Juana Goulart Stollmaier, Briana Abigail R. Czarnecki, David W. Christianson
Organoselenocyanates have attracted considerable attention in recent years due to their therapeutic potential and versatility in medicinal chemistry. Here, we report on the mechanism of inhibition by 5-phenylcarbamoylpentyl selenocyanide (SelSA-2), an analogue of the well-characterized histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA, a.k.a. Vorinostat). We show that histone deacetylases 6 and 10 promote selenocyanate hydrolysis to generate a selenolate anion, and we explore the redox chemistry of selenium as it modulates inhibitory activity through reversible formation of the diselenide. The 2.15 Å-resolution crystal structure of histone deacetylase 6 cocrystallized with SelSA-2 conclusively demonstrates that it is not the selenocyanate, but instead a zinc-bound selenolate anion, that is the active pharmacophore responsible for enzyme inhibition.
{"title":"Mechanism-Based Inhibition of Histone Deacetylase 6 by a Selenocyanate Is Subject to Redox Modulation","authors":"Juana Goulart Stollmaier, Briana Abigail R. Czarnecki, David W. Christianson","doi":"10.1021/jacs.5c00157","DOIUrl":"https://doi.org/10.1021/jacs.5c00157","url":null,"abstract":"Organoselenocyanates have attracted considerable attention in recent years due to their therapeutic potential and versatility in medicinal chemistry. Here, we report on the mechanism of inhibition by 5-phenylcarbamoylpentyl selenocyanide (SelSA-2), an analogue of the well-characterized histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA, a.k.a. Vorinostat). We show that histone deacetylases 6 and 10 promote selenocyanate hydrolysis to generate a selenolate anion, and we explore the redox chemistry of selenium as it modulates inhibitory activity through reversible formation of the diselenide. The 2.15 Å-resolution crystal structure of histone deacetylase 6 cocrystallized with SelSA-2 conclusively demonstrates that it is not the selenocyanate, but instead a zinc-bound selenolate anion, that is the active pharmacophore responsible for enzyme inhibition.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"80 1 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yubin He, Rui Zhang, Peichao Zou, Ryan Wonu Chu, Ruoqian Lin, Kang Xu, Huolin L. Xin
The integration of water-based electrolytes into zinc-ion batteries encounters challenges due to the limited voltage window of water, interfacial side reactions of mobile counterions, and the growth of zinc metal (Zn0) dendrites during charge. In this study, we introduce a nonfluorinated, cation-conducting polyelectrolyte membrane (PEM) designed to alleviate these challenges by suppressing the reactivities of both water and counterions. This PEM forms hydrogen bonds with water molecules through its proton-accepting side chains, thus shifting the lowest unoccupied molecular orbital (LUMO) energy of water from −0.37 to −0.14 eV and inducing a negative shift in the onset potential for hydrogen evolution by 110 mV. Additionally, it immobilizes the counteranions onto the polymer backbones via covalent bonding, hence making the Zn2+ transference number nearly unity (0.96). Meanwhile, the high modulus PEM establishes a solid-state diffusion barrier to homogenize the interfacial Zn2+ flux, leading to 3D in-plane interfacial Zn2+ diffusion and compact Zn0 plating within the (002) plane. Atomic resolution scanning transmission electron microscopy (STEM) reveals corrosion-free Zn0 deposition without electrolyte degradation, while operando transition X-ray microscopy (TXM) further illustrates the real-time dendrite-free Zn0 plating process at 5 mA/cm2. Consequently, the unique properties of this water-binding and anion-tethering PEM enable enhanced electrochemical performance without employing highly fluorinated and expensive anions. This PEM demonstrates a durability of 3800 h in Zn0–Zn0 symmetric cells and a lifetime of 6000 cycles in Zn0–LiV3O8 full cells.
