Yang Shen, Yuhao Hu, Jinyan Du, Junchang Guo, Zhenxu Shi, Jianing Song, Tao Zhong, Haoze Yuan, Zhengrong Lin, Dehui Wang, Xu Deng
In marine environments, splash-induced microdroplets are highly aggressive corrosion media, producing metal corrosion rates several times higher than in fully immersed regions. While macroscopic factors contributing to splash-zone corrosion are well established, the chemical reactivity of seawater microdroplets provides a previously underappreciated complementary mechanism that further enhances corrosion. Here, we demonstrate that the spontaneous generation of reactive radical species within microdroplets significantly accelerates metal oxidation. Notably, the corrosion rate of carbon steel in NaCl microdroplets is over an order of magnitude higher than in NaCl bulk water. Electron paramagnetic resonance and fluorometric assays reveal sustained generation of hydroxyl radicals (·OH) and hydrogen peroxide (H2O2) in microdroplets, negligible in bulk. These species drive a two-stage acceleration: (i) surface ·OH initiates rapid Fe oxidation and (ii) H2O2 reacts with Fe2+ via a cyclic Fenton process, regenerating ·OH and forming an FeOOH layer. Time-of-flight secondary-ion mass spectrometry shows that high-salinity Cl– subsequently displaces FeOOH to form soluble FeOCl, exposing fresh metal and sustaining localized corrosion. This study highlights spontaneously generated reactive species in microdroplets as a key driver of splash zone corrosion, offering insights for radical-targeted protective coatings.
{"title":"Unveiling the Role of Seawater Microdroplets in Accelerating Steel Corrosion","authors":"Yang Shen, Yuhao Hu, Jinyan Du, Junchang Guo, Zhenxu Shi, Jianing Song, Tao Zhong, Haoze Yuan, Zhengrong Lin, Dehui Wang, Xu Deng","doi":"10.1021/jacs.5c20003","DOIUrl":"https://doi.org/10.1021/jacs.5c20003","url":null,"abstract":"In marine environments, splash-induced microdroplets are highly aggressive corrosion media, producing metal corrosion rates several times higher than in fully immersed regions. While macroscopic factors contributing to splash-zone corrosion are well established, the chemical reactivity of seawater microdroplets provides a previously underappreciated complementary mechanism that further enhances corrosion. Here, we demonstrate that the spontaneous generation of reactive radical species within microdroplets significantly accelerates metal oxidation. Notably, the corrosion rate of carbon steel in NaCl microdroplets is over an order of magnitude higher than in NaCl bulk water. Electron paramagnetic resonance and fluorometric assays reveal sustained generation of hydroxyl radicals (·OH) and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) in microdroplets, negligible in bulk. These species drive a two-stage acceleration: (i) surface ·OH initiates rapid Fe oxidation and (ii) H<sub>2</sub>O<sub>2</sub> reacts with Fe<sup>2+</sup> via a cyclic Fenton process, regenerating ·OH and forming an FeOOH layer. Time-of-flight secondary-ion mass spectrometry shows that high-salinity Cl<sup>–</sup> subsequently displaces FeOOH to form soluble FeOCl, exposing fresh metal and sustaining localized corrosion. This study highlights spontaneously generated reactive species in microdroplets as a key driver of splash zone corrosion, offering insights for radical-targeted protective coatings.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"51 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147479051","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}
Zihan Zhang, Weiqing Mao, Haowei Chen, Frank W. Heinemann, Andreas Scheurer, Frank Neese, Karsten Meyer
N-anchored tripodal N-heterocyclic carbene ligands, satTIMMNMes and Me2TIMMNMes, were synthesized and used to stabilize a series of mid-valent Fe(IV) and high-valent Fe(V) and Fe(VI) nitrides. The Fe(IV) and Fe(V) species adopt trigonal-pyramidal and trigonal-bipyramidal geometries, respectively, whereas the Fe(VI) nitrides exhibit octahedral coordination, representing rare examples of structurally characterized iron(VI) nitrido complexes. All complexes were characterized by single-crystal X-ray diffraction, multinuclear (1H, 13C, 15N, and 19F) NMR, zero- and applied-field 57Fe Mössbauer, electron paramagnetic resonance, as well as vibrational and electronic absorption spectroscopy. Combined spectroscopic, electrochemical, and computational studies examined how systematic variation in the NHC backbone modulates the electronic structures of the [Fe≡N]n+ and Fe–CNHC moieties. Structural and spectroscopic parameters of Me2TIMMNMes-based Fe(IV–VI) nitrides closely resemble those of parent TIMMNMes analogues, while more pronounced deviations are observed for satTIMMNMes derivatives. 57Fe Mössbauer spectroscopy at 80 K revealed an unusually negative isomer shift for the tetravalent (d4, S = 0) [(satTIMMNMes)FeIV≡N]+ (δ = −0.45 mm s–1), distinct from Me2TIMMNMes and TIMMNMes analogues (δ = −0.36 and −0.35 mm s–1), attributable to enhanced Fe–CNHC covalency in satTIMMNMes ligand. Cyclic voltammetry, supported by theoretical calculations, quantifies relative ligand π-donation in the Fe(IV) nitrido complexes, complementary to established NHC σ-donor descriptors, yielding the trend satTIMMNMes < TIMMNMes < Me2TIMMNMes. Consistent with this trend, structural and EPR data indicate differing degrees of Jahn–Teller distortion among the paramagnetic Fe(V) nitrides (d3, S = 1/2). In contrast, the structural and spectroscopic differences are relatively diminished in highly covalent Fe(VI) nitrides (d2, S = 0).
