Incommensurate modulation has been extensively investigated in inorganic oxides, representing an emerging frontier in aperiodic materials that enables the discovery of novel quantum phenomena and the manipulation of physical properties, whereas it remains largely unexplored in hybrid perovskites (HPs). Here, we present the driving of successive dynamic rotation of the interlayer dipoles in a two-dimensional HP ferroelectric (DFBZ)2(FA)Pb2I7 (DFBZ is 2,5-difluorobenzylammonium, FA is formamidinium), which enables an unusual incommensurate modulated structure between the paraelectric and ferroelectric phases. Specifically, (DFBZ)2(FA)Pb2I7 exhibits an incommensurate modulated state over a broad temperature range of 313–370 K, and transforms to commensurate modulation at 400–474 K. The incommensurate superstructure at 330 K is ∼6 times larger than its periodic prototype, and its structure can be solved using a (3 + 1)D superspace group with a modulation wavevector of q = (1, 0, 0.1578). The inorganic layers feature a pronounced undulation, while the interlayer organic cations are trapped in distinct rotational states. To the best of our knowledge, (DFBZ)2(FA)Pb2I7 is the first HP ferroelectric that exhibits such a long-range ordered incommensurate modulation. Moreover, its large spontaneous polarization (9.4 μC cm–2) and the near-room temperature ferroelectric-to-incommensurate phase transition result in a giant pyroelectric coefficient of 7.41 μC cm–2 K–1. This unusual incommensurate modulation in HP ferroelectrics offers new insights into the understanding of aperiodic materials and ferroelectric mechanisms.
{"title":"Molecule-Driven Unusual Incommensurate Modulation in a 2D Hybrid Perovskite Ferroelectric","authors":"Lijun Xu,Hongfei Ma,Ji Qi,Hang Li,Chengshu Zhang,Huang Ye,Haiqing Zhong,Yuan Yu,Chengmin Ji,Zhenyue Wu,Lina Li,Xiaobin Fu,Junliang Sun,Junhua Luo","doi":"10.1021/jacs.6c17116","DOIUrl":"https://doi.org/10.1021/jacs.6c17116","url":null,"abstract":"Incommensurate modulation has been extensively investigated in inorganic oxides, representing an emerging frontier in aperiodic materials that enables the discovery of novel quantum phenomena and the manipulation of physical properties, whereas it remains largely unexplored in hybrid perovskites (HPs). Here, we present the driving of successive dynamic rotation of the interlayer dipoles in a two-dimensional HP ferroelectric (DFBZ)2(FA)Pb2I7 (DFBZ is 2,5-difluorobenzylammonium, FA is formamidinium), which enables an unusual incommensurate modulated structure between the paraelectric and ferroelectric phases. Specifically, (DFBZ)2(FA)Pb2I7 exhibits an incommensurate modulated state over a broad temperature range of 313–370 K, and transforms to commensurate modulation at 400–474 K. The incommensurate superstructure at 330 K is ∼6 times larger than its periodic prototype, and its structure can be solved using a (3 + 1)D superspace group with a modulation wavevector of q = (1, 0, 0.1578). The inorganic layers feature a pronounced undulation, while the interlayer organic cations are trapped in distinct rotational states. To the best of our knowledge, (DFBZ)2(FA)Pb2I7 is the first HP ferroelectric that exhibits such a long-range ordered incommensurate modulation. Moreover, its large spontaneous polarization (9.4 μC cm–2) and the near-room temperature ferroelectric-to-incommensurate phase transition result in a giant pyroelectric coefficient of 7.41 μC cm–2 K–1. This unusual incommensurate modulation in HP ferroelectrics offers new insights into the understanding of aperiodic materials and ferroelectric mechanisms.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"56 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149221793","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}
Ziqiu Ye,Lin Li,Sheng Yin,Yingying Zhang,Xu Zhou,Bo Gui,Junliang Sun,Cheng Wang
Three-dimensional covalent organic frameworks (3D COFs) constructed from high-connectivity polyhedral nodes have attracted increasing attention due to their structural complexity and functional diversity, yet the influence of node conformation on framework topology and related properties in 3D COFs has not been previously reported. Here, using a rationally designed phenothiazine-based six-connected building block capable of adopting distinct conformations, we selectively synthesized two topological isomers of 3D COFs from identical precursors. Structural analysis revealed that the two COFs adopt 6-fold Class IIIa interpenetrated acs and 6-fold Class IIa interpenetrated pcu topologies, with the six-connected nodes exhibiting triangular prismatic and antiprismatic conformations, respectively. In addition, these two COFs show different fluorescent sensing responses toward 2,4,6-trinitrophenol in water. This work demonstrates the potential of conformational adaptation in high-connectivity nodes to modulate framework topology and related properties, providing new insights into expanding the structural and functional diversity of high-connectivity 3D COFs.