{"title":"Polyelectrolyte Membrane Enables Highly Reversible Zinc Battery Chemistry via Immobilizing Anion and Stabilizing Water","authors":"Yubin He, Rui Zhang, Peichao Zou, Ryan Wonu Chu, Ruoqian Lin, Kang Xu, Huolin L. Xin","doi":"10.1021/jacs.4c12409","DOIUrl":"https://doi.org/10.1021/jacs.4c12409","url":null,"abstract":"The integration of water-based electrolytes into zinc-ion batteries encounters challenges due to the limited voltage window of water, interfacial side reactions of mobile counterions, and the growth of zinc metal (Zn<sup>0</sup>) dendrites during charge. In this study, we introduce a nonfluorinated, cation-conducting polyelectrolyte membrane (PEM) designed to alleviate these challenges by suppressing the reactivities of both water and counterions. This PEM forms hydrogen bonds with water molecules through its proton-accepting side chains, thus shifting the lowest unoccupied molecular orbital (LUMO) energy of water from −0.37 to −0.14 eV and inducing a negative shift in the onset potential for hydrogen evolution by 110 mV. Additionally, it immobilizes the counteranions onto the polymer backbones via covalent bonding, hence making the Zn<sup>2+</sup> transference number nearly unity (0.96). Meanwhile, the high modulus PEM establishes a solid-state diffusion barrier to homogenize the interfacial Zn<sup>2+</sup> flux, leading to 3D in-plane interfacial Zn<sup>2+</sup> diffusion and compact Zn<sup>0</sup> plating within the (002) plane. Atomic resolution scanning transmission electron microscopy (STEM) reveals corrosion-free Zn<sup>0</sup> deposition without electrolyte degradation, while operando transition X-ray microscopy (TXM) further illustrates the real-time dendrite-free Zn<sup>0</sup> plating process at 5 mA/cm<sup>2</sup>. Consequently, the unique properties of this water-binding and anion-tethering PEM enable enhanced electrochemical performance without employing highly fluorinated and expensive anions. This PEM demonstrates a durability of 3800 h in Zn<sup>0</sup>–Zn<sup>0</sup> symmetric cells and a lifetime of 6000 cycles in Zn<sup>0</sup>–LiV<sub>3</sub>O<sub>8</sub> full cells.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"13 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
1,2-Amino-difunctionalization reactions of alkenes allow the efficient introduction of different functional groups and the rapid construction of valuable functionalized amines. In this respect, we report a copper-catalyzed 1,2-amino-alkoxycarbonylation of unactivated alkenes with CO and alkylamine precursors in the presence of a Lewis acid additive. The novel protocol allows direct access to valuable β-amino acid derivatives from easily available starting materials. The presented methods feature high chemo- and regioselectivities, good functional group tolerance, and substrate scope including diverse bioactive compounds and drug-like molecules. Mechanistic studies indicate that the Lewis acid additive is the key to realizing the efficient umpolung addition of nucleophilic aminyl radicals to electron-rich alkenes, which represents an elegant activation strategy for aminyl radicals.
{"title":"Copper-Catalyzed Selective Amino-alkoxycarbonylation of Unactivated Alkenes with CO","authors":"Si-Shun Yan, Ralf Jackstell, Matthias Beller","doi":"10.1021/jacs.4c13723","DOIUrl":"https://doi.org/10.1021/jacs.4c13723","url":null,"abstract":"1,2-Amino-difunctionalization reactions of alkenes allow the efficient introduction of different functional groups and the rapid construction of valuable functionalized amines. In this respect, we report a copper-catalyzed 1,2-amino-alkoxycarbonylation of unactivated alkenes with CO and alkylamine precursors in the presence of a Lewis acid additive. The novel protocol allows direct access to valuable β-amino acid derivatives from easily available starting materials. The presented methods feature high chemo- and regioselectivities, good functional group tolerance, and substrate scope including diverse bioactive compounds and drug-like molecules. Mechanistic studies indicate that the Lewis acid additive is the key to realizing the efficient umpolung addition of nucleophilic aminyl radicals to electron-rich alkenes, which represents an elegant activation strategy for aminyl radicals.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"45 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soonho Kwon, Prabhat Prakash, Yixiang Cao, Frances A. Houle, William A. Goddard III
The recombination of water ions has diverse scientific and practical implications, ranging from acid–base chemistry and biological systems to planetary environments and applications in fuel cell and carbon conversion technologies. While spatial confinement affects the physicochemical properties of water dynamics, its impact on the recombination process has rarely been studied. In this work, we investigate the dynamics of water, the water ion distribution, and the ion recombination process in water droplets as a function of droplet size through molecular dynamics simulations and adaptive quantum mechanical/molecular mechanical calculations. We compare the dynamics of recombination in water droplet sizes ranging from 100 to 18 000 waters, both in their interiors and on their surfaces. We found that the self-diffusion of water dramatically decreases in droplets with a diameter below 2.2 nm. Using a classical RexPoN force-field, we found that the ions in 1000 H2O’s spend almost 50% of the time on the surface and 0.5 nm beneath it with a slight preference for OH– ion to reside longer on the surface. We estimate that, on average, recombination in these drops occurs at 400 ps in 1000 H2O’s and 1 ns in 3000 H2O’s. We also found that recombination is not limited by the local structure of the surface or the size of the droplet but can be influenced by the geometry of the water wire connecting the ions as they approach each other, which can often prevent recombination. Our results provide insights to the reaction microenvironments presented by nanoscopic water droplets.