合成了n锚定的三足n杂环碳配体satTIMMNMes和Me2TIMMNMes，并用于稳定一系列中价铁（IV）和高价铁(V)和铁（VI）氮化物。铁（IV）和铁(V)分别呈三角-锥体和三角-双锥体结构，而铁（VI）氮化物呈八面体配位，是罕见的结构表征铁（VI）氮化配合物。通过单晶x射线衍射、多核（1H、13C、15N和19F） NMR、零场和应用场57Fe Mössbauer、电子顺磁共振以及振动和电子吸收光谱对所有配合物进行了表征。结合光谱、电化学和计算研究，研究了NHC主链的系统变化如何调节[Fe≡N] N +和Fe - cnhc基团的电子结构。me2timmnmes基Fe（IV-VI）氮化物的结构和光谱参数与母体TIMMNMes类似物非常相似，而satTIMMNMes衍生物的差异更明显。57Fe Mössbauer光谱在80 K下显示了四价（d4, S = 0） [(satTIMMNMes)FeIV≡N]+ (δ = - 0.45 mm S - 1)的异常负同分异构体位移，不同于Me2TIMMNMes和TIMMNMes类似物（δ = - 0.36和- 0.35 mm S - 1），这是由于satTIMMNMes配体中Fe-CNHC共价增强。循环伏安法在理论计算的支持下，量化了Fe(IV) nitrido配合物中相对配体的π给体，与已建立的NHC σ给体描述符互补，得到了satTIMMNMes <； TIMMNMes <； Me2TIMMNMes趋势。与这一趋势一致的是，结构和EPR数据表明顺磁性Fe(V)氮化物（d3, S = 1/2）之间存在不同程度的Jahn-Teller畸变。相比之下，高共价Fe（VI）氮化物的结构和光谱差异相对较小（d2, S = 0）。
{"title":"Revisiting NHC–Metal Bonding: π-Donation in Mid- to High-Valent Iron Nitrido Complexes Stabilizes the Fe(VI) Oxidation State","authors":"Zihan Zhang, Weiqing Mao, Haowei Chen, Frank W. Heinemann, Andreas Scheurer, Frank Neese, Karsten Meyer","doi":"10.1021/jacs.5c21276","DOIUrl":"https://doi.org/10.1021/jacs.5c21276","url":null,"abstract":"N-anchored tripodal N-heterocyclic carbene ligands, <sup>sat</sup>TIMMN<sup>Mes</sup> and <sup>Me2</sup>TIMMN<sup>Mes</sup>, were synthesized and used to stabilize a series of mid-valent Fe(IV) and high-valent Fe(V) and Fe(VI) nitrides. The Fe(IV) and Fe(V) species adopt trigonal-pyramidal and trigonal-bipyramidal geometries, respectively, whereas the Fe(VI) nitrides exhibit octahedral coordination, representing rare examples of structurally characterized iron(VI) nitrido complexes. All complexes were characterized by single-crystal X-ray diffraction, multinuclear (<sup>1</sup>H, <sup>13</sup>C, <sup>15</sup>N, and <sup>19</sup>F) NMR, zero- and applied-field <sup>57</sup>Fe Mössbauer, electron paramagnetic resonance, as well as vibrational and electronic absorption spectroscopy. Combined spectroscopic, electrochemical, and computational studies examined how systematic variation in the NHC backbone modulates the electronic structures of the [Fe≡N]<sup><i>n</i>+</sup> and Fe–C<sub>NHC</sub> moieties. Structural and spectroscopic parameters of <sup>Me2</sup>TIMMN<sup>Mes</sup>-based Fe(IV–VI) nitrides closely resemble those of parent TIMMN<sup>Mes</sup> analogues, while more pronounced deviations are observed for <sup>sat</sup>TIMMN<sup>Mes</sup> derivatives. <sup>57</sup>Fe Mössbauer spectroscopy at 80 K revealed an unusually negative isomer shift for the tetravalent (<i>d</i><sup>4</sup>, <i>S</i> = 0) [(<sup>sat</sup>TIMMN<sup>Mes</sup>)Fe<sup>IV</sup>≡N]<sup>+</sup> (δ = −0.45 mm s<sup>–1</sup>), distinct from <sup>Me2</sup>TIMMN<sup>Mes</sup> and TIMMN<sup>Mes</sup> analogues (δ = −0.36 and −0.35 mm s<sup>–1</sup>), attributable to enhanced Fe–C<sub>NHC</sub> covalency in <sup>sat</sup>TIMMN<sup>Mes</sup> ligand. Cyclic voltammetry, supported by theoretical calculations, quantifies relative ligand π-donation in the Fe(IV) nitrido complexes, complementary to established NHC σ-donor descriptors, yielding the trend <sup>sat</sup>TIMMN<sup>Mes</sup> < TIMMN<sup>Mes</sup> < <sup>Me2</sup>TIMMN<sup>Mes</sup>. Consistent with this trend, structural and EPR data indicate differing degrees of Jahn–Teller distortion among the paramagnetic Fe(V) nitrides (<i>d</i><sup>3</sup>, <i>S</i> = 1/2). In contrast, the structural and spectroscopic differences are relatively diminished in highly covalent Fe(VI) nitrides (<i>d</i><sup>2</sup>, <i>S</i> = 0).","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"27 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147479052","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}
Ayana Miyata, Shun Tokuda, Mako Kuzumoto, Guan-Sian Lee, Masataka Yamashita, Taichi Nishiguchi, Masaki Negoro, Brian R. Pauw, Yi-Tsu Chan, Kazuyoshi Kanamori, Kenji Urayama, Kunihisa Sugimoto, Shuhei Furukawa
Supramolecular systems exhibit collective functions that emerge from the hierarchical assembly of individual molecular building blocks. Metal–organic polyhedra (MOPs) are a class of functional supramolecular architectures with well-defined molecular geometry and an intrinsic cavity. In recent years, considerable progress has been made in assembling MOPs into extended networks to create porous solids. However, most reported MOP assemblies are limited to three-dimensional networks, which, owing to their high-dimensional connectivity, hinder effective stress dissipation and render them brittle under mechanical stress. Here, we report the one-dimensional (1D) self-assembly of MOPs into supramolecular polymeric aerogels that combine permanent microporosity with exceptional mechanical flexibility. The reaction between amino acid-functionalized naphthalenediimide (NDI) linkers and copper salts led to the synthesis of octahedral copper-based MOPs, followed by their spontaneous self-assembly to form supramolecular gels. The corresponding aerogels converted from the gels possessed uniform 1D fibrillar networks (14.8 ± 2.2 nm in width) with intrinsic microporosity derived from individual MOP cavities. The aerogel endured 87% compressive strain without fracture, demonstrating distinct ductility. Furthermore, these fibrils in the supramolecular gels were converted to crystals after 2 weeks. Single-crystal X-ray diffraction revealed that MOPs are arranged via face-to-face interaction between octahedral MOPs to form a 1D helical chain structure. An analysis of the self-assembly process using Hansen solubility parameters unveiled that solvent conditions with high polarity and low dispersion interaction drive the formation of anisotropic assemblies. This work provides a new strategy for tailoring the mechanical properties of supramolecular materials through dimensional control of their assemblies.
