Pengbo Ye, Xiangyue Wei, Chengfeng Shen, Xuehui Liu, Shimei Xu, Yu-Zhong Wang
Low-density polyethylene (LDPE) is widely used in packaging applications, but after discarded its environmental impact is a pressing concern due to lacking of effective chemical recycling strategies, especially owing to its chemical inertness and nonpolar nature. To address these challenges, we present a mild iron (III)-catalyzed oxidative upcycling of LDPE in which C-H hydroxylation of LDPE occurs coupled with the growth of methyl short chain branching (Me-SCB) and ethyl short chain branching (Et-SCB). As a result, the resulting products achieve significant improvements in surface wettability, crystallinity and mechanical properties despite a concomitant reduction in molecular weight. C-H…F interactions and σ-π interactions are found between LDPE and the catalyst. Density functional theory (DFT) calculations elucidate the catalytic mechanism that fluorine on the ligand facilitates hydrogen peroxide activation and subsequent deprotonation, leading to the formation of high-valent iron oxo species. The growth of SCB involves the β-scission of C-C bonds and radical-mediated chain-walking mechanism. This work represents a transformative advancement in deep understanding of polyolefin upcycling and opening new approach of polyolefin functionalization and architecture modulation.
{"title":"Iron (III)-catalyzed C-H hydroxylation of low-density polyethylene coupled with short chain branching growth","authors":"Pengbo Ye, Xiangyue Wei, Chengfeng Shen, Xuehui Liu, Shimei Xu, Yu-Zhong Wang","doi":"10.1002/anie.202503405","DOIUrl":"https://doi.org/10.1002/anie.202503405","url":null,"abstract":"Low-density polyethylene (LDPE) is widely used in packaging applications, but after discarded its environmental impact is a pressing concern due to lacking of effective chemical recycling strategies, especially owing to its chemical inertness and nonpolar nature. To address these challenges, we present a mild iron (III)-catalyzed oxidative upcycling of LDPE in which C-H hydroxylation of LDPE occurs coupled with the growth of methyl short chain branching (Me-SCB) and ethyl short chain branching (Et-SCB). As a result, the resulting products achieve significant improvements in surface wettability, crystallinity and mechanical properties despite a concomitant reduction in molecular weight. C-H…F interactions and σ-π interactions are found between LDPE and the catalyst. Density functional theory (DFT) calculations elucidate the catalytic mechanism that fluorine on the ligand facilitates hydrogen peroxide activation and subsequent deprotonation, leading to the formation of high-valent iron oxo species. The growth of SCB involves the β-scission of C-C bonds and radical-mediated chain-walking mechanism. This work represents a transformative advancement in deep understanding of polyolefin upcycling and opening new approach of polyolefin functionalization and architecture modulation.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"43 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857621","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}
Chenchang Ma, Alexander Matler, Shuai Zhu, Thayalan Rajeshkumar, Laurent Maron, Qing Ye
Reactions between Rosenthal’s titanocene (Cp2Ti) and decamethyltitanocene (Cp*2Ti) synthons with various bis(alkynyl)boranes were investigated. A series of titanium-fused boracyclobutenes were obtained through the reaction of the Cp*2Ti synthon with (Me3Si)2NB(CCR)2 or PhB(CCPh)2. This represents the first realization of approaching this structural motif via the rearrangement of bis(alkynyl)boranes within the coordination sphere of a d-block metal. These findings break the previous limitation that the boron substituent must be an amino group. Furthermore, the reaction of the Cp*2Ti synthon with (Me3Si)PhNB(CCPh)2 or (Mes2B)PhNB(CCPh)2 (Mes = 2,4,6-trimethylphenyl) led to the formation of novel tethered metallocene complexes, in which the titanacyclopentadiene structure is linked to one of the cyclopentadienyl groups via a –CH2–BR– bridge. Both experimental and theoretical studies provided insights into an unprecedented reaction mechanism. The process involves the initial formation of an η2-coordinated bis(alkynyl)borane intermediate, which was detected and analyzed by NMR spectroscopy and X-ray diffraction analysis. This intermediate subsequently undergoes either B–Calkynyl bond activation or CMe–H activation of the Cp* ligand, leading to the formation of two distinct types of products.