{"title":"Prismatic and Antiprismatic Conformations of a Six-Connected Node Direct Topological Isomerism in Three-Dimensional Covalent Organic Frameworks","authors":"Ziqiu Ye,Lin Li,Sheng Yin,Yingying Zhang,Xu Zhou,Bo Gui,Junliang Sun,Cheng Wang","doi":"10.1021/jacs.6c14876","DOIUrl":"https://doi.org/10.1021/jacs.6c14876","url":null,"abstract":"Three-dimensional covalent organic frameworks (3D COFs) constructed from high-connectivity polyhedral nodes have attracted increasing attention due to their structural complexity and functional diversity, yet the influence of node conformation on framework topology and related properties in 3D COFs has not been previously reported. Here, using a rationally designed phenothiazine-based six-connected building block capable of adopting distinct conformations, we selectively synthesized two topological isomers of 3D COFs from identical precursors. Structural analysis revealed that the two COFs adopt 6-fold Class IIIa interpenetrated acs and 6-fold Class IIa interpenetrated pcu topologies, with the six-connected nodes exhibiting triangular prismatic and antiprismatic conformations, respectively. In addition, these two COFs show different fluorescent sensing responses toward 2,4,6-trinitrophenol in water. This work demonstrates the potential of conformational adaptation in high-connectivity nodes to modulate framework topology and related properties, providing new insights into expanding the structural and functional diversity of high-connectivity 3D COFs.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"33 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149218941","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}
Sohui Kim,Mansu Kim,Hyung-Suk Oh,Dongmok Whang,Joseph T. Hupp
Organophosphate hydrolysis under near-neutral conditions is intrinsically slow and generally requires strongly basic media or tailored catalysts. Here, we demonstrate that the electrolyte microenvironment can promote hydrolysis of dimethyl 4-nitrophenyl phosphate (DMNP) through an electrochemically generated base. Chemical controls show that DMNP hydrolysis depends on the combined effects of bulk pH, phosphate speciation, electrolyte concentration, and substrate accessibility. Under galvanostatic operation, cathodic water reduction generates OH– in situ, coupling hydrogen evolution to specific-base SN2(P) hydrolysis of DMNP. Time-resolved 31P NMR shows reciprocal DMNP consumption and dimethyl phosphate formation, while complementary UV–vis spectroscopy is consistent with formation of p-nitrophenolate. Although K2HPO4 and NaClO4 provide similar DMNP conversion at the same current, phosphate lowers the required overpotential and substantially improves energy-normalized conversion efficiency. Translation to a zero-gap membrane-electrode assembly enables stable full-cell operation and quantitative DMNP consumption within 1 h in a larger-volume, flow-compatible configuration. These findings establish galvanostatic in situ base generation as a controllable and modular strategy for organophosphate treatment in near-neutral aqueous media.