{"title":"One-Dimensional van der Waals Porous Fibrils Assembled from Metal–Organic Polyhedra","authors":"Ayana Miyata, Shun Tokuda, Mako Kuzumoto, Guan-Sian Lee, Masataka Yamashita, Taichi Nishiguchi, Masaki Negoro, Brian R. Pauw, Yi-Tsu Chan, Kazuyoshi Kanamori, Kenji Urayama, Kunihisa Sugimoto, Shuhei Furukawa","doi":"10.1021/jacs.5c21654","DOIUrl":"https://doi.org/10.1021/jacs.5c21654","url":null,"abstract":"Supramolecular systems exhibit collective functions that emerge from the hierarchical assembly of individual molecular building blocks. Metal–organic polyhedra (MOPs) are a class of functional supramolecular architectures with well-defined molecular geometry and an intrinsic cavity. In recent years, considerable progress has been made in assembling MOPs into extended networks to create porous solids. However, most reported MOP assemblies are limited to three-dimensional networks, which, owing to their high-dimensional connectivity, hinder effective stress dissipation and render them brittle under mechanical stress. Here, we report the one-dimensional (1D) self-assembly of MOPs into supramolecular polymeric aerogels that combine permanent microporosity with exceptional mechanical flexibility. The reaction between amino acid-functionalized naphthalenediimide (NDI) linkers and copper salts led to the synthesis of octahedral copper-based MOPs, followed by their spontaneous self-assembly to form supramolecular gels. The corresponding aerogels converted from the gels possessed uniform 1D fibrillar networks (14.8 ± 2.2 nm in width) with intrinsic microporosity derived from individual MOP cavities. The aerogel endured 87% compressive strain without fracture, demonstrating distinct ductility. Furthermore, these fibrils in the supramolecular gels were converted to crystals after 2 weeks. Single-crystal X-ray diffraction revealed that MOPs are arranged via face-to-face interaction between octahedral MOPs to form a 1D helical chain structure. An analysis of the self-assembly process using Hansen solubility parameters unveiled that solvent conditions with high polarity and low dispersion interaction drive the formation of anisotropic assemblies. This work provides a new strategy for tailoring the mechanical properties of supramolecular materials through dimensional control of their assemblies.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"1 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147479053","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}
Plant secondary cell walls constitute the dominant reservoir of renewable biomass, comprising tightly packed cellulose, hemicellulose, and lignin at the nanoscale. Recent advances in solid-state NMR spectroscopy and the availability of small-angle X-ray scattering for biomass characterization have led to an accumulation of experimental data on cell wall organization, yet no explicit structure model has simultaneously satisfied both X-ray and NMR observations. Using wheat straw as a model system, we propose a structural framework consistent with current knowledge of cellulose biosynthesis, X-ray scattering data, and one- and two-dimensional 13C solid-state NMR spectra. In this model, 18-chain elementary fibrils align in parallel and populate the cross-section at random. Arabinose-substituted xylan shows no conformational dependence for cellulose-binding in wheat, and only a minor fraction of 2-fold xylan appears in close proximity to cellulose, unlike in Arabidopsis, where xylan is more tightly attached to the cellulose surface. While NMR data cannot unambiguously resolve the internal arrangement of the 18 glucan chains, X-ray scattering profiles uniquely constrain the fibril size and exclude the possibility of tight bundling in the intact walls. The specific interaction between the matrix polymers and the cellulose elementary fibrils must be reconsidered in light of the small interfibril spaces, which bring the matrix components into spatial proximity with cellulose even in the absence of attractive interactions. These findings provide fundamental molecular-level insight into cellulose fibril architecture and matrix–polymer interactions, resolving longstanding discrepancies between spectroscopic and scattering data and advancing our understanding of biopolymer assembly into structurally and functionally versatile lignocellulosic biomaterials.
{"title":"Native Architecture of Wheat Straw Cell Walls: A Unified Model from X-ray Scattering and Solid-State NMR","authors":"Yucheng Hu, Pan Chen, Peng Xiao, Shixu Yu, Lingfeng Zhou, Zhe Ling, Yutong Zhu, Guohua Miao, Yuan He, Haichao Li, Sheng Chen, Tingting You, Feng Xu, Tuo Wang, Yoshiharu Nishiyama","doi":"10.1021/jacs.5c23116","DOIUrl":"https://doi.org/10.1021/jacs.5c23116","url":null,"abstract":"Plant secondary cell walls constitute the dominant reservoir of renewable biomass, comprising tightly packed cellulose, hemicellulose, and lignin at the nanoscale. Recent advances in solid-state NMR spectroscopy and the availability of small-angle X-ray scattering for biomass characterization have led to an accumulation of experimental data on cell wall organization, yet no explicit structure model has simultaneously satisfied both X-ray and NMR observations. Using wheat straw as a model system, we propose a structural framework consistent with current knowledge of cellulose biosynthesis, X-ray scattering data, and one- and two-dimensional <sup>13</sup>C solid-state NMR spectra. In this model, 18-chain elementary fibrils align in parallel and populate the cross-section at random. Arabinose-substituted xylan shows no conformational dependence for cellulose-binding in wheat, and only a minor fraction of 2-fold xylan appears in close proximity to cellulose, unlike in <i>Arabidopsis</i>, where xylan is more tightly attached to the cellulose surface. While NMR data cannot unambiguously resolve the internal arrangement of the 18 glucan chains, X-ray scattering profiles uniquely constrain the fibril size and exclude the possibility of tight bundling in the intact walls. The specific interaction between the matrix polymers and the cellulose elementary fibrils must be reconsidered in light of the small interfibril spaces, which bring the matrix components into spatial proximity with cellulose even in the absence of attractive interactions. These findings provide fundamental molecular-level insight into cellulose fibril architecture and matrix–polymer interactions, resolving longstanding discrepancies between spectroscopic and scattering data and advancing our understanding of biopolymer assembly into structurally and functionally versatile lignocellulosic biomaterials.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"20 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147479056","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}
Katharina Trapp, Soracha Kosasang, Johannes Ingenmey, Dario Gomez Vazquez, Manuel Reiter, Mathieu Salanne, Maria R. Lukatskaya
We disentangle reactant concentration from local structural effects in water-in-salt electrolytes using the formate oxidation reaction on Pt. First, we observe that formate oxidation currents plateau at high concentrations. Using molecular dynamics and NMR spectroscopy, we attribute this observation to ion clustering of the kosmotropic formate reactant, which reduces conductivity and impedes reactant transport. Then, we demonstrate that this limitation can be overcome by introducing a chaotropic anion (perchlorate) that disrupts clustering and facilitates a further increase in formate oxidation currents. However, when perchlorate is introduced in excess, the hydrogen-bonding network is disrupted, which leads to hindered proton transport, local acidification, and enhanced CO poisoning, as evidenced by SEIRAS. Our findings demonstrate a direct link between bulk electrolyte structure and catalytic activity, which can be used to enhance catalytic performance at high reactant concentrations.