{"title":"Titanium-Mediated Rearrangement of Bis(alkynyl)boranes: B–C Activation vs C–H Activation","authors":"Chenchang Ma, Alexander Matler, Shuai Zhu, Thayalan Rajeshkumar, Laurent Maron, Qing Ye","doi":"10.1002/anie.202504229","DOIUrl":"https://doi.org/10.1002/anie.202504229","url":null,"abstract":"Reactions between Rosenthal’s titanocene (Cp2Ti) and decamethyltitanocene (Cp*2Ti) synthons with various bis(alkynyl)boranes were investigated. A series of titanium-fused boracyclobutenes were obtained through the reaction of the Cp*2Ti synthon with (Me3Si)2NB(CCR)2 or PhB(CCPh)2. This represents the first realization of approaching this structural motif via the rearrangement of bis(alkynyl)boranes within the coordination sphere of a d-block metal. These findings break the previous limitation that the boron substituent must be an amino group. Furthermore, the reaction of the Cp*2Ti synthon with (Me3Si)PhNB(CCPh)2 or (Mes2B)PhNB(CCPh)2 (Mes = 2,4,6-trimethylphenyl) led to the formation of novel tethered metallocene complexes, in which the titanacyclopentadiene structure is linked to one of the cyclopentadienyl groups via a –CH2–BR– bridge. Both experimental and theoretical studies provided insights into an unprecedented reaction mechanism. The process involves the initial formation of an η2-coordinated bis(alkynyl)borane intermediate, which was detected and analyzed by NMR spectroscopy and X-ray diffraction analysis. This intermediate subsequently undergoes either B–Calkynyl bond activation or CMe–H activation of the Cp* ligand, leading to the formation of two distinct types of products.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"7 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858126","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}
Electrocatalytic nitrate reduction reaction (NITRR) represents a promising approach for ammonia synthesis, but existing application has been constrained by the complex proton-coupled electron transfer and the sluggish kinetics induced by various intermediates. Herein, we synthesized a series of metalized covalent organic frameworks: NiTP−MTAPP MCOFs (M = 2H, Co, Cu and Fe), based on dual redox-active centers: thiophene-substituted Ni-bis(dithiolene) ligand-Ni[C2S2(C4H2SCHO)2]2 and metallic porphyrin. Through regulating the adsorption and desorption of species at the catalytic sites, we have identified the optimal NITRR electrocatalyst: NiTP−CoTAPP MCOF, which achieved the highest Faradaic efficiency (FE) of approximately 85.6% at -0.8 V (vs. RHE) in pure nitrate solution, with an impressive yield rate of 160.2 mmol·h−1·g−1cat. The generation of active hydrogen at [NiS4] sites achieved dynamic equilibrium with the timely hydrogenation reaction at CoN4 sites, effectively suppressing the hydrogen evolution reaction. Moreover, the incorporation of thiophene (TP) groups and metal ions facilitates charge transfer. Density functional theory (DFT) calculations demonstrated the reduction in energy barriers at different catalytic sites. The CoN4−NiS4 system exhibited the optimal adsorption-to-desorption capability and the lowest energy barrier (0.58 eV) for the rate-determining step (*NO → *HNO), which is supported by the moderate d-band center and Bader charge value.
