@article{22141, abstract = {Molecular electrocatalysis is commonly interpreted through electronic descriptors, implicitly treating catalysts as mechanically passive during redox cycling. Yet, electron transfer often imposes structural demands on molecular scaffolds, raising the question of whether internal mechanical constraints can directly regulate access to reactive states and, in turn, catalytic outcomes. Addressing this question has remained challenging because mechanical effects are typically inseparable from changes in composition or electronic structure. Here, we achieve this separation by exploiting two constitutionally identical molecular catalysts whose only distinction is ligand geometry. This minimal geometric variation enables or suppresses intramolecular hydrogen bonding, thereby encoding distinct mechanical constraints that isolate molecular mechanics as a variable in redox accessibility. In the α isomer, molecular constraints impose a mechanically enforced barrier that severely limits access to the reactive redox state. This disrupts the temporal ordering of elementary steps, and diverts reactivity toward competing hydrogen evolution, eroding both selectivity and stability. In contrast, mechanical compliance in the β isomer enables facile access to the redox-active state, allowing CO2 activation to intrinsically outpace water activation and yielding CO selectivities exceeding 92%. Operando spectroscopy and real-time mass spectrometry, combined with computational simulation, directly resolve this mechanically gated reaction sequence as it unfolds. Molecular mechanics thus emerge as determinants that link electron flow to reaction sequencing and catalytic selectivity, revealing that constitutionally similar catalysts can be mechanically, and therefore catalytically, distinct.}, author = {Mendhe, Rahul Mahadeo and Christudas Dargily, Neethu and Kottaichamy, Alagar Raja and Dutt, Shifali and Sk, Mukaddar and Makri Nimbegondi Kotresh, Harish and Ottakam Thotiyl, Musthafa}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, publisher = {American Chemical Society}, title = {{Mechanical gating of redox access in molecular electrocatalysis}}, doi = {10.1021/jacs.6c02632}, year = {2026}, } @article{22645, abstract = {Nanocrystal superlattices are commonly formed by changing concentration, solvent conditions, or particle surface chemistry. Although effective, these approaches alter multiple contributions to the interparticle potential simultaneously, making it difficult to isolate the interactions responsible for ordering or to control assembly in chemically complex environments. Here, we show that oligomeric species present in a nanocrystal reaction medium drive superlattice formation through a depletion mechanism. Using PbTe nanocrystals as a model system, we identify Pb–oleate oligomers in the crude reaction mixture, characterize their solution structure, and quantify their contribution to the interparticle potential, establishing depletion as the dominant short-range interaction governing spontaneous body-centered cubic superlattice formation. We then confirm the depletion origin of ordering by showing that varying depletant concentration predictably shifts the order–disorder boundary and produces a thermally reversible transition between dispersed and ordered states ─ behavior that is inconsistent with van der Waals or ligand-mediated mechanisms but is a direct consequence of depletion control. Having established and validated the mechanism, we demonstrate that the same depletion framework can be deliberately activated in purified dispersions and transferred across nanocrystal systems of different composition and shape, including anisotropic and binary assemblies. These results establish precursor-derived depletion as a general and chemically grounded mechanism for nanocrystal superlattice formation, and show that collective ordering can be programmed through the surrounding medium rather than through particle surface modification.