{"title":"Electrolyte Structure Governs Formate Oxidation in Water-in-Salt Systems","authors":"Katharina Trapp, Soracha Kosasang, Johannes Ingenmey, Dario Gomez Vazquez, Manuel Reiter, Mathieu Salanne, Maria R. Lukatskaya","doi":"10.1021/jacs.5c19298","DOIUrl":"https://doi.org/10.1021/jacs.5c19298","url":null,"abstract":"We disentangle reactant concentration from local structural effects in water-in-salt electrolytes using the formate oxidation reaction on Pt. First, we observe that formate oxidation currents plateau at high concentrations. Using molecular dynamics and NMR spectroscopy, we attribute this observation to ion clustering of the kosmotropic formate reactant, which reduces conductivity and impedes reactant transport. Then, we demonstrate that this limitation can be overcome by introducing a chaotropic anion (perchlorate) that disrupts clustering and facilitates a further increase in formate oxidation currents. However, when perchlorate is introduced in excess, the hydrogen-bonding network is disrupted, which leads to hindered proton transport, local acidification, and enhanced CO poisoning, as evidenced by SEIRAS. Our findings demonstrate a direct link between bulk electrolyte structure and catalytic activity, which can be used to enhance catalytic performance at high reactant concentrations.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"111 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147479058","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}
Expanding zeolite pore sizes beyond the microporous regime has long been limited by conventional organic structure-directing agents (OSDAs). Here we report JU-69, a mesoporous pure-silica zeolite that features one-dimensional 36-ring channels, representing the largest apertures (19.5 Å × 25.2 Å) observed in any known TO4-based zeolite framework and an ultralow framework density of 9.53 T per 1000 Å3 (T: tetrahedral framework atom). A surfactant-like phosphonium OSDA with bulky head groups and a long alkyl chain directs columnar assemblies that template long-range-ordered mesoporous walls. Three-dimensional electron diffraction reveals a trigonal framework built from three composite building units (CBUs), including cas and two previously unknown CBUs that generate chiral clover arrangements and circular 36-ring pores. The structure is further validated by atomic-resolution real-space imaging using electron ptychography. JU-69 exhibits thermal stability up to 900 °C and periodically arranged silanol groups that enable efficient metal anchoring, demonstrated by active Pd/JU-69 catalysts for bulky molecule hydrogenation. This work establishes a pathway for designing crystalline mesoporous zeolites with unprecedented structural openness.