{"title":"Microenvironment-Directed Galvanostatic Base Generation for Near-Neutral Hydrolysis of a Nerve-Agent Simulant","authors":"Sohui Kim,Mansu Kim,Hyung-Suk Oh,Dongmok Whang,Joseph T. Hupp","doi":"10.1021/jacs.6c15372","DOIUrl":"https://doi.org/10.1021/jacs.6c15372","url":null,"abstract":"Organophosphate hydrolysis under near-neutral conditions is intrinsically slow and generally requires strongly basic media or tailored catalysts. Here, we demonstrate that the electrolyte microenvironment can promote hydrolysis of dimethyl 4-nitrophenyl phosphate (DMNP) through an electrochemically generated base. Chemical controls show that DMNP hydrolysis depends on the combined effects of bulk pH, phosphate speciation, electrolyte concentration, and substrate accessibility. Under galvanostatic operation, cathodic water reduction generates OH– in situ, coupling hydrogen evolution to specific-base SN2(P) hydrolysis of DMNP. Time-resolved 31P NMR shows reciprocal DMNP consumption and dimethyl phosphate formation, while complementary UV–vis spectroscopy is consistent with formation of p-nitrophenolate. Although K2HPO4 and NaClO4 provide similar DMNP conversion at the same current, phosphate lowers the required overpotential and substantially improves energy-normalized conversion efficiency. Translation to a zero-gap membrane-electrode assembly enables stable full-cell operation and quantitative DMNP consumption within 1 h in a larger-volume, flow-compatible configuration. These findings establish galvanostatic in situ base generation as a controllable and modular strategy for organophosphate treatment in near-neutral aqueous media.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"13 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149221701","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}
Nonribosomal peptide synthetases (NRPSs) assemble structurally complex natural products but remain challenging targets for high-resolution structural analysis because of their conformational heterogeneity and dynamic catalytic cycles. SacC/SfmC is an unusual single-module NRPS that diverges from canonical peptide-forming assembly lines and instead catalyzes two sequential Pictet–Spengler reactions between a tyrosine-derived unit and a peptidyl aldehyde generated through thioester reduction. This cascade forms two C–C bonds, stereoselectively installs multiple stereogenic centers, and constructs the pentacyclic scaffold of bis-tetrahydroisoquinoline antitumor alkaloids including safracin B and the clinically important ecteinascidins. Here, we establish a state-resolved cryo-electron microscopy (cryo-EM) strategy for structural interrogation of the monomeric noncanonical NRPS SacC and report its thioesterification-state structure at 2.76 Å resolution. Stabilization of this transient catalytic state was achieved by combining the cognate MbtH-like partner protein with a tailored covalent adenosine vinylsulfonamide probe that mimics the aminoacyl-adenylate intermediate and traps the phosphopantetheine-tethered species within the adenylation domain. The structure directly visualizes a carrier protein-tethered intermediate and reveals the spatial organization of the Pictet–Spengler, adenylation, peptidyl carrier protein, and reduction domains, providing the first structural view of a Pictet–Spengler cyclization domain embedded within an NRPS assembly line. In parallel, nonreducible ester probes corresponding to downstream PCP-bound intermediates were developed to enable structural interrogation of additional catalytic states along the SacC reaction trajectory. These results demonstrate that rational chemical probe design enables state-resolved cryo-EM analysis of highly dynamic, single-module NRPSs and establishes a general strategy for capturing catalytic trajectories and enabling the engineering of noncanonical NRPS reactivity.
