Perylene diimides (PDIs) and their derivatives represent a kind of most promising photocatalytic materials due to their strong visible light absorption, ease of functionalization, excellent thermal/photostability, as well as tunable electronic structures and energy levels. However, several challenges persist in the development of PDI photocatalysts, including low electron–hole separation efficiency, slow charge transfer, and rapid carrier recombination. In this perspective, we focus on enhancing the performance of PDI photocatalysts through a molecular design. We provide a comprehensive overview of various improvement strategies: (1) precise modulation of molecular dipole moments by altering the polarity of side chains to strengthen the built-in electric field, (2) utilization of steric hindrance and noncovalent interactions of side chains to construct nanoscale, highly ordered supramolecular nanostructures, (3) modification of the perylene core to adjust molecular energy levels and increase the number of active sites, (4) integration of PDI with various semiconductors or metals to form composite systems that enhance the interfacial built-in electric field or create extensive delocalized charge channels, and (5) selection of suitable linker groups to build polymer photocatalysts with large dipole moments. These strategies can facilitate the separation and migration of photogenerated carriers in PDI photocatalysts, eventually boosting their photocatalytic efficiency. The relationship between molecular structure and photocatalytic performance, particularly in the context of photocatalytic degradation and water splitting, is examined in detail. Finally, the future prospects and challenges of PDI photocatalysts are thoroughly discussed.
{"title":"Molecular Design of Perylene Diimide Derivatives for Photocatalysis","authors":"Zibin Li, Feng Liu, Yanrong Lu, Jiatong Hu, Jiajing Feng, Hong Shang, Bing Sun, Wei Jiang","doi":"10.1021/acscatal.4c07066","DOIUrl":"https://doi.org/10.1021/acscatal.4c07066","url":null,"abstract":"Perylene diimides (PDIs) and their derivatives represent a kind of most promising photocatalytic materials due to their strong visible light absorption, ease of functionalization, excellent thermal/photostability, as well as tunable electronic structures and energy levels. However, several challenges persist in the development of PDI photocatalysts, including low electron–hole separation efficiency, slow charge transfer, and rapid carrier recombination. In this perspective, we focus on enhancing the performance of PDI photocatalysts through a molecular design. We provide a comprehensive overview of various improvement strategies: (1) precise modulation of molecular dipole moments by altering the polarity of side chains to strengthen the built-in electric field, (2) utilization of steric hindrance and noncovalent interactions of side chains to construct nanoscale, highly ordered supramolecular nanostructures, (3) modification of the perylene core to adjust molecular energy levels and increase the number of active sites, (4) integration of PDI with various semiconductors or metals to form composite systems that enhance the interfacial built-in electric field or create extensive delocalized charge channels, and (5) selection of suitable linker groups to build polymer photocatalysts with large dipole moments. These strategies can facilitate the separation and migration of photogenerated carriers in PDI photocatalysts, eventually boosting their photocatalytic efficiency. The relationship between molecular structure and photocatalytic performance, particularly in the context of photocatalytic degradation and water splitting, is examined in detail. Finally, the future prospects and challenges of PDI photocatalysts are thoroughly discussed.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"144 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988231","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}
Pub Date : 2025-01-17DOI: 10.1021/acscatal.4c07496
Yu Gao, Yonghui Fan, Hao Zhang, Peerapol Pornsetmetakul, Brahim Mezari, Jorden Wagemakers, Mahesh Ramakrishnan, Konstantin Klementiev, Nikolay Kosinov, Emiel J. M. Hensen
The catalytic conversion of carbon dioxide (CO2) to methanol over Cu/ZnO catalysts is expected to become valuable for recycling CO2. The nature of the Cu–Zn interplay remains a subject of intense debate due to many different Zn species encountered in Cu/ZnO catalysts. In this study, we designed a Cu–Zn catalyst by ion-exchanging Cu into CIT-6, a crystalline microporous zincosilicate with the BEA* topology. The catalyst exhibited high and stable CO2 hydrogenation rate to methanol. In contrast, its aluminosilicate counterparts Cu-Beta and CuZn-Beta mainly converted CO2 to CO. Operando X-ray absorption spectroscopy combined with X-ray diffraction confirmed the stability of Zn cations in the zincosilicate framework during reduction in H2 and reaction in CO2/H2. The active phase consisted of highly dispersed Cu particles. These particles located near isolated Zn2+ species represent a different type of active site for methanol synthesis than the active phases proposed for Cu–Zn catalysts, such as Cu–Zn alloy particles and Cu particles decorated with ZnOx. In situ IR spectroscopy showed the formation of Zn-formate species during CO2 hydrogenation, indicating that Zn2+ ions stabilize formate as a reaction intermediate in the hydrogenation of CO2 to methanol.