长期以来，传统的有机结构导向剂（OSDAs）一直限制着沸石孔径的扩展。在这里，我们报道了一种介孔纯硅分子筛ju69，具有一维36环通道，代表了在任何已知的to4基分子筛框架中观察到的最大孔径（19.5 Å × 25.2 Å）和超低的框架密度9.53 T / 1000 Å3 （T：四面体框架原子）。一种表面活性剂样的磷OSDA具有庞大的头基团和长烷基链，指导柱状组装，模板远程有序介孔壁。三维电子衍射揭示了一个由三个复合结构单元（CBUs）组成的三角形框架，包括cas和两个以前未知的CBUs，它们产生手性三叶草排列和36环圆形孔。该结构通过原子分辨率电子平面成像进一步验证。JU-69具有高达900°C的热稳定性，并且周期性排列的硅醇基团能够有效地锚定金属，活性Pd/JU-69催化剂证明了这一点。这项工作为设计具有前所未有的结构开放性的晶体介孔沸石开辟了一条途径。
{"title":"A Stable Mesoporous Zeolite with Superlarge 36-Ring Channels.","authors":"Aimin Gong,Chenyang Nie,Haodi Ding,Cailing Chen,Qiang Zhang,Guangyuan He,Xilin Jia,Nairui Liu,Tianpeng Li,Yecheng Li,Zijiang Jiang,Donghai Mei,Yu Han,Peng Guo,Fei-Jian Chen,Jihong Yu","doi":"10.1021/jacs.6c01322","DOIUrl":"https://doi.org/10.1021/jacs.6c01322","url":null,"abstract":"Expanding zeolite pore sizes beyond the microporous regime has long been limited by conventional organic structure-directing agents (OSDAs). Here we report JU-69, a mesoporous pure-silica zeolite that features one-dimensional 36-ring channels, representing the largest apertures (19.5 Å × 25.2 Å) observed in any known TO4-based zeolite framework and an ultralow framework density of 9.53 T per 1000 Å3 (T: tetrahedral framework atom). A surfactant-like phosphonium OSDA with bulky head groups and a long alkyl chain directs columnar assemblies that template long-range-ordered mesoporous walls. Three-dimensional electron diffraction reveals a trigonal framework built from three composite building units (CBUs), including cas and two previously unknown CBUs that generate chiral clover arrangements and circular 36-ring pores. The structure is further validated by atomic-resolution real-space imaging using electron ptychography. JU-69 exhibits thermal stability up to 900 °C and periodically arranged silanol groups that enable efficient metal anchoring, demonstrated by active Pd/JU-69 catalysts for bulky molecule hydrogenation. This work establishes a pathway for designing crystalline mesoporous zeolites with unprecedented structural openness.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"88 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147471731","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}
Macrocyclic compounds are widespread in nature and frequently found among bioactive natural products. Their conformational preorganization allows them to effectively engage large binding surfaces, making them valuable in drug discovery, especially for modulating protein-protein interactions. Consequently, macrocyclization strategies have received significant attention; however, they still typically rely on high-dilution conditions (0.10-10 mM) to favor intramolecular ring closure over intermolecular oligomerization. Here, we report a solution to this long-standing challenge using a catalytic confined-space approach that operates efficiently even at the substrate solubility limit (600 mM), thereby eliminating the need for high-dilution conditions. The capsular catalyst enables the high-yielding formation of medium- and large-sized glycosidic macrocycles with excellent β-selectivity. Moreover, the method addresses a second persistent challenge in macrocyclization: the selective formation of macrocyclic dimers. Whereas such dimers are inaccessible under traditional high-dilution conditions, they are obtained in high yields when two substrates fit into the capsule's cavity, again at high substrate concentrations and with excellent β,β-selectivity. Control experiments establish the indispensability of the capsule as conventional conditions afford substantially lower yields and predominantly α-selectivity. The method's utility is further demonstrated in the selective synthesis of the dimeric core structure of glucolipsin A and cycloviracin B1. This work establishes confinement catalysis as a powerful tool to overcome key limitations in macrocyclization chemistry.