}, author = {Lee, Seungho and Balazs, Daniel and Rayaroth Puthiyaveettil, Aiswarya and Horta, Sharona and Goodrich, Carl Peter and Engel, Michael and Cherniukh, Ihor and Ibáñez, Maria}, issn = {1520-5126}, journal = {Journal of the AmericanChemical Society}, number = {29}, pages = {31245--31252}, publisher = {American Chemical Society}, title = {{Reaction medium asan architect of nanocrystal superlattices}}, doi = {10.1021/jacs.6c07859}, volume = {148}, year = {2026}, } @article{22638, abstract = {The one-bond proton-carbon coupling constant (1JCH) is an insightful probe of carbohydrate configuration. Equatorial and axial protons at the C1 position typically exhibit distinct 1JCH values, enabling NMR measurements to distinguish α- and β-configurations in carbohydrates. In principle, such measurements could provide insights into carbohydrates in the cell walls of intact microbes. However, traditionally, these measurements are performed by solution NMR with carbohydrates that were extracted, solubilized and fractionated, leaving the biological relevance of the measurements uncertain. Here, we demonstrate that 1H-detected solid-state NMR with fast magic-angle spinning allows quantitative measurements of 1JCH couplings for mobile capsular polysaccharides, directly on submilligram amounts of pathogenic cells. Our approach is demonstrated on intact cells of the pathogenic yeast Cryptococcus neoformans. High-resolution proton-detected spectra enabled the determination of coupling constants for five mobile polysaccharide units of the cryptococcal capsule, revealing their native configurations and confirming previous solution NMR-based anomeric configuration assignments.}, author = {Lends, Alons and Lamon, Gaelle and Vallet, Alicia and Grélard, Axelle and Morvan, Estelle and Aimanianda, Vishukumar and Schanda, Paul and Loquet, Antoine}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {27}, pages = {28037--28042}, publisher = {American Chemical Society}, title = {{On-cell detection of polysaccharide one-bond1Jch couplings by proton-detected solid-state NMR}}, doi = {10.1021/jacs.6c06064}, volume = {148}, year = {2026}, } @article{21432, abstract = {The interplay between symmetry and topology in magnetic materials makes it possible to engineer exotic phases and technologically useful properties. A key requirement for these pursuits is achieving control over local crystallographic and magnetic structure, usually through sample morphology (such as synthesis of bulk crystals versus thin films) and application of magnetic or electric fields. Here we show that V1/3NbS2 can be crystallized in two ordered superlattices, distinguished by the periodicity of out-of-plane magnetic intercalants. Whereas one of these structures is metallic and displays the hallmarks of altermagnetism, the other superlattice, which has not been isolated before in this family of intercalation compounds, is a semimetallic noncollinear antiferromagnet that may enable access to topologically nontrivial properties. This observation of an unconventional superlattice structure establishes a powerful route for tailoring the tremendous array of magnetic and electronic behaviors hosted in related materials and may expand their use in low-power spintronic or topological quantum devices.}, author = {Fender, Shannon S. and Schnitzer, Noah and Fang, Wuzhang and Bhatt, Lopa and Huang, Dingbin and Malik, Amani and Gonzalez, Oscar and Sunko, Veronika and Xie, Lilia S. and Muller, David A. and Orenstein, Joseph and Ping, Yuan and Goodge, Berit H. and Bediako, D. Kwabena}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {36}, pages = {32315--32320}, publisher = {American Chemical Society}, title = {{Unconventional superlattice ordering in intercalated transition metal dichalcogenide V1/3NbS2}}, doi = {10.1021/jacs.5c07385}, volume = {147}, year = {2025}, } @article{19072, abstract = {Pathogenic fungal and bacterial cells are enveloped within a cell wall, a molecular barrier at their cell surface, and a critical architecture that constantly evolves during pathogenesis. Understanding the molecular composition, structural organization, and mobility of polysaccharides constituting this cell envelope is crucial to correlate cell wall organization with its role in pathogenicity and to identify potential antifungal targets. For the fungal pathogen Cryptococcus neoformans, the characterization of the cell envelope has been complexified by the presence of an additional external polysaccharide capsular shell. Here, we investigate how magic-angle spinning (MAS) solid-state NMR techniques increase the analytical capabilities to characterize the structure and dynamics of this encapsulated pathogen. The versatility of proton detection experiments, dynamic-based filters, and relaxation measurements facilitate the discrimination of the highly mobile external capsular structure from the internal rigid cell wall of C. neoformans. In addition, we report the in situ detection of triglyceride molecules from lipid droplets based on NMR dynamic filters. Together, we demonstrate a nondestructive technique to study the cell wall architecture of encapsulated microbes using C. neoformans as a model, an airborne opportunistic fungal pathogen that infects mainly immunocompromised but also competent hosts.