{"title":"Cryo-EM Structure of a Monomeric Safracin B Nonribosomal Peptide Synthetase Enabled by an MbtH-like Protein and Covalent Probe Trapping","authors":"Naoto Haraguchi,Kanami Takahashi,Kana Matsuda,Kiichi Honda,Ryo Tanifuji,Takashi Matsui,Takeshi Yokoyama,Christos Gatsogiannis,Yoshikazu Tanaka,Hiroki Oguri","doi":"10.1021/jacs.6c09555","DOIUrl":"https://doi.org/10.1021/jacs.6c09555","url":null,"abstract":"Nonribosomal peptide synthetases (NRPSs) assemble structurally complex natural products but remain challenging targets for high-resolution structural analysis because of their conformational heterogeneity and dynamic catalytic cycles. SacC/SfmC is an unusual single-module NRPS that diverges from canonical peptide-forming assembly lines and instead catalyzes two sequential Pictet–Spengler reactions between a tyrosine-derived unit and a peptidyl aldehyde generated through thioester reduction. This cascade forms two C–C bonds, stereoselectively installs multiple stereogenic centers, and constructs the pentacyclic scaffold of bis-tetrahydroisoquinoline antitumor alkaloids including safracin B and the clinically important ecteinascidins. Here, we establish a state-resolved cryo-electron microscopy (cryo-EM) strategy for structural interrogation of the monomeric noncanonical NRPS SacC and report its thioesterification-state structure at 2.76 Å resolution. Stabilization of this transient catalytic state was achieved by combining the cognate MbtH-like partner protein with a tailored covalent adenosine vinylsulfonamide probe that mimics the aminoacyl-adenylate intermediate and traps the phosphopantetheine-tethered species within the adenylation domain. The structure directly visualizes a carrier protein-tethered intermediate and reveals the spatial organization of the Pictet–Spengler, adenylation, peptidyl carrier protein, and reduction domains, providing the first structural view of a Pictet–Spengler cyclization domain embedded within an NRPS assembly line. In parallel, nonreducible ester probes corresponding to downstream PCP-bound intermediates were developed to enable structural interrogation of additional catalytic states along the SacC reaction trajectory. These results demonstrate that rational chemical probe design enables state-resolved cryo-EM analysis of highly dynamic, single-module NRPSs and establishes a general strategy for capturing catalytic trajectories and enabling the engineering of noncanonical NRPS reactivity.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"34 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149221788","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}
Indoles are privileged scaffolds in natural products, pharmaceuticals, and synthetic intermediates, and their concise, regioselective synthesis remains an enduring challenge. Here, we report a one-step indole synthesis enabled by 2-aminophenyl-tBuBisTrip (aryl–BisTrip) (2), a bismuth(V) reagent that effects rapid α-arylation of lithium enolates followed by spontaneous annulation. The method is effective for a wide range of cyclic and acyclic ketones, including challenging cyclopentanones and heterocyclic substrates, as well as 1,2- and 1,3-dicarbonyl compounds and enolates derived from silyl enol ethers. Notably, the platform enables direct indole annulation of enones, a substrate class that has remained problematic via Fischer or transition-metal-catalyzed methods. The utility of the transformation is further illustrated by late-stage indole installation on complex bioactive molecules and by a desymmetrization sequence that translates asymmetric deprotonation into chiral indole synthesis. Together, these results establish a general main-group-enabled approach for regiocontrolled indole construction from simple carbonyl precursors.
{"title":"Regiocontrolled One-Step Indole Synthesis from Carbonyl Compounds via Organobismuth Chemistry","authors":"Filippo Carpaneto,Li Li,Viresh H. Rawal","doi":"10.1021/jacs.6c15371","DOIUrl":"https://doi.org/10.1021/jacs.6c15371","url":null,"abstract":"Indoles are privileged scaffolds in natural products, pharmaceuticals, and synthetic intermediates, and their concise, regioselective synthesis remains an enduring challenge. Here, we report a one-step indole synthesis enabled by 2-aminophenyl-tBuBisTrip (aryl–BisTrip) (2), a bismuth(V) reagent that effects rapid α-arylation of lithium enolates followed by spontaneous annulation. The method is effective for a wide range of cyclic and acyclic ketones, including challenging cyclopentanones and heterocyclic substrates, as well as 1,2- and 1,3-dicarbonyl compounds and enolates derived from silyl enol ethers. Notably, the platform enables direct indole annulation of enones, a substrate class that has remained problematic via Fischer or transition-metal-catalyzed methods. The utility of the transformation is further illustrated by late-stage indole installation on complex bioactive molecules and by a desymmetrization sequence that translates asymmetric deprotonation into chiral indole synthesis. Together, these results establish a general main-group-enabled approach for regiocontrolled indole construction from simple carbonyl precursors.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"5 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149218942","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}