{"title":"Confinement Catalysis Enables Macrocyclization at Up to 0.6 M: Selective Formation of Mono- and Dimeric Glycosidic Macrocycles.","authors":"Sudip Guria,Julia Bechter,Alessandro Prescimone,Konrad Tiefenbacher","doi":"10.1021/jacs.6c03730","DOIUrl":"https://doi.org/10.1021/jacs.6c03730","url":null,"abstract":"Macrocyclic compounds are widespread in nature and frequently found among bioactive natural products. Their conformational preorganization allows them to effectively engage large binding surfaces, making them valuable in drug discovery, especially for modulating protein-protein interactions. Consequently, macrocyclization strategies have received significant attention; however, they still typically rely on high-dilution conditions (0.10-10 mM) to favor intramolecular ring closure over intermolecular oligomerization. Here, we report a solution to this long-standing challenge using a catalytic confined-space approach that operates efficiently even at the substrate solubility limit (600 mM), thereby eliminating the need for high-dilution conditions. The capsular catalyst enables the high-yielding formation of medium- and large-sized glycosidic macrocycles with excellent β-selectivity. Moreover, the method addresses a second persistent challenge in macrocyclization: the selective formation of macrocyclic dimers. Whereas such dimers are inaccessible under traditional high-dilution conditions, they are obtained in high yields when two substrates fit into the capsule's cavity, again at high substrate concentrations and with excellent β,β-selectivity. Control experiments establish the indispensability of the capsule as conventional conditions afford substantially lower yields and predominantly α-selectivity. The method's utility is further demonstrated in the selective synthesis of the dimeric core structure of glucolipsin A and cycloviracin B1. This work establishes confinement catalysis as a powerful tool to overcome key limitations in macrocyclization chemistry.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"11 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147471799","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}
Wei Du, Wen Liu, Shuangshuang Cha, Tao Jiang, Mengxin Qu, Zhongqiang Deng, Can Lei, Zhong-Kang Han, Xinhe Bao, Ming Gong
1,4-Butanediol (1,4-BDO) is an important chemical with growing interest due to its use in biodegradable polymers. Its conventional synthesis by the Reppe process involves the condensation of acetylene and formaldehyde, followed by hydrogenation, demanding multiple steps and stringent safety/environmental regulation. In this work, we demonstrated the electrosynthesis of 1,4-BDO from ethylene and water by coupling the reductive coupling of 2-bromoethanol (2-Br-EtOH) with the Br– redox. The homocoupling of 2-Br-EtOH into 1,4-BDO was the limiting reaction. By a data-mining-assisted approach, we identified N-based ligands with an -NH2 group and appropriate Fukui functions as promoters for 1,4-BDO formation on Cu electrodes. The optimal 2-aminoimidazole ligand could generate 55.1% yield and 61.4% selectivity of 1,4-BDO from 2-Br-EtOH, by facilitating surface Cu+ formation for homocoupling, suppressing adsorbed hydrogen formation for hydrogenation, and retarding electron injection to create a local pH gradient toward the non-Faradaic production of ethylene oxide. By integrating the anode with hydrophobic carbon for Br– oxidation and its sequential reaction with gaseous ethylene into 2-Br-EtOH, we demonstrated the 1,4-BDO electrosynthesis under internal 2-Br-EtOH and Br– cycling, with ethanol as the only side product. This work extends the industrial synthetic strategy toward 1,4-BDO to a safe and green electrocatalytic route using low-cost ethylene and water as raw materials.