{"title":"Stable CO2 Hydrogenation to Methanol by Cu Interacting with Isolated Zn Cations in Zincosilicate CIT-6","authors":"Yu Gao, Yonghui Fan, Hao Zhang, Peerapol Pornsetmetakul, Brahim Mezari, Jorden Wagemakers, Mahesh Ramakrishnan, Konstantin Klementiev, Nikolay Kosinov, Emiel J. M. Hensen","doi":"10.1021/acscatal.4c07496","DOIUrl":"https://doi.org/10.1021/acscatal.4c07496","url":null,"abstract":"The catalytic conversion of carbon dioxide (CO<sub>2</sub>) to methanol over Cu/ZnO catalysts is expected to become valuable for recycling CO<sub>2</sub>. The nature of the Cu–Zn interplay remains a subject of intense debate due to many different Zn species encountered in Cu/ZnO catalysts. In this study, we designed a Cu–Zn catalyst by ion-exchanging Cu into CIT-6, a crystalline microporous zincosilicate with the BEA* topology. The catalyst exhibited high and stable CO<sub>2</sub> hydrogenation rate to methanol. In contrast, its aluminosilicate counterparts Cu-Beta and CuZn-Beta mainly converted CO<sub>2</sub> to CO. <i>Operando</i> X-ray absorption spectroscopy combined with X-ray diffraction confirmed the stability of Zn cations in the zincosilicate framework during reduction in H<sub>2</sub> and reaction in CO<sub>2</sub>/H<sub>2</sub>. The active phase consisted of highly dispersed Cu particles. These particles located near isolated Zn<sup>2+</sup> species represent a different type of active site for methanol synthesis than the active phases proposed for Cu–Zn catalysts, such as Cu–Zn alloy particles and Cu particles decorated with ZnO<sub><i>x</i></sub>. In situ IR spectroscopy showed the formation of Zn-formate species during CO<sub>2</sub> hydrogenation, indicating that Zn<sup>2+</sup> ions stabilize formate as a reaction intermediate in the hydrogenation of CO<sub>2</sub> to methanol.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"2 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988232","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 efficiency of the oxygen evolution reaction (OER) in acidic media is severely limited by the poor stability, low activity, and high cost of available catalysts. Enhancing intrinsic activity while maintaining stability and reducing reliance on precious metals is crucial. The typical adsorbate evolution mechanism (AEM) leads to high overpotentials and low activity, making the transition to alternative mechanisms, such as the lattice oxygen mechanism (LOM) or oxide path mechanism (OPM), highly desirable due to their lower overpotentials. Here, we combine density functional theory (DFT) calculations with experimental validation to enhance the activity and stability of β-MnO2 via co-substitution with ruthenium (Ru) and iridium (Ir), enabling the transition from AEM to OPM. DFT calculations reveal that AEM is hindered by the weak nucleophilicity of water, while LOM suffers from high kinetic barriers due to structural distortions. In contrast, OPM demonstrates a significantly lower kinetic barrier, facilitated by the synergistic interaction between Ru and Ir. Experimentally, IrRuMnOx was synthesized through co-precipitation and hydrothermal methods, showing an 80-fold improvement in mass activity and a 96-fold increase in stability compared to commercial IrO2, with minimal noble metal leaching, as confirmed by inductively coupled plasma optical emission spectroscopy (ICP-OES). IrRuMnOx exhibited an ultralow overpotential of 475 mV at 1 A·cm–2 and a Tafel slope of 44.26 mV·dec–1 in 0.5 M H2SO4, maintaining stable performance for over 100 h. Moreover, the IrRuMnOx-based membrane electrode, with a low Ir loading of 0.075 mgIr·cm–2, achieved remarkable current densities of 1.0 A·cm–2 at 1.66 V and 2.0 A·cm–2 at 1.91 V at 80 °C. This performance surpasses that of both unsupported and conventional supported Ir-based catalysts at comparable Ir loading levels. This study offers critical insights into OER mechanisms in acidic media and paves the way for developing efficient and durable OER electrocatalysts for hydrogen production.