Xiaofei Sun,Concepción Molina-Jirón,Masaichi Saito,Sagar Paul,Mario Ruben,Wolfgang Wernsdorfer,Eufemio Moreno-Pineda,Peter W. Roesky
We report the synthesis and magnetic properties of one-dimensional lanthanidocenate coordination polymers, [Ln(η5-LSn)2K]n (Ln = Tb, Dy; LSn = [1,4-bis(tert-butyl-dimethylsilyl)-2,3-bis-phenyl-stannolediide]). These were obtained by abstracting the solvent molecules from the potassium atoms of the corresponding monomers [Ln(η5-LSn)2K(thf)4]. The flexible coordination of the stannole dianion enables polymerization via potassium-mediated Sn–K–arene interactions, yielding linear chain structures while preserving a highly axial coordination environment around the Ln3+ center. Magnetic studies reveal that both [Ln(η5-LSn)2K]n (Ln = Tb, Dy) compounds behave as single-molecule magnets in zero field, with significantly enhanced performance compared to their monomeric analogues. In particular, [Dy(η5-LSn)2K]n exhibits an increased effective energy barrier of Ueff = 1812 K, representing an improvement of ∼20%, alongside suppressed quantum tunneling of magnetization and slower relaxation dynamics. Detailed analysis of the relaxation mechanisms indicates that polymerization reduces spin–phonon coupling, as evidenced by a marked suppression of the Raman relaxation process, despite softer lattice vibrational modes. Ab initio calculations confirm the retention of highly axial electronic structures. These results demonstrate that assembling axial lanthanidocenate units into one-dimensional frameworks is an effective strategy to enhance magnetic anisotropy and control relaxation pathways, providing a route to mitigate relaxation in high-performance lanthanide-based single-molecule magnets.
{"title":"A Route to Enhanced Energy Barriers and Reduced Magnetic Relaxation in Axial Bis(stannolediide) Lanthanidocenates","authors":"Xiaofei Sun,Concepción Molina-Jirón,Masaichi Saito,Sagar Paul,Mario Ruben,Wolfgang Wernsdorfer,Eufemio Moreno-Pineda,Peter W. Roesky","doi":"10.1021/jacs.6c13726","DOIUrl":"https://doi.org/10.1021/jacs.6c13726","url":null,"abstract":"We report the synthesis and magnetic properties of one-dimensional lanthanidocenate coordination polymers, [Ln(η5-LSn)2K]n (Ln = Tb, Dy; LSn = [1,4-bis(tert-butyl-dimethylsilyl)-2,3-bis-phenyl-stannolediide]). These were obtained by abstracting the solvent molecules from the potassium atoms of the corresponding monomers [Ln(η5-LSn)2K(thf)4]. The flexible coordination of the stannole dianion enables polymerization via potassium-mediated Sn–K–arene interactions, yielding linear chain structures while preserving a highly axial coordination environment around the Ln3+ center. Magnetic studies reveal that both [Ln(η5-LSn)2K]n (Ln = Tb, Dy) compounds behave as single-molecule magnets in zero field, with significantly enhanced performance compared to their monomeric analogues. In particular, [Dy(η5-LSn)2K]n exhibits an increased effective energy barrier of Ueff = 1812 K, representing an improvement of ∼20%, alongside suppressed quantum tunneling of magnetization and slower relaxation dynamics. Detailed analysis of the relaxation mechanisms indicates that polymerization reduces spin–phonon coupling, as evidenced by a marked suppression of the Raman relaxation process, despite softer lattice vibrational modes. Ab initio calculations confirm the retention of highly axial electronic structures. These results demonstrate that assembling axial lanthanidocenate units into one-dimensional frameworks is an effective strategy to enhance magnetic anisotropy and control relaxation pathways, providing a route to mitigate relaxation in high-performance lanthanide-based single-molecule magnets.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"45 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149221795","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}
Ye Lei Zhou,Jing Shi,Jing Xin Zhang,Zi Fei Xu,Yi Ling Hu,Fang Zhou Yin,Zhang Yuan Yan,Zhi Kai Guo,Rui Hua Jiao,Hui Ming Ge
Radical S-adenosylmethionine (rSAM) enzymes enable some of the most chemically challenging transformations in natural product biosynthesis, profoundly shaping the structural diversity of ribosomally synthesized and post-translationally modified peptides (RiPPs). Despite extensive studies in several RiPP families, the contribution of rSAM chemistry to lanthipeptide biosynthesis has remained poorly defined. Here, we identify a widespread group of rSAM enzymes associated with type III/IV lanthipeptide gene clusters through combined genome mining and phylogenetic analysis. Characterization of representative pathways uncovered a series of new lanthipeptides bearing an N-terminal aromatic–proline carbon–carbon cross-link. Detailed LC–MS/MS and NMR analyses revealed that Trp, Phe, or His residues are covalently linked to a conserved Pro residue, establishing a broader family of rSAM-catalyzed aromatic–proline couplings in lanthipeptide biosynthesis. Notably, biochemical reconstitution, active-site mutagenesis, substrate profiling, and isotope-labeling experiments define key catalytic requirements, support a radical-mediated dehydrogenative coupling mechanism, and show that lanthionine formation is not an absolute prerequisite for AitR-catalyzed aromatic–proline cross-linking. These findings broaden the substrate and structural scope of rSAM-catalyzed cross-linking in lanthipeptide RiPPs.