{"title":"Surface Coordination-Promoted Electrosynthesis of 1,4-Butanediol from Ethylene and Water via 2-Bromoethanol","authors":"Wei Du, Wen Liu, Shuangshuang Cha, Tao Jiang, Mengxin Qu, Zhongqiang Deng, Can Lei, Zhong-Kang Han, Xinhe Bao, Ming Gong","doi":"10.1021/jacs.5c22003","DOIUrl":"https://doi.org/10.1021/jacs.5c22003","url":null,"abstract":"1,4-Butanediol (1,4-BDO) is an important chemical with growing interest due to its use in biodegradable polymers. Its conventional synthesis by the Reppe process involves the condensation of acetylene and formaldehyde, followed by hydrogenation, demanding multiple steps and stringent safety/environmental regulation. In this work, we demonstrated the electrosynthesis of 1,4-BDO from ethylene and water by coupling the reductive coupling of 2-bromoethanol (2-Br-EtOH) with the Br<sup>–</sup> redox. The homocoupling of 2-Br-EtOH into 1,4-BDO was the limiting reaction. By a data-mining-assisted approach, we identified N-based ligands with an -NH<sub>2</sub> group and appropriate Fukui functions as promoters for 1,4-BDO formation on Cu electrodes. The optimal 2-aminoimidazole ligand could generate 55.1% yield and 61.4% selectivity of 1,4-BDO from 2-Br-EtOH, by facilitating surface Cu<sup>+</sup> formation for homocoupling, suppressing adsorbed hydrogen formation for hydrogenation, and retarding electron injection to create a local pH gradient toward the non-Faradaic production of ethylene oxide. By integrating the anode with hydrophobic carbon for Br<sup>–</sup> oxidation and its sequential reaction with gaseous ethylene into 2-Br-EtOH, we demonstrated the 1,4-BDO electrosynthesis under internal 2-Br-EtOH and Br<sup>–</sup> cycling, with ethanol as the only side product. This work extends the industrial synthetic strategy toward 1,4-BDO to a safe and green electrocatalytic route using low-cost ethylene and water as raw materials.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"1 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147479065","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}
Jixi Wang, Zhoumei Tan, Hai-Chao Xu, Kun Xu, Chengchu Zeng
The catalytic upgrading of bulk feedstock chemicals into value-added products represents a powerful approach in modern chemical synthesis. Herein, we describe an iron-catalyzed photoelectrochemical strategy that enables the efficient conversion of nitromethane (MeNO2), an abundant industrial feedstock, into synthetically valuable nitric oxide (·NO). This proof-of-concept platform allows the direct synthesis of structurally diverse oximes from MeNO2 and alcohols and exhibits broad functional group tolerance, including compatibility with carbonyl groups and acid-sensitive motifs such as esters and silyl ethers. Mechanistic investigations reveal that the iron catalyst plays a dual role: promoting radical deformylation of alcohols or ring-opening of cycloalkanols and mediating the conversion of MeNO2 into ·NO.