{"title":"Recombination of Autodissociated Water Ions in a Nanoscale Pure Water Droplet","authors":"Soonho Kwon, Prabhat Prakash, Yixiang Cao, Frances A. Houle, William A. Goddard III","doi":"10.1021/jacs.4c15103","DOIUrl":"https://doi.org/10.1021/jacs.4c15103","url":null,"abstract":"The recombination of water ions has diverse scientific and practical implications, ranging from acid–base chemistry and biological systems to planetary environments and applications in fuel cell and carbon conversion technologies. While spatial confinement affects the physicochemical properties of water dynamics, its impact on the recombination process has rarely been studied. In this work, we investigate the dynamics of water, the water ion distribution, and the ion recombination process in water droplets as a function of droplet size through molecular dynamics simulations and adaptive quantum mechanical/molecular mechanical calculations. We compare the dynamics of recombination in water droplet sizes ranging from 100 to 18 000 waters, both in their interiors and on their surfaces. We found that the self-diffusion of water dramatically decreases in droplets with a diameter below 2.2 nm. Using a classical RexPoN force-field, we found that the ions in 1000 H<sub>2</sub>O’s spend almost 50% of the time on the surface and 0.5 nm beneath it with a slight preference for OH<sup>–</sup> ion to reside longer on the surface. We estimate that, on average, recombination in these drops occurs at 400 ps in 1000 H<sub>2</sub>O’s and 1 ns in 3000 H<sub>2</sub>O’s. We also found that recombination is not limited by the local structure of the surface or the size of the droplet but can be influenced by the geometry of the water wire connecting the ions as they approach each other, which can often prevent recombination. Our results provide insights to the reaction microenvironments presented by nanoscopic water droplets.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"85 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wyatt C. Powell, Ruiheng Jing, Morgane Herlory, Patrick Holland, Darya Poliyenko, Christopher C. Ebmeier, Michael H. B. Stowell, Maciej A. Walczak
Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the accumulation of tau protein aggregates. In this study, we investigated the effects of N-glycosylation on tau, focusing on its impact on aggregation and phase behavior. We chemically prepared homogeneous glycoproteins with high-mannose glycans or a single N-acetylglucosamine at the confirmed glycosylation sites in K18 and 2N4R tau. Our findings reveal that N-glycosylation significantly alters biophysical properties and potentially cellular functions of tau. Small glycans promote tau aggregation and liquid–liquid phase separation (LLPS), while larger glycans reduce these effects. High mannose glycans at N410 enhance phosphorylation by GSK3β, suggesting a pathological role in AD. Functional assays demonstrate that N-glycosylation does not impact microtubule polymerization dynamics but modulates aggregation kinetics and morphology. This research underscores the importance of glycosylation in tau pathology and opens new avenues for therapeutic interventions targeting glycan processing.