{"title":"Efficient Ammonia Electrosynthesis from Pure Nitrate Reduction via Tuning Bimetallic Sites in Redox-Active Covalent Organic Frameworks","authors":"Zedong Zhang, Miao Wang, Hao-Ran Xing, Xiaocheng Zhou, Lei Gao, Shizheng Chen, Yinjuan Chen, Hui Xu, Wei Li, Shuai Yuan, Cheng-Hui Li, Zhong Jin, Jing-Lin Zuo","doi":"10.1002/anie.202505580","DOIUrl":"https://doi.org/10.1002/anie.202505580","url":null,"abstract":"Electrocatalytic nitrate reduction reaction (NITRR) represents a promising approach for ammonia synthesis, but existing application has been constrained by the complex proton-coupled electron transfer and the sluggish kinetics induced by various intermediates. Herein, we synthesized a series of metalized covalent organic frameworks: NiTP−MTAPP MCOFs (M = 2H, Co, Cu and Fe), based on dual redox-active centers: thiophene-substituted Ni-bis(dithiolene) ligand-Ni[C2S2(C4H2SCHO)2]2 and metallic porphyrin. Through regulating the adsorption and desorption of species at the catalytic sites, we have identified the optimal NITRR electrocatalyst: NiTP−CoTAPP MCOF, which achieved the highest Faradaic efficiency (FE) of approximately 85.6% at -0.8 V (vs. RHE) in pure nitrate solution, with an impressive yield rate of 160.2 mmol·h−1·g−1cat. The generation of active hydrogen at [NiS4] sites achieved dynamic equilibrium with the timely hydrogenation reaction at CoN4 sites, effectively suppressing the hydrogen evolution reaction. Moreover, the incorporation of thiophene (TP) groups and metal ions facilitates charge transfer. Density functional theory (DFT) calculations demonstrated the reduction in energy barriers at different catalytic sites. The CoN4−NiS4 system exhibited the optimal adsorption-to-desorption capability and the lowest energy barrier (0.58 eV) for the rate-determining step (*NO → *HNO), which is supported by the moderate d-band center and Bader charge value.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"12 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857411","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}
Herein, we report the first enantioselective total syntheses of three rearranged ent-trachylobane diterpenoids, (–)-Wallichanol A (1), (–)-Wallichanol B (2) and (–)-Sanguinolane (3), using a 13, 17 and 14 step longest-linear sequences respectively, featuring a novel intramolecular [2+2] cycloaddition to construct the unique pentacyclic framework containing an unprecedented tricyclo[3.3.1.02,7]nonane motif. Other key steps in the synthetic route include a highly challenging, selective alkene reduction via hydrogen atom transfer (HAT), leveraging the thermodynamic preference for a tertiary carbon-centered radical; a Robinson-type annulation to construct the tricyclic terpenoid building block; and applying aerobic oxidation at two distinct points to form α-hydroxy ketones, facilitating the enantioselective syntheses of these diterpenoids.
{"title":"Concise Enantioselective Total Syntheses of Rearranged ent-Trachylobane Diterpenoids (–)-Wallichanols A and B","authors":"Dattatraya H Dethe, Nitin Sharma, Sakshi Juyal","doi":"10.1002/anie.202505766","DOIUrl":"https://doi.org/10.1002/anie.202505766","url":null,"abstract":"Herein, we report the first enantioselective total syntheses of three rearranged ent-trachylobane diterpenoids, (–)-Wallichanol A (1), (–)-Wallichanol B (2) and (–)-Sanguinolane (3), using a 13, 17 and 14 step longest-linear sequences respectively, featuring a novel intramolecular [2+2] cycloaddition to construct the unique pentacyclic framework containing an unprecedented tricyclo[3.3.1.02,7]nonane motif. Other key steps in the synthetic route include a highly challenging, selective alkene reduction via hydrogen atom transfer (HAT), leveraging the thermodynamic preference for a tertiary carbon-centered radical; a Robinson-type annulation to construct the tricyclic terpenoid building block; and applying aerobic oxidation at two distinct points to form α-hydroxy ketones, facilitating the enantioselective syntheses of these diterpenoids.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"24 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862577","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}
Seongwon Park, Jaeduk Byun, Seong-hun Lee, Tae Joo Shin, Byoung-Ki Cho
Ferroelectric columnar liquid crystals (FCLCs) with switchable bistable axial polarizations are promising candidates for high-density ferroelectric random-access memory (FeRAM). However, FCLCs simultaneously exhibiting uniform polarization arrangement and ferroelectric switching at room temperature (RT) remain elusive. Herein, we report an RT-operable FCLC based on a C3-symmetric star-shaped mesogen with polar linkers. Two CLCs, 1 and 2, were synthesized incorporating 1,2,3-triazole and amide linkers, respectively. 1 undergoes a ferroelectric-to-paraelectric transition accompanied by a structural change from a helical to a non-helical columnar phase. Notably, the ferroelectric switching is operable down to RT, with complete retention of its axial macrodipole after removal of the electric field. In contrast, 2 forms only a non-helical columnar LC phase, displaying paraelectric behavior. The contrasting self-assembly and dielectric properties are attributed to the differences in the polar unit size. This study demonstrates that the mesogen extension with a bulky 1,2,3-triazole linker enables the realization of a FCLC operable at RT, offering significant potential for high-density FeRAM applications.
