surface linking the entirely separated fragments to a single fused Pn17 unit.
Reprogramming ThDP Enzymes for <i>Z</i> -Alkenes: Overriding Thermodynamic Preference via Noncovalent Controls
Abstract Most conventional alkene synthesis reactions (e.g., elimination et al.) inherently favor the formation of thermodynamically more stable E-isomers, posing a long-standing challenge for direct access to Z-alkenes. Here, we report the reprogramming of a thiamine diphosphate (ThDP)-dependent enzyme to catalyze a formal dehalogenative elimination that overrides this intrinsic thermodynamic bias, enabling the direct and selective synthesis of Z-α,β-unsaturated carboxylic acids. In contrast to classical approaches that rely on substrate control, directing groups, or complex ligand architectures, our strategy harnesses the enzyme’s confined active site to achieve kinetic control exclusively via noncovalent interactions─representing a fundamentally distinct and more sustainable approach to stereochemical programming. This transformation diverts the enzyme from its native function in C–C bond formation by channeling the Breslow intermediate toward a homoenolate-mediated pathway, wherein specific noncovalent interactions stabilize the syn-periplanar geometry required for Z-selective dehalogenative elimination. Through rational active-site engineering, the stereochemical trajectory can be inverted to furnish the complementary E-isomer, enabling stereodivergent synthesis from a common scaffold. This work establishes a biocatalytic platform that addresses a critical gap in Z-alkene synthesis, expands the catalytic repertoire of ThDP-dependent enzymes, and provides a sustainable alternative to conventional methodologies.