{"title":"Chemical Synthesis Reveals Pathogenic Role of N-Glycosylation in Microtubule-Associated Protein Tau","authors":"Wyatt C. Powell, Ruiheng Jing, Morgane Herlory, Patrick Holland, Darya Poliyenko, Christopher C. Ebmeier, Michael H. B. Stowell, Maciej A. Walczak","doi":"10.1021/jacs.4c17873","DOIUrl":"https://doi.org/10.1021/jacs.4c17873","url":null,"abstract":"Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the accumulation of tau protein aggregates. In this study, we investigated the effects of <i>N</i>-glycosylation on tau, focusing on its impact on aggregation and phase behavior. We chemically prepared homogeneous glycoproteins with high-mannose glycans or a single <i>N</i>-acetylglucosamine at the confirmed glycosylation sites in K18 and 2N4R tau. Our findings reveal that <i>N</i>-glycosylation significantly alters biophysical properties and potentially cellular functions of tau. Small glycans promote tau aggregation and liquid–liquid phase separation (LLPS), while larger glycans reduce these effects. High mannose glycans at N410 enhance phosphorylation by GSK3β, suggesting a pathological role in AD. Functional assays demonstrate that <i>N</i>-glycosylation does not impact microtubule polymerization dynamics but modulates aggregation kinetics and morphology. This research underscores the importance of glycosylation in tau pathology and opens new avenues for therapeutic interventions targeting glycan processing.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"49 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joseph J. Gair, Mayuko Isomura, Corin C. Wagen, Daniel A. Strassfeld, Eric N. Jacobsen
We report the highly enantioselective ring-opening of 3-substituted azetidines by alkyl and acyl halides promoted by a chiral squaramide hydrogen-bond donor catalyst. Broad scope is achieved across a variety of substrate combinations possessing disparate steric features. The same catalyst had been identified previously to promote enantioselective opening of oxetanes via both Lewis and Brønsted acid mechanisms. This remarkable generality is interpreted to arise from catalyst recognition of the conserved electrostatic features of the dipolar enantioselectivity-determining transition states in the ring-opening SN2 mechanisms with simultaneous tolerance of variation of the specific functional group and steric features of the reactions. Specific experimental and computational evidence is provided for a network of electrostatic interactions that forms a shared basis for enantioinduction across these transformations. This work provides a framework for designing catalysts that achieve high enantioselectivity across diverse reactions unified by conserved polar mechanisms.
{"title":"Enantioselective Ring Opening of Azetidines via Charge Recognition in Hydrogen-Bond-Donor Catalysis","authors":"Joseph J. Gair, Mayuko Isomura, Corin C. Wagen, Daniel A. Strassfeld, Eric N. Jacobsen","doi":"10.1021/jacs.5c00165","DOIUrl":"https://doi.org/10.1021/jacs.5c00165","url":null,"abstract":"We report the highly enantioselective ring-opening of 3-substituted azetidines by alkyl and acyl halides promoted by a chiral squaramide hydrogen-bond donor catalyst. Broad scope is achieved across a variety of substrate combinations possessing disparate steric features. The same catalyst had been identified previously to promote enantioselective opening of oxetanes via both Lewis and Brønsted acid mechanisms. This remarkable generality is interpreted to arise from catalyst recognition of the conserved electrostatic features of the dipolar enantioselectivity-determining transition states in the ring-opening S<sub>N</sub>2 mechanisms with simultaneous tolerance of variation of the specific functional group and steric features of the reactions. Specific experimental and computational evidence is provided for a network of electrostatic interactions that forms a shared basis for enantioinduction across these transformations. This work provides a framework for designing catalysts that achieve high enantioselectivity across diverse reactions unified by conserved polar mechanisms.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"22 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jonas Jacobs, Andy Bivour, Vadim Sikolenko, Holger Kohlmann, Thomas C. Hansen, James R. Hester, Ke Xu, Jörn Schmedt auf der Günne, Stefan G. Ebbinghaus
Ruddlesden–Popper oxyfluorides exhibit unique properties, but their synthesis is often hindered by low thermodynamic stability. To overcome this challenge, understanding the formation mechanism of these materials is crucial for optimizing the reaction conditions and accessing new products. This study presents an in-depth investigation of the fluorination reaction of La2NiO4 with poly(vinylidene fluoride) (PVDF), targeting the oxyfluorides La2NiO3F2 and La2NiO2.5F3, which exhibit distinct structural distortions. In situ X-ray diffraction experiments, performed on a laboratory diffractometer, revealed the presence of four distinct reaction intermediates. The crystal structures of these intermediates were further elucidated through X-ray and neutron powder diffraction experiments, complemented by in situ neutron powder diffraction data obtained using a setup featuring a low-background cell made from single-crystalline sapphire. 19F MAS NMR spectroscopy was employed to localize the fluoride ions and to track the consumption of PVDF. By systematically optimizing reaction conditions, we successfully obtained both oxyfluorides and quantified the phase evolution of all intermediates through extensive Rietveld refinements, yielding the following reaction steps: La2NiO4 (I4/mmm) → Inter#1 (Fmmm) → Inter#2 (Fmmm, with increased orthorhombic distortion) → Inter#3 (C2/c) → La2NiO3F2 (Cccm). In the presence of 50% excess PVDF, La2NiO3F2 is not obtained from Inter#3 and the reaction instead progresses via Inter#4 (P42/nnm) to La2NiO2.5F3 (P42/nnm, with a larger unit cell). This study demonstrates the power of laboratory in situ XRD experiments in elucidating complex fluorination reaction mechanisms, enabling the synthesis of new oxyfluorides with interesting physical properties. The in situ approach represents a significant advancement over traditional trial-and-error methods, which are still prevalent in solid-state synthesis.