}, author = {Lends, Alons and Lamon, Gaelle and Delcourte, Loic and Sturny-Leclere, Aude and Grélard, Axelle and Morvan, Estelle and Abdul-Shukkoor, Muhammed Bilal and Berbon, Mélanie and Vallet, Alicia and Habenstein, Birgit and Dufourc, Erick J. and Schanda, Paul and Aimanianda, Vishukumar and Loquet, Antoine}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {8}, pages = {6813--6824}, publisher = {American Chemical Society}, title = {{Molecular distinction of cell wall and capsular polysaccharides in encapsulated pathogens by in situ magic-angle spinning NMR techniques}}, doi = {10.1021/jacs.4c16975}, volume = {147}, year = {2025}, } @article{19599, abstract = {Advances in nickel catalysis have significantly broadened the synthetic chemists’ toolbox, particularly through methodologies leveraging paramagnetic nickel species via photoredox catalysis or electrochemistry. Key to these reactions is the oxidation state modulation of nickel via single-electron transfer events. Recent mechanistic studies indicate that C(sp2)–heteroatom bond formations proceed through NiI/NiIII cycles. Related C(sp2)–C(sp3) cross-couplings operate via the photocatalytic generation of C-centered radicals and a catalytic cycle that involves Ni0, NiI, and NiIII species. Here, we show that light-mediated nickel-catalyzed C(sp2)–C(sp3) bond formations can be carried out without using exogenous photoredox catalysts but with a photoactive ligand. In a pursuit of expanding the scope of C(sp2)–heteroatom couplings using donor–acceptor ligands, we identified a photoactive nickel complex capable of catalyzing cross-couplings between aryl halides and benzyltrifluoroborate salts. Mechanistic investigations provide evidence that transmetalation between a photochemically generated NiI species and the organoboron compound is the key catalytic step in a NiI/NiIII catalytic cycle under these conditions.}, author = {Anghileri, Lucia and Baunis, Haralds and Bena, Aleksander and Giannoudis, Christos and Burke, John H. and Reischauer, Susanne and Merschjann, Christoph and Wallick, Rachel F. and Al Said, Tarek and Adams, Callum E and Simionato, Gianluca and Kovalenko, Sergey and Dell’Amico, Luca and Van Der Veen, Renske M. and Pieber, Bartholomäus}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {16}, pages = {13169–13179}, publisher = {American Chemical Society}, title = {{Evidence for a unifying NiI/NiIII mechanism in light-mediated cross-coupling catalysis}}, doi = {10.1021/jacs.4c16050}, volume = {147}, year = {2025}, } @article{19779, abstract = {The transverse thermoelectric (Nernst) effect is a powerful probe for studying the electronic and structural properties of materials. In this study, we employ transverse thermoelectric measurements to investigate the ferroelectric distortion in the topological crystalline insulator (TCI) Pb0.60Sn0.40Te, a compound derived from PbTe and SnTe, known for their exceptional thermoelectric performance and distinct ferroelectric properties. By leveraging Nernst measurements, we provide direct evidence of ferroelectric distortion in this TCI, corroborated by Shubnikov–de Haas quantum oscillations that confirm the presence of two topologically nontrivial Fermi pockets. Density functional theory calculations show that these pockets originate from the L and T points in the Brillouin zone of the distorted structure within the TCI phase. Raman spectroscopy further identifies a structural phase transition below 50 K, consistent with the quantum oscillation observations. This observation is further substantiated by temperature-dependent synchrotron X-ray pair distribution function analysis and transmission electron microscopy, which confirm the local off-centering of cations at low temperature. These findings underscore the potential of transverse thermoelectric measurements in unveiling ferroelectric distortions and their role in modulating topological quantum states, opening new directions for research into the synergy between ferroelectricity and topological phases.