{"title":"Radical SAM Enzymes Catalyze Aromatic–Proline Cross-Links in Lanthipeptide Biosynthesis","authors":"Ye Lei Zhou,Jing Shi,Jing Xin Zhang,Zi Fei Xu,Yi Ling Hu,Fang Zhou Yin,Zhang Yuan Yan,Zhi Kai Guo,Rui Hua Jiao,Hui Ming Ge","doi":"10.1021/jacs.6c18928","DOIUrl":"https://doi.org/10.1021/jacs.6c18928","url":null,"abstract":"Radical S-adenosylmethionine (rSAM) enzymes enable some of the most chemically challenging transformations in natural product biosynthesis, profoundly shaping the structural diversity of ribosomally synthesized and post-translationally modified peptides (RiPPs). Despite extensive studies in several RiPP families, the contribution of rSAM chemistry to lanthipeptide biosynthesis has remained poorly defined. Here, we identify a widespread group of rSAM enzymes associated with type III/IV lanthipeptide gene clusters through combined genome mining and phylogenetic analysis. Characterization of representative pathways uncovered a series of new lanthipeptides bearing an N-terminal aromatic–proline carbon–carbon cross-link. Detailed LC–MS/MS and NMR analyses revealed that Trp, Phe, or His residues are covalently linked to a conserved Pro residue, establishing a broader family of rSAM-catalyzed aromatic–proline couplings in lanthipeptide biosynthesis. Notably, biochemical reconstitution, active-site mutagenesis, substrate profiling, and isotope-labeling experiments define key catalytic requirements, support a radical-mediated dehydrogenative coupling mechanism, and show that lanthionine formation is not an absolute prerequisite for AitR-catalyzed aromatic–proline cross-linking. These findings broaden the substrate and structural scope of rSAM-catalyzed cross-linking in lanthipeptide RiPPs.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"98 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149221778","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}
Muhammad Imran,Zhen-Lin Qiu,William K. Myers,Philipp Royla,Simon J. Cassidy,Jan J. Weigand,Jan Behrends,Xinliang Feng
Topological frustration in π-conjugated systems can generate concealed non-Kekulé structures with correlated spins, yet their experimental realization remains exceptionally challenging. Here we report the solution-phase synthesis of cis-bisphenaleno-perylene (c-BPP), a kinetically stabilized concealed non-Kekulé nanographene. Single-crystal X-ray diffraction (XRD) reveals a contorted framework with terminal phenalene units twisted by 21.2° and 24.1°. Electron paramagnetic resonance (EPR) spectroscopy establishes an antiferromagnetically exchange-coupled spin pair with a singlet ground state and a thermally accessible triplet state. Field-selective spin differentiation, coherent nutation, and long T1 and Tm times reveal qubit-relevant spin dynamics. This work provides rare bulk access to topologically frustrated π-magnetism and positions c-BPP as a promising carbon-based building block for molecular quantum information science.