{"title":"Unveiling the Fluorination Pathway of Ruddlesden–Popper Oxyfluorides: A Comprehensive in Situ X-ray and Neutron Diffraction Study","authors":"Jonas Jacobs, Andy Bivour, Vadim Sikolenko, Holger Kohlmann, Thomas C. Hansen, James R. Hester, Ke Xu, Jörn Schmedt auf der Günne, Stefan G. Ebbinghaus","doi":"10.1021/jacs.4c18187","DOIUrl":"https://doi.org/10.1021/jacs.4c18187","url":null,"abstract":"Ruddlesden–Popper oxyfluorides exhibit unique properties, but their synthesis is often hindered by low thermodynamic stability. To overcome this challenge, understanding the formation mechanism of these materials is crucial for optimizing the reaction conditions and accessing new products. This study presents an in-depth investigation of the fluorination reaction of La<sub>2</sub>NiO<sub>4</sub> with poly(vinylidene fluoride) (PVDF), targeting the oxyfluorides La<sub>2</sub>NiO<sub>3</sub>F<sub>2</sub> and La<sub>2</sub>NiO<sub>2.5</sub>F<sub>3</sub>, which exhibit distinct structural distortions. <i>In situ</i> X-ray diffraction experiments, performed on a laboratory diffractometer, revealed the presence of four distinct reaction intermediates. The crystal structures of these intermediates were further elucidated through X-ray and neutron powder diffraction experiments, complemented by <i>in situ</i> neutron powder diffraction data obtained using a setup featuring a low-background cell made from single-crystalline sapphire. <sup>19</sup>F MAS NMR spectroscopy was employed to localize the fluoride ions and to track the consumption of PVDF. By systematically optimizing reaction conditions, we successfully obtained both oxyfluorides and quantified the phase evolution of all intermediates through extensive Rietveld refinements, yielding the following reaction steps: La<sub>2</sub>NiO<sub>4</sub> (<i>I</i>4/<i>mmm</i>) → Inter#1 (<i>Fmmm</i>) → Inter#2 (<i>Fmmm</i>, with increased orthorhombic distortion) → Inter#3 (<i>C</i>2/<i>c</i>) → La<sub>2</sub>NiO<sub>3</sub>F<sub>2</sub> (<i>Cccm</i>). In the presence of 50% excess PVDF, La<sub>2</sub>NiO<sub>3</sub>F<sub>2</sub> is not obtained from Inter#3 and the reaction instead progresses via Inter#4 (<i>P</i>4<sub>2</sub>/<i>nnm</i>) to La<sub>2</sub>NiO<sub>2.5</sub>F<sub>3</sub> (<i>P</i>4<sub>2</sub>/<i>nnm</i>, with a larger unit cell). This study demonstrates the power of laboratory <i>in situ</i> XRD experiments in elucidating complex fluorination reaction mechanisms, enabling the synthesis of new oxyfluorides with interesting physical properties. The <i>in situ</i> approach represents a significant advancement over traditional trial-and-error methods, which are still prevalent in solid-state synthesis.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"5 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Allen LaCour, Joseph P. Heindel, Ruoqi Zhao, Teresa Head-Gordon
A wide variety of reactions are reported to be dramatically accelerated in aqueous microdroplets, making them a promising platform for environmentally clean chemical synthesis. However, to fully utilize the microdroplets for accelerating chemical reactions requires a fundamental understanding of how microdroplet chemistry differs from that of a homogeneous phase. Here we provide our perspective on recent progress to this end, both experimentally and theoretically. We begin by reviewing the many ways in which microdroplets can be prepared, creating water/hydrophobic interfaces that have been frequently implicated in microdroplet reactivity due to preferential surface adsorption of solutes, persistent electric fields, and their acidity or basicity. These features of the interface interplay with specific mechanisms proposed for microdroplet reactivity, including partial solvation, possible gas phase channels, and the presence of highly reactive intermediates. We especially highlight the role of droplet charge and associated electric fields, which appears to be key to understanding how certain reactions, like the formation of hydrogen peroxide and reduced transition metal complexes, are thermodynamically possible in microdroplets. Lastly, we emphasize opportunities for theoretical advances and suggest experiments that would greatly enhance our understanding of this fascinating subject.