}, author = {Negi, Pranav and He, Bin and Ukolov, Denis and Horta, Sharona and Maji, Krishnendu and Mao, Ning and Peshcherenko, Nikolai and Yanda, Premakumar and Yao, Mengyu and Dutta, Moinak and Robredo, Iñigo and Iraola, Mikel and Vergniory, Maia G. and Lemmens, Peter and Zhang, Yang and Shekhar, Chandra and Ibáñez, Maria and Felser, Claudia and Roychowdhury, Subhajit}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {22}, pages = {18704--18711}, publisher = {American Chemical Society}, title = {{Evidence of ferroelectric distortions in topological crystalline insulators via transverse thermoelectric measurements}}, doi = {10.1021/jacs.5c01700}, volume = {147}, year = {2025}, } @article{20010, abstract = {Chirality-induced spin selectivity (CISS), which refers to the ability of chiral molecules to preferentially select spins during electron transfer, has attracted great attention during the past two decades. However, the theoretical and experimental understanding of the CISS effect remains preliminary. In this study, we demonstrate that there is no distinguishable CISS effect in the case of coherent electron transport through single chiral molecular junctions for a set of four molecule studied here. Our conclusion is based on statistical evaluations of thousands of single-molecule junctions across four different molecules with different origins of chirality measured by the scanning tunneling microscope-based break-junction technique. The experimental results for all molecules show no dependence on external magnetic field or chirality in both conductance and current–voltage measurements. In addition, ab initio Hartree-Fork calculations combined with the nonequilibrium Green’s function method reveal that the spin–orbit coupling within chiral junctions bound to a few gold atoms is generally too weak to induce detectable spin polarizations from spin flipping or spin filtering during the ultrafast electron-transport time scale. The absence of an observable CISS effect in the coherent electron-transport regime suggests that the effect may only be found in other electron-transfer regimes and requires further experimental and theoretical efforts to achieve a comprehensive understanding.}, author = {Li, Liang and Shi, Wanzhuo and Mahajan, Ankit and Zhang, Junxiang and Gómez-Gómez, Marta and Labella, Jorge and Louie, Shayan and Torres, Tomás and Barlow, Stephen and Marder, Seth R. and Reichman, David R. and Venkataraman, Latha}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {28}, pages = {25043--25051}, publisher = {American Chemical Society}, title = {{Too fast for spin flipping: Absence of chirality-induced spin selectivity in coherent electron transport through single-molecule junctions}}, doi = {10.1021/jacs.5c08517}, volume = {147}, year = {2025}, } @article{20321, abstract = {Microsecond-to-millisecond motions are instrumental for many biomolecular functions, including enzymatic activity and ligand binding. Bloch-McConnell Relaxation Dispersion (BMRD) Nuclear Magnetic Resonance (NMR) spectroscopy is a key technique for studying these dynamic processes. While BMRD experiments are routinely used to probe protein motions in solution, the experiment is more demanding in the solid state, where dipolar couplings complicate the spin dynamics. It is believed that high deuteration levels are required and sufficient to obtain accurate and quantitative data. Here we show that even under fast magic-angle spinning and high levels of deuteration artifactual “bumps” in 15N R1ρ BMRD profiles are common. The origin of these artifacts is identified as a second-order three-spin Mixed Rotational and Rotary Resonance (MIRROR) recoupling condition. These artifacts are found to be a significant confounding factor for the accurate quantification of microsecond protein dynamics using BMRD in the solid state. We show that the application of low-power continuous wave (CW) decoupling simultaneously with the 15N spin-lock leads to the suppression of these conditions and enables quantitative measurements of microsecond exchange in the solid state. Remarkably, the application of decoupling allows the measurement of accurate BMRD even in fully protonated proteins at 100 kHz MAS, thus extending the scope of μs dynamics measurements in MAS NMR.