{"title":"A Helical Columnar Liquid Crystal Exhibiting Both Polarization Retention and Ferroelectric Switching at Room Temperature","authors":"Seongwon Park, Jaeduk Byun, Seong-hun Lee, Tae Joo Shin, Byoung-Ki Cho","doi":"10.1002/anie.202507574","DOIUrl":"https://doi.org/10.1002/anie.202507574","url":null,"abstract":"Ferroelectric columnar liquid crystals (FCLCs) with switchable bistable axial polarizations are promising candidates for high-density ferroelectric random-access memory (FeRAM). However, FCLCs simultaneously exhibiting uniform polarization arrangement and ferroelectric switching at room temperature (RT) remain elusive. Herein, we report an RT-operable FCLC based on a C3-symmetric star-shaped mesogen with polar linkers. Two CLCs, 1 and 2, were synthesized incorporating 1,2,3-triazole and amide linkers, respectively. 1 undergoes a ferroelectric-to-paraelectric transition accompanied by a structural change from a helical to a non-helical columnar phase. Notably, the ferroelectric switching is operable down to RT, with complete retention of its axial macrodipole after removal of the electric field. In contrast, 2 forms only a non-helical columnar LC phase, displaying paraelectric behavior. The contrasting self-assembly and dielectric properties are attributed to the differences in the polar unit size. This study demonstrates that the mesogen extension with a bulky 1,2,3-triazole linker enables the realization of a FCLC operable at RT, offering significant potential for high-density FeRAM applications.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"171 1 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862584","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}
The electrochemical activation of light alkanes into value-added products represents a promising pathway for sustainable chemical synthesis and the storage of renewable energy. In this study, we introduce an electrochemically promoted system that employs copper plates as electrode and oxygen as oxidant, capable of converting ethane into ethylene and acetic acid with production rates of 6.9 and 6.2 µmol·cm−2Cu·h−1, respectively, with a combined selectivity exceeding 92%, under ambient conditions. Additionally, this system can convert propane to propylene at a rate of 11.6 µmol·cm−2Cu·h−1, with selectivity reaching up to 86%. A 10-hour run with ethane demonstrates consistent production of ethylene and acetic acid, with a sustained selectivity above 96% and achieving an acetic acid concentration of 19 mM. In situ spectroscopic analysis reveals the active surface and a critical reaction intermediate. Combining with partial pressure dependence study and Density Functional Theory (DFT) calculations, we propose a potential reaction mechanism involving the competitive adsorption of oxygen and alkane producing an alkyl group as a key reaction step in the reaction process.
{"title":"Electrochemically Promoted Activation of Light Alkanes at Ambient Conditions","authors":"Qi Lu, Wenxuan Liu, Hsien-Chin Li, Chunsong Li, Wei-Sen Chen, Haochen Zhang, Bingjun Xu, Mu-Jeng Cheng","doi":"10.1002/anie.202507417","DOIUrl":"https://doi.org/10.1002/anie.202507417","url":null,"abstract":"The electrochemical activation of light alkanes into value-added products represents a promising pathway for sustainable chemical synthesis and the storage of renewable energy. In this study, we introduce an electrochemically promoted system that employs copper plates as electrode and oxygen as oxidant, capable of converting ethane into ethylene and acetic acid with production rates of 6.9 and 6.2 µmol·cm−2Cu·h−1, respectively, with a combined selectivity exceeding 92%, under ambient conditions. Additionally, this system can convert propane to propylene at a rate of 11.6 µmol·cm−2Cu·h−1, with selectivity reaching up to 86%. A 10-hour run with ethane demonstrates consistent production of ethylene and acetic acid, with a sustained selectivity above 96% and achieving an acetic acid concentration of 19 mM. In situ spectroscopic analysis reveals the active surface and a critical reaction intermediate. Combining with partial pressure dependence study and Density Functional Theory (DFT) calculations, we propose a potential reaction mechanism involving the competitive adsorption of oxygen and alkane producing an alkyl group as a key reaction step in the reaction process.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"15 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857409","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}
Pore engineering through chemical environment modification is vital for developing industrial porous materials. Understanding the effects of substitutions in isoreticular porous coordination‐polymers—such as steric hindrance, vibrational capabilities, electronic influences, and hydropathy—is key to elucidating structure‐property relationships. However, accurately assessing the impact of functional groups on properties remains challenging due to limitations in current methodologies. In this study, we designed a series of titanium‐isophthalate coordination‐polymers with various functional groups to regulate pore characteristics and structural dimensionality. The unique spatial arrangement and electronic distribution of isophthalate and its functional groups provide an ideal platform to address these challenges. We conducted extensive investigations combining experimental methods with computational simulations to explore how pore engineering affects adsorptive separation and photoresponsive behavior in these compounds. Our findings not only tackle the synthesis challenge of isostructural titanium‐coordination polymers but also offer new insights into understanding structure‐property relationships achieved through modulation of their chemical environments.