{"title":"Rational Design of β-MnO2 via Ir/Ru Co-substitution for Enhanced Oxygen Evolution Reaction in Acidic Media","authors":"Runxu Deng, Feng Liu, Shixin Gao, Zhenwei Xia, Runjie Wu, Jincheng Kong, Jin Yang, Jiahao Wen, Xiao Zhang, Chade Lv, Yuhao Wang, Xiaoguang Li, Zheng Wang","doi":"10.1021/acscatal.4c05989","DOIUrl":"https://doi.org/10.1021/acscatal.4c05989","url":null,"abstract":"The efficiency of the oxygen evolution reaction (OER) in acidic media is severely limited by the poor stability, low activity, and high cost of available catalysts. Enhancing intrinsic activity while maintaining stability and reducing reliance on precious metals is crucial. The typical adsorbate evolution mechanism (AEM) leads to high overpotentials and low activity, making the transition to alternative mechanisms, such as the lattice oxygen mechanism (LOM) or oxide path mechanism (OPM), highly desirable due to their lower overpotentials. Here, we combine density functional theory (DFT) calculations with experimental validation to enhance the activity and stability of β-MnO<sub>2</sub> via co-substitution with ruthenium (Ru) and iridium (Ir), enabling the transition from AEM to OPM. DFT calculations reveal that AEM is hindered by the weak nucleophilicity of water, while LOM suffers from high kinetic barriers due to structural distortions. In contrast, OPM demonstrates a significantly lower kinetic barrier, facilitated by the synergistic interaction between Ru and Ir. Experimentally, IrRuMnO<sub><i>x</i></sub> was synthesized through co-precipitation and hydrothermal methods, showing an 80-fold improvement in mass activity and a 96-fold increase in stability compared to commercial IrO<sub>2</sub>, with minimal noble metal leaching, as confirmed by inductively coupled plasma optical emission spectroscopy (ICP-OES). IrRuMnO<sub><i>x</i></sub> exhibited an ultralow overpotential of 475 mV at 1 A·cm<sup>–2</sup> and a Tafel slope of 44.26 mV·dec<sup>–1</sup> in 0.5 M H<sub>2</sub>SO<sub>4</sub>, maintaining stable performance for over 100 h. Moreover, the IrRuMnO<sub><i>x</i></sub>-based membrane electrode, with a low Ir loading of 0.075 mg<sub>Ir</sub>·cm<sup>–2</sup>, achieved remarkable current densities of 1.0 A·cm<sup>–2</sup> at 1.66 V and 2.0 A·cm<sup>–2</sup> at 1.91 V at 80 °C. This performance surpasses that of both unsupported and conventional supported Ir-based catalysts at comparable Ir loading levels. This study offers critical insights into OER mechanisms in acidic media and paves the way for developing efficient and durable OER electrocatalysts for hydrogen production.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"116 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988229","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}
Pub Date : 2025-01-17DOI: 10.1021/acscatal.4c05781
Xiaomei Liu, Jun Wang, Chengbo Ma, Shuai Li, Huanyu Fu, Ning Li, Yang Li, Xiaobin Fan, Wenchao Peng
Noble-metal alloys are high-efficiency two-electron oxygen reduction reaction (2e– ORR) catalysts for the electrochemical production of H2O2. However, the development of noble-metal alloys for H2O2 production is still in a bottleneck period due to their high cost, toxicity, low atom utilization, and limited reactivity. To solve these dilemmas of noble-metal alloys, developing non-noble alloys can be an alternative. Herein, non-noble BiNi alloys with a uniform diameter of ∼11 nm supported on carbon nanosheets (BiNi/C) are synthesized by a hydrothermal-pyrolysis method. The BiNi/C material exhibits high 2e– ORR performance with an onset potential of 0.76 V vs RHE and a selectivity of ∼98% in 0.1 M KOH. The H-cell tests deliver a high H2O2 yield of ∼17 mM within 2 h at 0.4 V vs RHE. The synthesized H2O2 is then used in a fixed-bed Fenton process, and the degradation efficiencies of RhB and BPA maintain at 100% and ∼95% within 10 h, respectively. Theoretical calculations reveal that Bi can regulate the electronic structure of Ni in BiNi alloys through the “dual-isolation” effect of physical and electronic isolation. The adsorption energy for *OOH is thus deceased, and side-on adsorption of *OOH on Ni sites is achieved. Furthermore, the Bi atom itself with the lowest overpotential can also serve as a high active site for H2O2 generation due to the dual-isolation effect. Our study provides guidance for the synthesis of non-noble alloy catalysts for 2e– ORR with high activity and selectivity.