}, author = {Tatman, Benjamin and Sridharan, Vidhyalakshmi and Uttarkabat, Motilal and Jaroniec, Christopher P. and Ernst, Matthias and Rovo, Petra and Schanda, Paul}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {32}, pages = {29315--29326}, publisher = {American Chemical Society}, title = {{Bumps on the road: The way to clean relaxation dispersion magic-angle spinning NMR}}, doi = {10.1021/jacs.5c09057}, volume = {147}, year = {2025}, } @article{20326, abstract = {Ag2Se is a promising n-type thermoelectric material, but its performance is limited by excessive carrier concentration, compositional inhomogeneity, and phase instability, challenges rooted in a narrow homogeneity range and uncontrolled Ag+ diffusion in the superionic phase. Here, we address these issues by exploiting liquid–solid interface reactions using CdSe complexes that remove surface excess Ag to yield stoichiometric Ag2Se and generate CdSe nanodomains that inhibit Ag+ diffusion and constrain grain growth. The resulting Ag2Se-CdSe nanocomposites exhibit a reproducible, stable figure of merit (zT) of 1.04 between 300 and 390 K. Beyond demonstrating high performance, we elucidate the interfacial chemical reactions that give rise to the observed microstructure and transport properties, providing a foundation for rationally engineering interfacial chemistry to tailor transport properties across diverse thermoelectric material systems.}, author = {Liu, Yu and Kleinhanns, Tobias and Horta, Sharona and Dutkiewicz, Ewelina and Lu, Shaoqing and Spadaro, Maria Chiara and Genç, Aziz and Chen, Lei and Lim, Khak Ho and Hong, Min and Arbiol, Jordi and Ibáñez, Maria}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {35}, pages = {32199--32208}, publisher = {American Chemical Society}, title = {{Liquid-solid interface reactions drive enhanced thermoelectric performance in Ag2Se}}, doi = {10.1021/jacs.5c11435}, volume = {147}, year = {2025}, } @article{20961, abstract = {Self-replicating molecules and well-defined folded macromolecules are of great significance in the emergence and evolution of life. How they may interconnect and affect each other remains largely elusive. Here, we demonstrate an abiotic system where a single building block can oligomerize to yield either a self-replicating molecule or a foldamer. Specifically, agitation of a disulfide-based dynamic combinatorial library at moderately elevated pH channels it selectively into a self-replicating hexamer assembled into fibers, after passing through a period where a 15-subunit macrocyclic foldamer existed transiently. Without mechanoagitation or at lower pH, the formation of hexamer fiber is suppressed, resulting in the accumulation of the 15mer foldamer. Foldamer and self-replicator can be interconverted in response to external stimuli, including agitation and a change in pH. Furthermore, upon the addition of a photoacid, the pH of the medium can be controlled by irradiation, driving the switching between replicator and foldamer and allowing a dissipative out-of-equilibrium state to be accessed, using light as a source of energy.}, author = {Jin, Yulong and Mandal, Pradeep K and Wu, Juntian and Kiani, Armin and Zhao, Rui and Huc, Ivan and Otto, Sijbren}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {49}, pages = {33395--33402}, publisher = {American Chemical Society}, title = {{Light-mediated interconversion between a foldamer and a self-replicator}}, doi = {10.1021/jacs.4c09114}, volume = {146}, year = {2024}, } @article{20962, abstract = {Systems chemistry has emerged as a useful paradigm to access structures and phenomena typically exhibited by living systems, including complex molecular systems such as self-replicators and foldamers. As we progress further toward the noncovalent synthesis of life-like systems, and eventually life itself, it is necessary to gain control over assembly pathways. Dissipative chemical fueling has enabled access to stable populations of (self-assembled) structures that would normally form only transiently. Here, we report a synthetic dynamic combinatorial library, made from a single structurally simple building block, from which a self-replicator and a foldamer can emerge along two distinct and competing pathways through an inter- or intramolecular assembly process, respectively. A fueled chemical reaction cycle is then set up to generate the foldamer transiently, in the presence of the self-replicator. The partitioning of the building block between the folding and self-replication pathways and the duration of the fueled reaction cycles are controlled by adjusting the amount of the chemical fuel. An out-of-equilibrium steady state involving the two assemblies could also be achieved by using a continuous stirred tank reactor with inflow and outflow of material. This work connects the domains of folding and self-replication in synthetic systems through dissipative out-of-equilibrium chemistry. It demonstrates that foldamers and self-replicators, formed from the same building block, can stably coexist if the system is continuously supplied with energy, while at equilibrium, the Gibbs phase rule prohibits such coexistence.