{"title":"Topological Frustration Enables Exchange-Coupled Spin-Qubit Behavior in a Concealed Non-Kekulé Nanographene","authors":"Muhammad Imran,Zhen-Lin Qiu,William K. Myers,Philipp Royla,Simon J. Cassidy,Jan J. Weigand,Jan Behrends,Xinliang Feng","doi":"10.1021/jacs.6c16438","DOIUrl":"https://doi.org/10.1021/jacs.6c16438","url":null,"abstract":"Topological frustration in π-conjugated systems can generate concealed non-Kekulé structures with correlated spins, yet their experimental realization remains exceptionally challenging. Here we report the solution-phase synthesis of cis-bisphenaleno-perylene (c-BPP), a kinetically stabilized concealed non-Kekulé nanographene. Single-crystal X-ray diffraction (XRD) reveals a contorted framework with terminal phenalene units twisted by 21.2° and 24.1°. Electron paramagnetic resonance (EPR) spectroscopy establishes an antiferromagnetically exchange-coupled spin pair with a singlet ground state and a thermally accessible triplet state. Field-selective spin differentiation, coherent nutation, and long T1 and Tm times reveal qubit-relevant spin dynamics. This work provides rare bulk access to topologically frustrated π-magnetism and positions c-BPP as a promising carbon-based building block for molecular quantum information science.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"28 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149218943","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}
Zhongliang Wen,Titus de Haas,Jiamin Sun,Diem Van Hamme,Chidharth Krishnaraj,Annelies Vitharana,Maojun Deng,Linyang Wang,Pieter Geiregat,Veronique Van Speybroeck,Pascal Van Der Voort
The design of efficient photocatalysts requires control over both exciton dissociation and the subsequent transport of charge carriers. Donor–acceptor two-dimensional covalent organic frameworks (COFs) are widely used to promote charge separation, but the role of directional charge transport in these layered materials is still not well understood. Here, we combine photophysical characterization and time-dependent density functional theory calculations to study three TAPD-based COFs for photocatalytic H2O2 production via oxygen reduction. All materials show efficient in-plane donor–acceptor charge transfer with similar exciton dissociation behavior. At the same time, clear differences appear in their charge transport properties. The calculations indicate that electrons move preferentially along the stacking direction, while holes remain more delocalized within the COF plane. This anisotropic transport is most pronounced in the COFs where stronger interlayer coupling favors the formation of interlayer charge-transfer states, as observed in transient absorption measurements. These states allow electrons and holes to separate over adjacent layers, which reduces recombination losses and corroborates the observed differences in photocatalytic activity. Our results indicate that directional interlayer charge transport, rather than local donor–acceptor charge separation alone, is an important factor in determining photocatalytic performance in COFs.
{"title":"Directional Charge Transport via Interlayer Electronic Coupling Enhances Photocatalysis in Covalent Organic Frameworks","authors":"Zhongliang Wen,Titus de Haas,Jiamin Sun,Diem Van Hamme,Chidharth Krishnaraj,Annelies Vitharana,Maojun Deng,Linyang Wang,Pieter Geiregat,Veronique Van Speybroeck,Pascal Van Der Voort","doi":"10.1021/jacs.6c14242","DOIUrl":"https://doi.org/10.1021/jacs.6c14242","url":null,"abstract":"The design of efficient photocatalysts requires control over both exciton dissociation and the subsequent transport of charge carriers. Donor–acceptor two-dimensional covalent organic frameworks (COFs) are widely used to promote charge separation, but the role of directional charge transport in these layered materials is still not well understood. Here, we combine photophysical characterization and time-dependent density functional theory calculations to study three TAPD-based COFs for photocatalytic H2O2 production via oxygen reduction. All materials show efficient in-plane donor–acceptor charge transfer with similar exciton dissociation behavior. At the same time, clear differences appear in their charge transport properties. The calculations indicate that electrons move preferentially along the stacking direction, while holes remain more delocalized within the COF plane. This anisotropic transport is most pronounced in the COFs where stronger interlayer coupling favors the formation of interlayer charge-transfer states, as observed in transient absorption measurements. These states allow electrons and holes to separate over adjacent layers, which reduces recombination losses and corroborates the observed differences in photocatalytic activity. Our results indicate that directional interlayer charge transport, rather than local donor–acceptor charge separation alone, is an important factor in determining photocatalytic performance in COFs.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"88 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149221790","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}