{"title":"Dual-Isolation Effect of Bismuth in Non-Noble BiNi Alloys for Enhanced Performance in H2O2 Electrosynthesis","authors":"Xiaomei Liu, Jun Wang, Chengbo Ma, Shuai Li, Huanyu Fu, Ning Li, Yang Li, Xiaobin Fan, Wenchao Peng","doi":"10.1021/acscatal.4c05781","DOIUrl":"https://doi.org/10.1021/acscatal.4c05781","url":null,"abstract":"Noble-metal alloys are high-efficiency two-electron oxygen reduction reaction (2e<sup>–</sup> ORR) catalysts for the electrochemical production of H<sub>2</sub>O<sub>2</sub>. However, the development of noble-metal alloys for H<sub>2</sub>O<sub>2</sub> production is still in a bottleneck period due to their high cost, toxicity, low atom utilization, and limited reactivity. To solve these dilemmas of noble-metal alloys, developing non-noble alloys can be an alternative. Herein, non-noble BiNi alloys with a uniform diameter of ∼11 nm supported on carbon nanosheets (BiNi/C) are synthesized by a hydrothermal-pyrolysis method. The BiNi/C material exhibits high 2e<sup>–</sup> ORR performance with an onset potential of 0.76 V vs RHE and a selectivity of ∼98% in 0.1 M KOH. The H-cell tests deliver a high H<sub>2</sub>O<sub>2</sub> yield of ∼17 mM within 2 h at 0.4 V vs RHE. The synthesized H<sub>2</sub>O<sub>2</sub> is then used in a fixed-bed Fenton process, and the degradation efficiencies of RhB and BPA maintain at 100% and ∼95% within 10 h, respectively. Theoretical calculations reveal that Bi can regulate the electronic structure of Ni in BiNi alloys through the “dual-isolation” effect of physical and electronic isolation. The adsorption energy for *OOH is thus deceased, and side-on adsorption of *OOH on Ni sites is achieved. Furthermore, the Bi atom itself with the lowest overpotential can also serve as a high active site for H<sub>2</sub>O<sub>2</sub> generation due to the dual-isolation effect. Our study provides guidance for the synthesis of non-noble alloy catalysts for 2e<sup>–</sup> ORR with high activity and selectivity.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"30 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988392","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 development of highly active perovskite-based catalysts for the oxidation of volatile organic chemicals (VOCs) has drawn a great deal of attention. A-site defect regulation is found to be effective to improve the catalytic performance, but the relationship between structure variation and catalytic activity has not been clearly unveiled. Herein, this issue was interpreted by the variation of physicochemical properties and electronic structure (O p-band center). An in situ one-step calcination method with NH4HCO3 addition was adopted to prepare a series of A-site-deficient LaCoO3 perovskites (LxCO), which were characterized by XRD, TEM, EELS, ESR, XPS, UPS, H2-TPR, and O2-TPD and catalytic test toward toluene oxidation. The catalytic activity displayed a volcano-type relationship with an addition amount of NH4HCO3. The electronic structure determined the reducibility and active oxygen content and accordingly affected the catalytic activity of LxCO. The obtained results provide theoretical and technical support for the design of efficient VOC oxidation catalysts.