{"title":"Pore engineering in isoreticular titanium‐isophthalate coordination polymers","authors":"Sujing WANG, Qingqing Yan, Chenyang Nie, Valentin Diez Cabanes, Fu-An Guo, Yafei Du, Hailun Xia, Hao Wang, Guillaume Maurin, Peng Guo","doi":"10.1002/anie.202503618","DOIUrl":"https://doi.org/10.1002/anie.202503618","url":null,"abstract":"Pore engineering through chemical environment modification is vital for developing industrial porous materials. Understanding the effects of substitutions in isoreticular porous coordination‐polymers—such as steric hindrance, vibrational capabilities, electronic influences, and hydropathy—is key to elucidating structure‐property relationships. However, accurately assessing the impact of functional groups on properties remains challenging due to limitations in current methodologies. In this study, we designed a series of titanium‐isophthalate coordination‐polymers with various functional groups to regulate pore characteristics and structural dimensionality. The unique spatial arrangement and electronic distribution of isophthalate and its functional groups provide an ideal platform to address these challenges. We conducted extensive investigations combining experimental methods with computational simulations to explore how pore engineering affects adsorptive separation and photoresponsive behavior in these compounds. Our findings not only tackle the synthesis challenge of isostructural titanium‐coordination polymers but also offer new insights into understanding structure‐property relationships achieved through modulation of their chemical environments.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"13 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853293","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}
Stuart A. Macgregor, Pablo Domingo-Legarda, Samuel E. Neale, Ambre Carpentier, Claire L. McMullin, Michael Findlay, Igor Larrosa
The mechanism of Ru-catalysed N-directed C-H ortho-arylation with haloarenes has been under intense scrutiny over the last decade, with conflicting proposals concerning the relevance of various catalytic intermediates and the nature of the key steps. This work presents experimental and computational studies that address these long-standing questions. Stoichiometric, catalytic and mechanistic kinetic studies, supported by DFT calculations, reveal that bis-cyclometallated ruthenium species are key intermediates in these reactions. These studies also show that oxidative addition with bromoarenes proceeds via a concerted oxidative addition pathway, as demonstrated by DFT and experimental kinetic orders. Bromoarene activation does not proceed at mono-cyclometalated species. In the catalytic process, zero order kinetics are observed on both reaction substrates, an observation that is rationalised by DFT calculations which predict a rate-limiting step within the product-release stage. These results showcase how detailed experimental and DFT studies can combine to probe mechanistic questions, as well as resolving opposing views around the mechanism of these Ru-catalysed arylations that form the basis of promising mild C-H functionalisations.