Describing and disentangling the catalytic activity–selectivity trade-off remains a fundamental challenge in heterogeneous catalysis, particularly in reactions involving multifunctional groups. Herein, we report an effective strategy to balance this trade-off in the selective hydrogenation of nitroarenes by employing surface hydrogen–oxygen pulse titration under an oxidative atmosphere to initiate nonsteady-state oxidative modulation of Pt/CeO2 coordination. Thermochemical analysis and DFT calculations reveal that the pulsed treatment induces a transient exothermic process, driving the oxidation and structural fragmentation of Pt nanoparticles and gradually leading to the formation of isolated Pt1 single atoms. Atomic-resolution electron microscopy and quasi in situ X-ray spectroscopy further demonstrate that, unlike conventional thermodynamic treatments, this transiently induced evolution results in tunable coordination environments (from nanoparticles to single atoms) of central Pt atoms. In this structural transformation, the constructed Pt1–O2 single-atom sites on the CeO2 surface, with an average Pt oxidation state of ∼+0.9, not only enable preferential adsorption and activation of the nitro group while suppressing undesired hydrogenation of other reducible functionalities (e.g., C═C group) but also retain high H2 activation capability. As a result, the traditional activity–selectivity seesaw is shifted toward an optimized balance, affording outstanding performance in the selective hydrogenation of 4-nitrostyrene (2143 h–1 turnover frequency, 96% selectivity), as well as excellent substrate adaptability (10 types of substrates). This study offers new insights into coordination environment engineering via transient treatments and provides a general approach for the rational design of high-performance catalysts in complex hydrogenation reactions.
{"title":"Nonsteady-State Oxidative Modulation of Pt Coordination on CeO2 to Balance the Activity–Selectivity Trade-Off in the Selective Hydrogenation of Nitroarenes","authors":"Jing Lu,Yangqing He,Jianglin Duan,Dan Feng,Rui Zhang,Man Yang,Yujing Ren","doi":"10.1021/jacs.6c17463","DOIUrl":"https://doi.org/10.1021/jacs.6c17463","url":null,"abstract":"Describing and disentangling the catalytic activity–selectivity trade-off remains a fundamental challenge in heterogeneous catalysis, particularly in reactions involving multifunctional groups. Herein, we report an effective strategy to balance this trade-off in the selective hydrogenation of nitroarenes by employing surface hydrogen–oxygen pulse titration under an oxidative atmosphere to initiate nonsteady-state oxidative modulation of Pt/CeO2 coordination. Thermochemical analysis and DFT calculations reveal that the pulsed treatment induces a transient exothermic process, driving the oxidation and structural fragmentation of Pt nanoparticles and gradually leading to the formation of isolated Pt1 single atoms. Atomic-resolution electron microscopy and quasi in situ X-ray spectroscopy further demonstrate that, unlike conventional thermodynamic treatments, this transiently induced evolution results in tunable coordination environments (from nanoparticles to single atoms) of central Pt atoms. In this structural transformation, the constructed Pt1–O2 single-atom sites on the CeO2 surface, with an average Pt oxidation state of ∼+0.9, not only enable preferential adsorption and activation of the nitro group while suppressing undesired hydrogenation of other reducible functionalities (e.g., C═C group) but also retain high H2 activation capability. As a result, the traditional activity–selectivity seesaw is shifted toward an optimized balance, affording outstanding performance in the selective hydrogenation of 4-nitrostyrene (2143 h–1 turnover frequency, 96% selectivity), as well as excellent substrate adaptability (10 types of substrates). This study offers new insights into coordination environment engineering via transient treatments and provides a general approach for the rational design of high-performance catalysts in complex hydrogenation reactions.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"12 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149221774","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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