}, author = {Sood, Ankush and Mandal, Pradeep K and Ottelé, Jim and Wu, Juntian and Eleveld, Marcel and Hatai, Joydev and Pappas, Charalampos G. and Huc, Ivan and Otto, Sijbren}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, keywords = {Fibers, Foldamers, Macrocycles, Monomers, Peptides, Proteins}, number = {49}, pages = {33386--33394}, publisher = {American Chemical Society}, title = {{Simultaneous formation of a foldamer and a self-replicator by out-of-equilibrium dynamic covalent chemistry}}, doi = {10.1021/jacs.4c09111}, volume = {146}, year = {2024}, } @article{20529, abstract = {Single molecules bridging two metallic electrodes can emit light through electroluminescence when subjected to a bias voltage. Typically, light emission in such devices results from transitions between molecular states, although in the presence of light-matter coupling, the emission can result from a transition between hybrid light-matter states. Here, we create single metal-molecule-metal junctions and simultaneously collect conductance and electroluminescence data using a scanning tunneling microscope (STM) equipped with a custom spectrometer. Through experimental analysis and electronic structure calculations, we provide evidence for a molecule-electrode interfacial exciton coupled to a junction cavity plasmon. Importantly, we find that close to resonant transport conditions, the molecular junction functions as a single emitter that is strongly coupled to the junction cavity mode, leading to characteristic Rabi splitting of the emission spectrum and providing the first example of an electroluminescence-driven single-molecule system in the regime of strong light-matter coupling.}, author = {Paoletta, Angela L. and Hoffmann, Norah M. and Cheng, Daniel W. and York, Emma and Xu, Ding and Zhang, Boyuan and Delor, Milan and Berkelbach, Timothy C. and Venkataraman, Latha}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {50}, pages = {34394--34400}, publisher = {American Chemical Society}, title = {{Plasmon-exciton strong coupling in single-molecule junction electroluminescence}}, doi = {10.1021/jacs.4c09782}, volume = {146}, year = {2024}, } @article{17853, abstract = {Single-molecule one-dimensional topological insulator (1D TI) is a class of molecular wires that exhibit increasing conductance with wire length. This unique trend is due to the coupling between the two low-lying topological edge states of 1D TIs described by the Su–Schrieffer–Heeger model. In principle, this quantum phenomenon within 1D TIs can be utilized to achieve long-range gating in molecular conductors. Here, we study electron transport through a single-edge state of doubly oxidized oligophenylene bis(triarylamine) to understand the effect of the edge state coupling on conductance. We find that conductance is elevated by approximately 1 order of magnitude compared to a control molecule with the same conductance pathway. Density function theory calculations further support that the increase in conductance is due to the interaction between the edge states of 1D TIs. This work demonstrates a new gating paradigm in molecular electronics, while also providing a deeper understanding of how edge states interact and affect electron transport within 1D TIs.}, author = {Li, Liang and Louie, Shayan and Orchanian, Nicholas M. and Nuckolls, Colin and Venkataraman, Latha}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {24}, pages = {16920--16925}, publisher = {American Chemical Society}, title = {{Long-range gating in single-molecule one-dimensional topological insulators}}, doi = {10.1021/jacs.4c05699}, volume = {146}, year = {2024}, } @article{17856, abstract = {The successful incorporation of molecules as active circuit elements relies on the ability to tune their electronic properties through chemical design. A synthetic strategy that has been used to manipulate and gate circuit conductance involves attaching a pendant substituent along the molecular conduction pathway. However, such a chemical gate has not yet been shown to significantly modify conductance. Here, we report a novel series of triarylmethylium and triangulenium carbocations gated by different substituents coupled to the delocalized conducting orbitals on the molecular backbone through a Fano resonance. By changing the pendant substituents to modulate the position of the Fano resonance and its coupling to the conducting orbitals, we can regulate the junction conductance by a remarkable factor of 450. This work thus provides a new design principle to enable effective chemical gating of single-molecule devices toward effective molecular transistors.