{"title":"Effect of A-Site Defects on the Catalytic Activity of Perovskite LaCoO3: Insights from the Electronic Structure","authors":"Hanlin Chen, Xiaoliang Liang, Zijuan You, Fuding Tan, Jingwen Zhou, Xiaoju Lin, Meiqin Chen, Peng Liu, Yiping Yang, Suhua Wang, Steven L. Suib","doi":"10.1021/acscatal.4c06142","DOIUrl":"https://doi.org/10.1021/acscatal.4c06142","url":null,"abstract":"The development of highly active perovskite-based catalysts for the oxidation of volatile organic chemicals (VOCs) has drawn a great deal of attention. A-site defect regulation is found to be effective to improve the catalytic performance, but the relationship between structure variation and catalytic activity has not been clearly unveiled. Herein, this issue was interpreted by the variation of physicochemical properties and electronic structure (O p-band center). An <i>in situ</i> one-step calcination method with NH<sub>4</sub>HCO<sub>3</sub> addition was adopted to prepare a series of A-site-deficient LaCoO<sub>3</sub> perovskites (L<sub><i>x</i></sub>CO), which were characterized by XRD, TEM, EELS, ESR, XPS, UPS, H<sub>2</sub>-TPR, and O<sub>2</sub>-TPD and catalytic test toward toluene oxidation. The catalytic activity displayed a volcano-type relationship with an addition amount of NH<sub>4</sub>HCO<sub>3</sub>. The electronic structure determined the reducibility and active oxygen content and accordingly affected the catalytic activity of L<sub><i>x</i></sub>CO. The obtained results provide theoretical and technical support for the design of efficient VOC oxidation catalysts.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"55 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988230","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}
Pub Date : 2025-01-16DOI: 10.1021/acscatal.4c06972
Janko Čivić, Iñaki Tuñón, Jeremy N. Harvey
Stearoyl-CoA desaturase (SCD1) plays an important role in the metabolism of fatty acids and is a promising therapeutic target. However, the underlying mechanism of SCD1, as well as other transmembrane nonheme diiron enzymes, remains poorly understood. This study builds upon a previous density functional theory (DFT) cluster model study which proposed a potential reactive intermediate of SCD1. We assessed its dynamical properties by employing classical molecular dynamics (MD) simulations. The simulations revealed that the proposed intermediate lacks the ability to form a favorable reactive complex with stearoyl-CoA, highlighting the significance of a conserved asparagine residue in controlling the substrate’s orientation. Motivated by these observations, we proposed a modified intermediate in which a water molecule is strategically placed to stabilize the conserved asparagine residue. Subsequent classical MD simulations showed that the modified intermediate is able to form a reactive complex with the substrate, consistent with the experimentally observed selectivity of SCD1. A cluster model DFT study showed that the modified intermediate is of similar reactivity as the previously reported intermediate. The free energy barrier for the first hydrogen atom abstraction step by the modified intermediate was estimated to be accessible. The estimate is based on a hybrid quantum mechanics/molecular mechanics (QM/MM) approach utilizing the efficient semiempirical GFN2-xTB method. Considering its computational efficiency, GFN2-xTB seems to be a promising tool for the study of complex transition metal systems. Overall, our findings reveal important structure–function relationships in SCD1, uncovering an interplay between conserved residues and regioselectivity which advances our understanding of the entire class of transmembrane nonheme diiron enzymes.