{"title":"The Mechanism of Ru-catalyzed Directed C–H Arylation of Arenes: the Key Role of Bis-Cyclometalated Intermediates.","authors":"Stuart A. Macgregor, Pablo Domingo-Legarda, Samuel E. Neale, Ambre Carpentier, Claire L. McMullin, Michael Findlay, Igor Larrosa","doi":"10.1002/anie.202506707","DOIUrl":"https://doi.org/10.1002/anie.202506707","url":null,"abstract":"The mechanism of Ru-catalysed N-directed C-H ortho-arylation with haloarenes has been under intense scrutiny over the last decade, with conflicting proposals concerning the relevance of various catalytic intermediates and the nature of the key steps. This work presents experimental and computational studies that address these long-standing questions. Stoichiometric, catalytic and mechanistic kinetic studies, supported by DFT calculations, reveal that bis-cyclometallated ruthenium species are key intermediates in these reactions. These studies also show that oxidative addition with bromoarenes proceeds via a concerted oxidative addition pathway, as demonstrated by DFT and experimental kinetic orders. Bromoarene activation does not proceed at mono-cyclometalated species. In the catalytic process, zero order kinetics are observed on both reaction substrates, an observation that is rationalised by DFT calculations which predict a rate-limiting step within the product-release stage. These results showcase how detailed experimental and DFT studies can combine to probe mechanistic questions, as well as resolving opposing views around the mechanism of these Ru-catalysed arylations that form the basis of promising mild C-H functionalisations.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"23 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853656","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}
Hao Yang Lin, Wen Jing Li, Miao Yu Lin, Hao Guan Xu, Song Ru Fang, Yao Lv, Wenbo Li, Jianwei Guo, Huai Qin Fu, Hai Yang Yuan, Chenghua Sun, Sheng Dai, Peng Fei Liu, Huagui Yang
Transition metal nitrides are promising conductive support materials in oxygen evolution reaction (OER), whereas it is unclear if their electrochemical oxidation during prolonged test would affect the OER catalysts. Herein, we demonstrate that the leaching-induced Ti trapping effect from TiN supports effectively stabilizes the electrochemically oxidized amorphous IrOx catalyst. Structural characterizations reveal that the TiN support experiences severe leaching during OER test, leaving minor amounts of Ti-O species trapping on IrOx clusters, which mitigate the overoxidation of Ir(III) species and elongate the Ir-O bonds. This leads to 70% reduction of lattice oxygen oxidation and the substantially reduced Ir leaching. Additionally, self-thickening of the catalyst layers is found during proton exchange membrane water electrolysis (PEMWE), enabling an ultralow catalyst loading of 87 μgIr cm-2 to obtain a stable operation at 1.0 A cm-2 for 500 h. This work deepens the understanding of TiN supported catalysts for long-term stable OER electrocatalysis.
过渡金属氮化物是氧进化反应（OER）中很有前景的导电支撑材料，但其在长期试验过程中的电化学氧化是否会影响 OER 催化剂尚不清楚。在此，我们证明了 TiN 支撑材料的浸出诱导钛捕集效应可有效稳定电化学氧化的非晶态 IrOx 催化剂。结构表征结果表明，在 OER 测试过程中，TiN 支撑物经历了严重的浸出，在 IrOx 簇上留下了少量的 Ti-O 物种捕集，从而减轻了 Ir(III) 物种的过氧化反应并延长了 Ir-O 键。这导致晶格氧氧化减少了 70%，并大大降低了 Ir 的沥滤。此外，在质子交换膜水电解（PEMWE）过程中，催化剂层出现了自增厚现象，使催化剂的超低负载量（87 μgIr cm-2）得以在 1.0 A cm-2 的条件下稳定运行 500 小时。
{"title":"Leaching-Induced Ti Trapping Stabilizes Amorphous IrOx for Proton Exchange Membrane Water Electrolysis","authors":"Hao Yang Lin, Wen Jing Li, Miao Yu Lin, Hao Guan Xu, Song Ru Fang, Yao Lv, Wenbo Li, Jianwei Guo, Huai Qin Fu, Hai Yang Yuan, Chenghua Sun, Sheng Dai, Peng Fei Liu, Huagui Yang","doi":"10.1002/anie.202504212","DOIUrl":"https://doi.org/10.1002/anie.202504212","url":null,"abstract":"Transition metal nitrides are promising conductive support materials in oxygen evolution reaction (OER), whereas it is unclear if their electrochemical oxidation during prolonged test would affect the OER catalysts. Herein, we demonstrate that the leaching-induced Ti trapping effect from TiN supports effectively stabilizes the electrochemically oxidized amorphous IrOx catalyst. Structural characterizations reveal that the TiN support experiences severe leaching during OER test, leaving minor amounts of Ti-O species trapping on IrOx clusters, which mitigate the overoxidation of Ir(III) species and elongate the Ir-O bonds. This leads to 70% reduction of lattice oxygen oxidation and the substantially reduced Ir leaching. Additionally, self-thickening of the catalyst layers is found during proton exchange membrane water electrolysis (PEMWE), enabling an ultralow catalyst loading of 87 μgIr cm-2 to obtain a stable operation at 1.0 A cm-2 for 500 h. This work deepens the understanding of TiN supported catalysts for long-term stable OER electrocatalysis.