}, author = {Prindle, Claudia R. and Shi, Wanzhuo and Li, Liang and Dahl Jensen, Jesper and Laursen, Bo W. and Steigerwald, Michael L. and Nuckolls, Colin and Venkataraman, Latha}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {6}, pages = {3646--3650}, publisher = {American Chemical Society}, title = {{Effective gating in single-molecule junctions through fano resonances}}, doi = {10.1021/jacs.3c14226}, volume = {146}, year = {2024}, } @article{13095, abstract = {Disulfide bond formation is fundamentally important for protein structure and constitutes a key mechanism by which cells regulate the intracellular oxidation state. Peroxiredoxins (PRDXs) eliminate reactive oxygen species such as hydrogen peroxide through a catalytic cycle of Cys oxidation and reduction. Additionally, upon Cys oxidation PRDXs undergo extensive conformational rearrangements that may underlie their presently structurally poorly defined functions as molecular chaperones. Rearrangements include high molecular-weight oligomerization, the dynamics of which are, however, poorly understood, as is the impact of disulfide bond formation on these properties. Here we show that formation of disulfide bonds along the catalytic cycle induces extensive μs time scale dynamics, as monitored by magic-angle spinning NMR of the 216 kDa-large Tsa1 decameric assembly and solution-NMR of a designed dimeric mutant. We ascribe the conformational dynamics to structural frustration, resulting from conflicts between the disulfide-constrained reduction of mobility and the desire to fulfill other favorable contacts.}, author = {Troussicot, Laura and Vallet, Alicia and Molin, Mikael and Burmann, Björn M. and Schanda, Paul}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {19}, pages = {10700–10711}, publisher = {American Chemical Society}, title = {{Disulfide-bond-induced structural frustration and dynamic disorder in a peroxiredoxin from MAS NMR}}, doi = {10.1021/jacs.3c01200}, volume = {145}, year = {2023}, } @article{13354, abstract = {Integrating light-sensitive molecules within nanoparticle (NP) assemblies is an attractive approach to fabricate new photoresponsive nanomaterials. Here, we describe the concept of photocleavable anionic glue (PAG): small trianions capable of mediating interactions between (and inducing the aggregation of) cationic NPs by means of electrostatic interactions. Exposure to light converts PAGs into dianionic products incapable of maintaining the NPs in an assembled state, resulting in light-triggered disassembly of NP aggregates. To demonstrate the proof-of-concept, we work with an organic PAG incorporating the UV-cleavable o-nitrobenzyl moiety and an inorganic PAG, the photosensitive trioxalatocobaltate(III) complex, which absorbs light across the entire visible spectrum. Both PAGs were used to prepare either amorphous NP assemblies or regular superlattices with a long-range NP order. These NP aggregates disassembled rapidly upon light exposure for a specific time, which could be tuned by the incident light wavelength or the amount of PAG used. Selective excitation of the inorganic PAG in a system combining the two PAGs results in a photodecomposition product that deactivates the organic PAG, enabling nontrivial disassembly profiles under a single type of external stimulus.