{"title":"Understanding Substrate Binding and Reactivity of Stearoyl-CoA Desaturase (SCD1) through Classical and Multiscale Molecular Dynamics Simulations","authors":"Janko Čivić, Iñaki Tuñón, Jeremy N. Harvey","doi":"10.1021/acscatal.4c06972","DOIUrl":"https://doi.org/10.1021/acscatal.4c06972","url":null,"abstract":"Stearoyl-CoA desaturase (SCD1) plays an important role in the metabolism of fatty acids and is a promising therapeutic target. However, the underlying mechanism of SCD1, as well as other transmembrane nonheme diiron enzymes, remains poorly understood. This study builds upon a previous density functional theory (DFT) cluster model study which proposed a potential reactive intermediate of SCD1. We assessed its dynamical properties by employing classical molecular dynamics (MD) simulations. The simulations revealed that the proposed intermediate lacks the ability to form a favorable reactive complex with stearoyl-CoA, highlighting the significance of a conserved asparagine residue in controlling the substrate’s orientation. Motivated by these observations, we proposed a modified intermediate in which a water molecule is strategically placed to stabilize the conserved asparagine residue. Subsequent classical MD simulations showed that the modified intermediate is able to form a reactive complex with the substrate, consistent with the experimentally observed selectivity of SCD1. A cluster model DFT study showed that the modified intermediate is of similar reactivity as the previously reported intermediate. The free energy barrier for the first hydrogen atom abstraction step by the modified intermediate was estimated to be accessible. The estimate is based on a hybrid quantum mechanics/molecular mechanics (QM/MM) approach utilizing the efficient semiempirical GFN2-xTB method. Considering its computational efficiency, GFN2-xTB seems to be a promising tool for the study of complex transition metal systems. Overall, our findings reveal important structure–function relationships in SCD1, uncovering an interplay between conserved residues and regioselectivity which advances our understanding of the entire class of transmembrane nonheme diiron enzymes.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"39 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986063","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}
Pub Date : 2025-01-16DOI: 10.1021/acscatal.4c03189
Sriram Katipamula, Andrew W. Cook, Isabella Niedzwiecki, Chathumini Nadeesha, Ashish Parihar, Thomas J. Emge, Kate M. Waldie
We report a family of cobalt complexes based on bidentate phosphine ligands with two, one, or zero pendent amine groups in the ligand backbone. The pendent amine complexes are active electrocatalysts for the formate oxidation reaction, generating CO2 with near-quantitative faradaic efficiency at moderate overpotentials (0.45–0.57 V in acetonitrile). Thermodynamic measurements reveal that these complexes are energetically primed for formate oxidation via hydride transfer to the cobalt center, followed by deprotonation of the resulting cobalt-hydride by formate acting as a base. The complex featuring a single pendent amine arm is the fastest electrocatalyst in this series, with an observed rate constant for formate oxidation of 135 ± 8 h–1 at 25 °C, surpassing the activity of the bis-pendent amine analogue. Electrocatalytic turnover is not observed for the complex with no pendent amine groups: decomposition of the complex is evident in the presence of high formate concentrations. Thus, the application of thermodynamic considerations to electrocatalyst design is demonstrated as a successful strategy, while also highlighting the delicate balance of ligand properties necessary for achieving productive turnover.
{"title":"Electrocatalytic Formate Oxidation by Cobalt–Phosphine Complexes","authors":"Sriram Katipamula, Andrew W. Cook, Isabella Niedzwiecki, Chathumini Nadeesha, Ashish Parihar, Thomas J. Emge, Kate M. Waldie","doi":"10.1021/acscatal.4c03189","DOIUrl":"https://doi.org/10.1021/acscatal.4c03189","url":null,"abstract":"We report a family of cobalt complexes based on bidentate phosphine ligands with two, one, or zero pendent amine groups in the ligand backbone. The pendent amine complexes are active electrocatalysts for the formate oxidation reaction, generating CO<sub>2</sub> with near-quantitative faradaic efficiency at moderate overpotentials (0.45–0.57 V in acetonitrile). Thermodynamic measurements reveal that these complexes are energetically primed for formate oxidation via hydride transfer to the cobalt center, followed by deprotonation of the resulting cobalt-hydride by formate acting as a base. The complex featuring a single pendent amine arm is the fastest electrocatalyst in this series, with an observed rate constant for formate oxidation of 135 ± 8 h<sup>–1</sup> at 25 °C, surpassing the activity of the bis-pendent amine analogue. Electrocatalytic turnover is not observed for the complex with no pendent amine groups: decomposition of the complex is evident in the presence of high formate concentrations. Thus, the application of thermodynamic considerations to electrocatalyst design is demonstrated as a successful strategy, while also highlighting the delicate balance of ligand properties necessary for achieving productive turnover.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"6 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988233","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}