{"title":"Photoelectrochemical Valorization of Nitromethane for Oxime Synthesis.","authors":"Jixi Wang, Zhoumei Tan, Hai-Chao Xu, Kun Xu, Chengchu Zeng","doi":"10.1021/jacs.6c02923","DOIUrl":"10.1021/jacs.6c02923","url":null,"abstract":"<p><p>The catalytic upgrading of bulk feedstock chemicals into value-added products represents a powerful approach in modern chemical synthesis. Herein, we describe an iron-catalyzed photoelectrochemical strategy that enables the efficient conversion of nitromethane (MeNO<sub>2</sub>), an abundant industrial feedstock, into synthetically valuable nitric oxide (·NO). This proof-of-concept platform allows the direct synthesis of structurally diverse oximes from MeNO<sub>2</sub> and alcohols and exhibits broad functional group tolerance, including compatibility with carbonyl groups and acid-sensitive motifs such as esters and silyl ethers. Mechanistic investigations reveal that the iron catalyst plays a dual role: promoting radical deformylation of alcohols or ring-opening of cycloalkanols and mediating the conversion of MeNO<sub>2</sub> into ·NO.</p>","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":" ","pages":""},"PeriodicalIF":15.6,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147479142","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}
Lanthanum-based compounds are cornerstones of superconductivity research, yet the La 5d orbitals typically remain empty spectator states far above the Fermi level (EF). While superconductivity has been induced in LaO up to 5.37 K in tensile epitaxy films, the intrinsic ground state of the bulk phase has remained controversial mostly due to synthetic challenges, with early reports suggesting a metallic nature. Here we report the high-pressure and high-temperature synthesis of pure bulk rock-salt LaO and unveil its intrinsic type-II superconductivity with a transition temperature (TC) of ∼6 K at ambient pressure. The bulk TC is further enhanced to 6.9 K in La1-xYxO at x = 0.10, where Y doping leads to lattice contraction (chemical pressing) and a remarkable increase in electron carrier concentration. Strikingly, applying physical pressure further enhances the TC to a maximum of 12.7 K at 20 GPa, the highest TC in lanthanum monochalcogenides LaX (X = S, Se, Te, and O) to date. This pressure dependence is diametrically opposed to the behavior observed in films, and occurs despite a pressure-induced reduction in the density of states at EF─a trend that sharply contradicts the conventional phonon-mediated BCS mechanism. Our first-principles calculations reveal that compressive strain modifies the crystal field splitting to enhance La 5d/O 2p hybridization, fostering a three-dimensional multipocket Fermi surface favorable for spin/orbital fluctuation-mediated pairing. This work clarifies the intrinsic superconductivity of bulk LaO and provides a foundation for designing new rare-earth-based superconductors with higher TC.
{"title":"3D Unconventional Superconductivity in Bulk LaO.","authors":"Zhifan Wang, Jingkai Bi, Jiayuan Zhang, Wenmin Li, Yuxuan Liu, Dao-Xin Yao, Zheng Deng, Changqing Jin, Yifeng Han, Man-Rong Li","doi":"10.1021/jacs.6c00519","DOIUrl":"10.1021/jacs.6c00519","url":null,"abstract":"<p><p>Lanthanum-based compounds are cornerstones of superconductivity research, yet the La 5d orbitals typically remain empty spectator states far above the Fermi level (<i>E</i><sub>F</sub>). While superconductivity has been induced in LaO up to 5.37 K in tensile epitaxy films, the intrinsic ground state of the bulk phase has remained controversial mostly due to synthetic challenges, with early reports suggesting a metallic nature. Here we report the high-pressure and high-temperature synthesis of pure bulk rock-salt LaO and unveil its intrinsic type-II superconductivity with a transition temperature (<i>T</i><sub>C</sub>) of ∼6 K at ambient pressure. The bulk <i>T</i><sub>C</sub> is further enhanced to 6.9 K in La<sub>1-<i>x</i></sub>Y<sub><i>x</i></sub>O at <i>x</i> = 0.10, where Y doping leads to lattice contraction (chemical pressing) and a remarkable increase in electron carrier concentration. Strikingly, applying physical pressure further enhances the <i>T</i><sub>C</sub> to a maximum of 12.7 K at 20 GPa, the highest <i>T</i><sub>C</sub> in lanthanum monochalcogenides La<i>X</i> (<i>X</i> = S, Se, Te, and O) to date. This pressure dependence is diametrically opposed to the behavior observed in films, and occurs despite a pressure-induced reduction in the density of states at <i>E</i><sub>F</sub>─a trend that sharply contradicts the conventional phonon-mediated BCS mechanism. Our first-principles calculations reveal that compressive strain modifies the crystal field splitting to enhance La 5d/O 2p hybridization, fostering a three-dimensional multipocket Fermi surface favorable for spin/orbital fluctuation-mediated pairing. This work clarifies the intrinsic superconductivity of bulk LaO and provides a foundation for designing new rare-earth-based superconductors with higher <i>T</i><sub>C</sub>.</p>","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":" ","pages":""},"PeriodicalIF":15.6,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147479100","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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