{"title":"The Role of Interfaces and Charge for Chemical Reactivity in Microdroplets","authors":"R. Allen LaCour, Joseph P. Heindel, Ruoqi Zhao, Teresa Head-Gordon","doi":"10.1021/jacs.4c15493","DOIUrl":"https://doi.org/10.1021/jacs.4c15493","url":null,"abstract":"A wide variety of reactions are reported to be dramatically accelerated in aqueous microdroplets, making them a promising platform for environmentally clean chemical synthesis. However, to fully utilize the microdroplets for accelerating chemical reactions requires a fundamental understanding of how microdroplet chemistry differs from that of a homogeneous phase. Here we provide our perspective on recent progress to this end, both experimentally and theoretically. We begin by reviewing the many ways in which microdroplets can be prepared, creating water/hydrophobic interfaces that have been frequently implicated in microdroplet reactivity due to preferential surface adsorption of solutes, persistent electric fields, and their acidity or basicity. These features of the interface interplay with specific mechanisms proposed for microdroplet reactivity, including partial solvation, possible gas phase channels, and the presence of highly reactive intermediates. We especially highlight the role of droplet charge and associated electric fields, which appears to be key to understanding how certain reactions, like the formation of hydrogen peroxide and reduced transition metal complexes, are thermodynamically possible in microdroplets. Lastly, we emphasize opportunities for theoretical advances and suggest experiments that would greatly enhance our understanding of this fascinating subject.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"34 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Subwavelength resonant nanostructures have facilitated strong light–matter interactions and tunable degrees of freedom of light, such as spectrum, polarization, and direction, thus boosting photonic applications toward light emission, manipulation, and detection. For photodetection, resonant nanostructures have enabled emerging technologies, such as light detection and ranging, spectrometers, and polarimeters, within an ultracompact footprint. However, resonant nanophotonics usually relies on nanofabrication technology, which suffers from the trade-offs between precision and scalability. Here, we first realize the self-assembly of subwavelength resonant nanostructures of metal-halide perovskites for spatial object localization and tracking. By steering crystallization along capillary corner bridges localized at edges, we achieve single crystallinity, subwavelength size, and resonant coupling between perovskite nanowires, thus leading to an angle-resolved photodetector with an angular resolution of 0.523°. Furthermore, we integrate multiple pairs of coupled resonant nanowires along two orthogonal orientations to form angle-resolved photodetector arrays for spatial light localization of both static and moving objects with an error of less than 0.6 cm. These findings create a platform for self-assembled resonant nanostructures, thus paving the way for multifunctional nanophotonic and optoelectronic devices.