Pub Date : 2025-01-16DOI: 10.1021/acscatal.4c07181
Ritwika Chatterjee, Reena Balhara, Garima Jindal
Fumarase is among the most proficient enzymes and provides a 1015 fold rate enhancement in catalyzing the reversible hydration/dehydration reaction of fumarate/malate. Despite its biological significance, to date, no studies have explained the mechanism and massive catalytic efficiency that lies very close to the diffusion limit. In this report, we present a comprehensive computational study of the iron-independent class II fumarase by employing DFT calculations, MD simulations, QM cluster models, and QM/MM calculations. A carbanionic pathway is found to underlie the catalytic mechanism, both in the aqueous medium and the protein, supported by an extensive hydrogen bond network with the polar substrate at the active site of fumarase. The protein scaffold, beyond the catalytic residues and the active site, is found to have a profound electrostatic effect on amplifying the rate of this reversible reaction. The enormous catalytic efficiency is traced back to a strong electric field at the active site, which has evolved for the selective stabilization of all the higher energy intermediates and transition states along the reaction path compared to the reactant and product. Furthermore, the detrimental effect on catalytic performance upon disruption of the preorganized active site has been investigated through mutational studies. These results underscore the pivotal role of the intrinsic electric field of the enzyme in driving the near-perfect catalytic efficiency of fumarase and provide key insights into enzymatic olefin hydration reactions.
{"title":"Electrostatic Edge: Decrypting the Near-Perfect Catalytic Efficiency of Fumarase","authors":"Ritwika Chatterjee, Reena Balhara, Garima Jindal","doi":"10.1021/acscatal.4c07181","DOIUrl":"https://doi.org/10.1021/acscatal.4c07181","url":null,"abstract":"Fumarase is among the most proficient enzymes and provides a 10<sup>15</sup> fold rate enhancement in catalyzing the reversible hydration/dehydration reaction of fumarate/malate. Despite its biological significance, to date, no studies have explained the mechanism and massive catalytic efficiency that lies very close to the diffusion limit. In this report, we present a comprehensive computational study of the iron-independent class II fumarase by employing DFT calculations, MD simulations, QM cluster models, and QM/MM calculations. A carbanionic pathway is found to underlie the catalytic mechanism, both in the aqueous medium and the protein, supported by an extensive hydrogen bond network with the polar substrate at the active site of fumarase. The protein scaffold, beyond the catalytic residues and the active site, is found to have a profound electrostatic effect on amplifying the rate of this reversible reaction. The enormous catalytic efficiency is traced back to a strong electric field at the active site, which has evolved for the selective stabilization of all the higher energy intermediates and transition states along the reaction path compared to the reactant and product. Furthermore, the detrimental effect on catalytic performance upon disruption of the preorganized active site has been investigated through mutational studies. These results underscore the pivotal role of the intrinsic electric field of the enzyme in driving the near-perfect catalytic efficiency of fumarase and provide key insights into enzymatic olefin hydration reactions.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"44 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988305","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}
Efficient and selective cleavage and functionalization of C–C bonds is of critical significance in fine chemistry and lignocellulosic biomass valorization, yet it is still challenging due to their inert nature. In the present work, we report an atomically dispersed Cu catalyst encapsulated in N-doped porous carbon (Cu@NC-900) through a facile method using metal–organic frameworks (MOFs) as precursors, where Cu atoms were chelated and stabilized by N species. The resulting catalyst exhibited good performance for oxidative cleavage of C–C bonds toward esters, giving a 98.6% yield of methyl benzoate with complete conversion of acetophenone under base-free conditions. Further, the Cu@NC-900 catalyst was efficient for the conversion of a wide range of ketones, including (hetero)aryl methyl ketones or challenging alkyl ketones, to their corresponding esters. Experiments demonstrated that the highly dispersed Cu sites and incorporation of N species, as well as the rich pore structures, contributed to the high activity, selectivity, and stability. Theoretical calculations further attributed the high activity to the oxidation state formed by the electron loss of the isolated Cu atoms.