}, author = {Wang, Jinhua and Peled, Tzuf Shay and Klajn, Rafal}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, keywords = {Colloid and Surface Chemistry, Biochemistry, General Chemistry, Catalysis}, number = {7}, pages = {4098--4108}, publisher = {American Chemical Society}, title = {{Photocleavable anionic glues for light-responsive nanoparticle aggregates}}, doi = {10.1021/jacs.2c11973}, volume = {145}, year = {2023}, } @article{20970, abstract = {Dynamic foldamers are synthetic folded molecules which can change their conformation in response to an external stimulus and are currently at the forefront of foldamer chemistry. However, constitutionally dynamic foldamers, which can change not only their conformation but also their molecular constitution in response to their environment, are without precedent. We now report a size- and shape-switching small dynamic covalent foldamer network which responds to changes in pH. Specifically, acidic conditions direct the oligomerization of a dipeptide-based building block into a 16-subunit macrocycle with well-defined conformation and with high selectivity. At higher pH the same building block yields another cyclic foldamer with a smaller ring size (9mer). The two foldamers readily and repeatedly interconvert upon adjustment of the pH of the solution. We have previously shown that addition of a template can direct oligomerization of the same building block to yet other rings sizes (including a 12mer and a 13mer, accompanied by a minor amount of 14mer). This brings the total number of discrete foldamers that can be accessed from a single building block to five. For a single building block system to exhibit such highly diverse structure space is unique and sets this system of foldamers apart from proteins. Furthermore, the emergence of constitutional dynamicity opens up new avenues to foldamers with adaptive behavior.}, author = {Jin, Yulong and Mandal, Pradeep K and Wu, Juntian and Böcher, Niklas and Huc, Ivan and Otto, Sijbren}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {5}, pages = {2822--2829}, publisher = {American Chemical Society}, title = {{(Re-)directing oligomerization of a single building block into two specific dynamic covalent foldamers through pH}}, doi = {10.1021/jacs.2c09325}, volume = {145}, year = {2023}, } @article{14664, abstract = {The architecture of self-assembled host molecules can profoundly affect the properties of the encapsulated guests. For example, a rigid cage with small windows can efficiently protect its contents from the environment; in contrast, tube-shaped, flexible hosts with large openings and an easily accessible cavity are ideally suited for catalysis. Here, we report a “Janus” nature of a Pd6L4 coordination host previously reported to exist exclusively as a tube isomer (T). We show that upon encapsulating various tetrahedrally shaped guests, T can reconfigure into a cage-shaped host (C) in quantitative yield. Extracting the guest affords empty C, which is metastable and spontaneously relaxes to T, and the T⇄C interconversion can be repeated for multiple cycles. Reversible toggling between two vastly different isomers paves the way toward controlling functional properties of coordination hosts “on demand”.}, author = {Hema, Kuntrapakam and Grommet, Angela B. and Białek, Michał J. and Wang, Jinhua and Schneider, Laura and Drechsler, Christoph and Yanshyna, Oksana and Diskin-Posner, Yael and Clever, Guido H. and Klajn, Rafal}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {45}, pages = {24755--24764}, publisher = {American Chemical Society}, title = {{Guest encapsulation alters the thermodynamic landscape of a coordination host}}, doi = {10.1021/jacs.3c08666}, volume = {145}, year = {2023}, } @article{17860, abstract = {Radicals are unique molecular systems for applications in electronic devices due to their open-shell electronic structures. Radicals can function as good electrical conductors and switches in molecular circuits while also holding great promise in the field of molecular spintronics. However, it is both challenging to create stable, persistent radicals and to understand their properties in molecular junctions. The goal of this Perspective is to address this dual challenge by providing design principles for the synthesis of stable radicals relevant to molecular junctions, as well as offering current insight into the electronic properties of radicals in single-molecule devices. By exploring both the chemical and physical properties of established radical systems, we will facilitate increased exploration and development of radical-based molecular systems.}, author = {Li, Liang and Prindle, Claudia R. and Shi, Wanzhuo and Nuckolls, Colin and Venkataraman, Latha}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {33}, pages = {18182--18204}, publisher = {American Chemical Society}, title = {{Radical single-molecule junctions}}, doi = {10.1021/jacs.3c04487}, volume = {145}, year = {2023}, }