{"title":"Self-Assembled Subwavelength Nanophotonic Structures for Spatial Object Localization and Tracking","authors":"Jianpeng Ma, Ziguang Zhao, Yingjie Zhao, Jingyuan Zhang, Jiangang Feng, Hanfei Gao, Junchuan Yang, Meng Yuan, Zhenglian Qin, Ke He, Tenglong Li, Junli Bai, Wei Li, Xiao Wei, Zihao Huang, Fengmian Li, Lei Jiang, Yuchen Wu","doi":"10.1021/jacs.4c14899","DOIUrl":"https://doi.org/10.1021/jacs.4c14899","url":null,"abstract":"Subwavelength resonant nanostructures have facilitated strong light–matter interactions and tunable degrees of freedom of light, such as spectrum, polarization, and direction, thus boosting photonic applications toward light emission, manipulation, and detection. For photodetection, resonant nanostructures have enabled emerging technologies, such as light detection and ranging, spectrometers, and polarimeters, within an ultracompact footprint. However, resonant nanophotonics usually relies on nanofabrication technology, which suffers from the trade-offs between precision and scalability. Here, we first realize the self-assembly of subwavelength resonant nanostructures of metal-halide perovskites for spatial object localization and tracking. By steering crystallization along capillary corner bridges localized at edges, we achieve single crystallinity, subwavelength size, and resonant coupling between perovskite nanowires, thus leading to an angle-resolved photodetector with an angular resolution of 0.523°. Furthermore, we integrate multiple pairs of coupled resonant nanowires along two orthogonal orientations to form angle-resolved photodetector arrays for spatial light localization of both static and moving objects with an error of less than 0.6 cm. These findings create a platform for self-assembled resonant nanostructures, thus paving the way for multifunctional nanophotonic and optoelectronic devices.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"28 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lei Yang, Congqi Li, Na An, Jinhua Gao, Yanan Wei, Jiawei Qiao, Junpeng Dai, Na Yu, Yan Sun, Qijie Lin, Xin Zhang, Jianqi Zhang, Zheng Tang, Xiaotao Hao, Guanghao Lu, Zhixiang Wei, Ian Manners, Yongbo Kuang, Hui Huang, Antonio Facchetti, Huibin Qiu
Polymer self-assembly offers an important route to construct well-defined nanostructures. However, it remains challenging to assemble polymers into vertically oriented nanostructures. Here, we use a seed-induced confinement self-assembly strategy to construct vertically aligned semiconducting nanobrushes from polyfluorene-based polymers on conductive substrates. Mechanism studies elucidate that the immobilized seeds on the substrate initiate the vertical growth of nanobrushes, and supercritical drying as well as the rigid charged coronas collectively contribute to retaining the vertical architecture. This process enables nanobrushes with ∼40× higher charge mobilities than their bulk film counterparts. Thus, inverted organic solar cells using the nanobrushes as the electron transporting layer (ETL) exhibit a record power conversion efficiency of 18.51% as a result of increased ETL texturing and the ETL-active layer interface favoring electron extraction. Moreover, our approach also enables the uniform growth of nanobrushes on a nanoporous photoanode (bismuth vanadate) for photoelectrochemical water splitting, improving catalyst distribution and electron transfer. Our work presents a feasible approach to fabricating challenging vertical polymer nanostructures, thereby unlocking the tremendous potential of conjugated polymers in optoelectronic applications.
{"title":"Surface-Emanated Vertical Organic Semiconducting Nanobrushes","authors":"Lei Yang, Congqi Li, Na An, Jinhua Gao, Yanan Wei, Jiawei Qiao, Junpeng Dai, Na Yu, Yan Sun, Qijie Lin, Xin Zhang, Jianqi Zhang, Zheng Tang, Xiaotao Hao, Guanghao Lu, Zhixiang Wei, Ian Manners, Yongbo Kuang, Hui Huang, Antonio Facchetti, Huibin Qiu","doi":"10.1021/jacs.4c16540","DOIUrl":"https://doi.org/10.1021/jacs.4c16540","url":null,"abstract":"Polymer self-assembly offers an important route to construct well-defined nanostructures. However, it remains challenging to assemble polymers into vertically oriented nanostructures. Here, we use a seed-induced confinement self-assembly strategy to construct vertically aligned semiconducting nanobrushes from polyfluorene-based polymers on conductive substrates. Mechanism studies elucidate that the immobilized seeds on the substrate initiate the vertical growth of nanobrushes, and supercritical drying as well as the rigid charged coronas collectively contribute to retaining the vertical architecture. This process enables nanobrushes with ∼40× higher charge mobilities than their bulk film counterparts. Thus, inverted organic solar cells using the nanobrushes as the electron transporting layer (ETL) exhibit a record power conversion efficiency of 18.51% as a result of increased ETL texturing and the ETL-active layer interface favoring electron extraction. Moreover, our approach also enables the uniform growth of nanobrushes on a nanoporous photoanode (bismuth vanadate) for photoelectrochemical water splitting, improving catalyst distribution and electron transfer. Our work presents a feasible approach to fabricating challenging vertical polymer nanostructures, thereby unlocking the tremendous potential of conjugated polymers in optoelectronic applications.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"1 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143435636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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