{"title":"Atomically Dispersed Cu Atoms Anchored on N-Doped Porous Carbon as an Efficient Catalyst for C–C Bond Cleavage of Ketones toward Esters","authors":"Yushan Wu, Yao Luo, Siyi Huang, Jida Wang, Junchen Xu, Xiang-Kui Gu, Mingyue Ding","doi":"10.1021/acscatal.4c06769","DOIUrl":"https://doi.org/10.1021/acscatal.4c06769","url":null,"abstract":"Efficient and selective cleavage and functionalization of C–C bonds is of critical significance in fine chemistry and lignocellulosic biomass valorization, yet it is still challenging due to their inert nature. In the present work, we report an atomically dispersed Cu catalyst encapsulated in N-doped porous carbon (Cu@NC-900) through a facile method using metal–organic frameworks (MOFs) as precursors, where Cu atoms were chelated and stabilized by N species. The resulting catalyst exhibited good performance for oxidative cleavage of C–C bonds toward esters, giving a 98.6% yield of methyl benzoate with complete conversion of acetophenone under base-free conditions. Further, the Cu@NC-900 catalyst was efficient for the conversion of a wide range of ketones, including (hetero)aryl methyl ketones or challenging alkyl ketones, to their corresponding esters. Experiments demonstrated that the highly dispersed Cu sites and incorporation of N species, as well as the rich pore structures, contributed to the high activity, selectivity, and stability. Theoretical calculations further attributed the high activity to the oxidation state formed by the electron loss of the isolated Cu atoms.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"27 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142988301","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 enantioselective three-component dicarbonfunctionalization of electronically unactivated alkenes continues to pose a significant challenge. In this work, a copper-catalyzed highly regio- and enantioselective fluoroalkylalkynylation of unactivated alkenes with diverse terminal alkynes and fluoroalkyl halides under mild conditions is developed. In addition to fluoroalkyl halides, Togni’s reagent can also participate in the reaction, delivering chiral β-trifluoromethyl alkynes with high enantioselectivities. This method exhibits good functional group tolerance, facilitating the late-stage derivatization of a variety of biologically active molecules. The success of this chemistry was achieved by using a bulky indene-substituted BOPA ligand. DFT calculations indicate that the radical fluoroalkylalkynylation is achieved through a fluorine-directed outer-sphere pathway. Mechanistic studies reveal that the amide group is crucial for achieving high stereoselectivities because the exclusive F···H hydrogen bonding between the fluoroalkyl group and the Mes group on the amide can be formed to stabilize the Si-radical coupling transition state.
{"title":"Copper-Catalyzed Enantioselective Three-Component Fluoroalkylalkynylation of Unactivated Alkenes","authors":"Mengxia Liao, Cuihuan Geng, Zhengze Wu, Chunxiang Pan, Chenwei Wang, Guanghui Meng, Xiaoyan Zuo, Ying Zhu, Xiaotian Qi, Guozhu Zhang, Rui Guo","doi":"10.1021/acscatal.4c06641","DOIUrl":"https://doi.org/10.1021/acscatal.4c06641","url":null,"abstract":"The enantioselective three-component dicarbonfunctionalization of electronically unactivated alkenes continues to pose a significant challenge. In this work, a copper-catalyzed highly regio- and enantioselective fluoroalkylalkynylation of unactivated alkenes with diverse terminal alkynes and fluoroalkyl halides under mild conditions is developed. In addition to fluoroalkyl halides, Togni’s reagent can also participate in the reaction, delivering chiral β-trifluoromethyl alkynes with high enantioselectivities. This method exhibits good functional group tolerance, facilitating the late-stage derivatization of a variety of biologically active molecules. The success of this chemistry was achieved by using a bulky indene-substituted BOPA ligand. DFT calculations indicate that the radical fluoroalkylalkynylation is achieved through a fluorine-directed outer-sphere pathway. Mechanistic studies reveal that the amide group is crucial for achieving high stereoselectivities because the exclusive F···H hydrogen bonding between the fluoroalkyl group and the Mes group on the amide can be formed to stabilize the <i>Si</i>-radical coupling transition state.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"43 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986062","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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