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"11 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853837","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}
Huaxin Liu, Fangjun Zhu, Yinghao Zhang, Yuming Liu, Yi Zhang, Wentao Deng, Guoqiang Zou, Hongshuai Hou, Xiaobo Ji
Low ionic conductivity, poor mechanical strength and unstable interface structure are still the main factors hindering the practical application of polymer solid‐state lithium metal batteries (SSLMBs). In this work, we have developed a unique composite filler (LLZTOCDs) for solid polymer electrolytes to address these challenges through synergistic regulation of multi‐interface chemistry. The LLZTOCDs is prepared via thermal treatment of N, S, F‐codoped carbon dots (NSFCDs) and Li6.5La3Zr1.5Ta0.5O12 (LLZTO) inorganic electrolyte, here the detrimental Li2CO3 on the LLZTO surface is converted into a fast ion‐conducting and an electron‐insulating interlayer of LiF and Li3N, and the carbon dots self‐assemble into a functional organophilic coating on the outermost layer, which acts as a bridge between the LLZTO and the polymer. This unique structure enhances the compatibility and ion‐exchange kinetics between the LLZTOCDs and the polymer, significantly improving the mechanical strength and Li+ transport. Additionally, the oxygen vacancies formed in‐situ at the LLZTOCDs interface provide an anion confinement effect, increasing lithium salt dissociation and enhancing the Li+ transference number to 0.85. Therefore, the solid battery constructed with LLZTOCDs exhibits excellent electrochemical stability, long‐cycle life, and high ionic conductivity (1.96 × 10−4 S cm‐1 at 25 °C), providing a feasible strategy for practical applications.
{"title":"Synergistic Regulation of Multi‐interface Chemistry by Functional Carbon Dots for High‐Performance Composite Solid Electrolytes","authors":"Huaxin Liu, Fangjun Zhu, Yinghao Zhang, Yuming Liu, Yi Zhang, Wentao Deng, Guoqiang Zou, Hongshuai Hou, Xiaobo Ji","doi":"10.1002/anie.202505230","DOIUrl":"https://doi.org/10.1002/anie.202505230","url":null,"abstract":"Low ionic conductivity, poor mechanical strength and unstable interface structure are still the main factors hindering the practical application of polymer solid‐state lithium metal batteries (SSLMBs). In this work, we have developed a unique composite filler (LLZTOCDs) for solid polymer electrolytes to address these challenges through synergistic regulation of multi‐interface chemistry. The LLZTOCDs is prepared via thermal treatment of N, S, F‐codoped carbon dots (NSFCDs) and Li6.5La3Zr1.5Ta0.5O12 (LLZTO) inorganic electrolyte, here the detrimental Li2CO3 on the LLZTO surface is converted into a fast ion‐conducting and an electron‐insulating interlayer of LiF and Li3N, and the carbon dots self‐assemble into a functional organophilic coating on the outermost layer, which acts as a bridge between the LLZTO and the polymer. This unique structure enhances the compatibility and ion‐exchange kinetics between the LLZTOCDs and the polymer, significantly improving the mechanical strength and Li+ transport. Additionally, the oxygen vacancies formed in‐situ at the LLZTOCDs interface provide an anion confinement effect, increasing lithium salt dissociation and enhancing the Li+ transference number to 0.85. Therefore, the solid battery constructed with LLZTOCDs exhibits excellent electrochemical stability, long‐cycle life, and high ionic conductivity (1.96 × 10−4 S cm‐1 at 25 °C), providing a feasible strategy for practical applications.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"41 1","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853601","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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