Pub Date : 2025-03-11DOI: 10.1021/acscatal.5c01099
Zheng Chen, Zhangyun Liu, Xin Xu
Methanol synthesis via CO2 hydrogenation on copper-based catalysts is an emerging industrial process that has a growing importance in chemical production. Yet, the elucidation of the reaction mechanisms and the identification of active sites remain subjects of ongoing debate. Due to experimental challenges, experiments alone are insufficient to provide a complete picture of the energy landscape. Meanwhile, the proposed reaction mechanisms often rely on density functional theory calculations at the generalized gradient approximation (GGA) level, which can introduce considerable uncertainty. Here, we employ an advanced hybrid method, XYG3:GGA, that combines the doubly hybrid XYG3 functional with the periodic GGA to investigate the methanol synthesis on the Cu(111) surface. This hybrid method yields results that align well with the available energy landscape in the experiment while resolving the controversy between the experimental observation of the H2COO* intermediate and the GGA-predicted pathway from the HCOOH* intermediate. It further clarifies that the Cu(111) site makes such an insignificant contribution that it cannot be considered the active site for the methanol formation on copper catalysts. These findings highlight the importance of using more accurate methods, such as XYG3:GGA, to elucidate the reaction mechanism and identify the active site, thereby bridging the gap between the experiment and theory.
{"title":"Clarifying the Methanol Synthesis Mechanism via CO2 Hydrogenation on the Cu(111) Surface: Insights from Accurate Doubly Hybrid Density Functionals","authors":"Zheng Chen, Zhangyun Liu, Xin Xu","doi":"10.1021/acscatal.5c01099","DOIUrl":"https://doi.org/10.1021/acscatal.5c01099","url":null,"abstract":"Methanol synthesis via CO<sub>2</sub> hydrogenation on copper-based catalysts is an emerging industrial process that has a growing importance in chemical production. Yet, the elucidation of the reaction mechanisms and the identification of active sites remain subjects of ongoing debate. Due to experimental challenges, experiments alone are insufficient to provide a complete picture of the energy landscape. Meanwhile, the proposed reaction mechanisms often rely on density functional theory calculations at the generalized gradient approximation (GGA) level, which can introduce considerable uncertainty. Here, we employ an advanced hybrid method, XYG3:GGA, that combines the doubly hybrid XYG3 functional with the periodic GGA to investigate the methanol synthesis on the Cu(111) surface. This hybrid method yields results that align well with the available energy landscape in the experiment while resolving the controversy between the experimental observation of the H<sub>2</sub>COO* intermediate and the GGA-predicted pathway from the HCOOH* intermediate. It further clarifies that the Cu(111) site makes such an insignificant contribution that it cannot be considered the active site for the methanol formation on copper catalysts. These findings highlight the importance of using more accurate methods, such as XYG3:GGA, to elucidate the reaction mechanism and identify the active site, thereby bridging the gap between the experiment and theory.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"52 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143589646","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 : 2025-03-11DOI: 10.1021/acscatal.5c00668
Jia-qi Bai, Mei Ma, Huangfei Liu, Zhangkai Qian, Durui Liu, Yuncai Zhao, Yijing Gao, Jingshuai Chen, Mengdie Cai, Song Sun
The hydrogenation of nitriles is an environmentally friendly and atom-economical route to prepare high-value amines; however, it is still a challenge to control selectivity because of the occurrence of hydrogenation, self-coupling, and hydrogenolysis reactions during the hydrogenation process. It is highly desirable to develop efficient non-noble-metal catalysts for the hydrogenation of nitriles to secondary amines, although several noble metal catalysts have been reported. Herein, we successfully prepared a Cu–Ni/W20O58 catalyst and found that the Cu4.4–Ni0.6/W20O58 catalyst showed a 92.3% yield with initial TOFs of 270.0 h–1 at 373 K and 3 MPa H2 for the hydrogenation of benzonitrile (BN) to dibenzylamine (DBA), which was much superior to that of the monometallic Cu4.4/W20O58 and Ni0.6/W20O58 catalysts. Moreover, the Cu4.4–Ni0.6/W20O58 catalyst could be reused at least 4 times and was effective for the hydrogenation of various nitriles with superior selectivity to secondary amines. Furthermore, the reaction mechanism of BN hydrogenation for the Cu–Ni alloy of Cu4.4–Ni0.6/W20O58 was proposed on the basis of spectroscopic studies such as XRD, TPR, TEM, XAFS, and XPS, kinetic studies such as the effect of BN concentration and H2 pressure, the isotopic effect of hydrogen, and the effect of the reaction temperature and DFT calculations. The rate-determining step was the hydrogenation of benzylidenamine (BI) to the half-hydrogenated intermediate by one H atom over the Cu4.4–Ni0.6/W20O58 catalyst. The Ni–W20O58 interface was responsible for the adsorption and activation of BN, and the electron-rich Cu acted as the site for H2 dissociation; the synergistic effect of Cu and Ni led to the superior catalytic performance of the Cu4.4–Ni0.6/W20O58 catalyst.
{"title":"Efficient Cu–Ni/W20O58 Catalysts for Hydrogenation of Nitriles to Secondary Amines","authors":"Jia-qi Bai, Mei Ma, Huangfei Liu, Zhangkai Qian, Durui Liu, Yuncai Zhao, Yijing Gao, Jingshuai Chen, Mengdie Cai, Song Sun","doi":"10.1021/acscatal.5c00668","DOIUrl":"https://doi.org/10.1021/acscatal.5c00668","url":null,"abstract":"The hydrogenation of nitriles is an environmentally friendly and atom-economical route to prepare high-value amines; however, it is still a challenge to control selectivity because of the occurrence of hydrogenation, self-coupling, and hydrogenolysis reactions during the hydrogenation process. It is highly desirable to develop efficient non-noble-metal catalysts for the hydrogenation of nitriles to secondary amines, although several noble metal catalysts have been reported. Herein, we successfully prepared a Cu–Ni/W<sub>20</sub>O<sub>58</sub> catalyst and found that the Cu<sub>4.4</sub>–Ni<sub>0.6</sub>/W<sub>20</sub>O<sub>58</sub> catalyst showed a 92.3% yield with initial TOF<sub>s</sub> of 270.0 h<sup>–1</sup> at 373 K and 3 MPa H<sub>2</sub> for the hydrogenation of benzonitrile (BN) to dibenzylamine (DBA), which was much superior to that of the monometallic Cu<sub>4.4</sub>/W<sub>20</sub>O<sub>58</sub> and Ni<sub>0.6</sub>/W<sub>20</sub>O<sub>58</sub> catalysts. Moreover, the Cu<sub>4.4</sub>–Ni<sub>0.6</sub>/W<sub>20</sub>O<sub>58</sub> catalyst could be reused at least 4 times and was effective for the hydrogenation of various nitriles with superior selectivity to secondary amines. Furthermore, the reaction mechanism of BN hydrogenation for the Cu–Ni alloy of Cu<sub>4.4</sub>–Ni<sub>0.6</sub>/W<sub>20</sub>O<sub>58</sub> was proposed on the basis of spectroscopic studies such as XRD, TPR, TEM, XAFS, and XPS, kinetic studies such as the effect of BN concentration and H<sub>2</sub> pressure, the isotopic effect of hydrogen, and the effect of the reaction temperature and DFT calculations. The rate-determining step was the hydrogenation of benzylidenamine (BI) to the half-hydrogenated intermediate by one H atom over the Cu<sub>4.4</sub>–Ni<sub>0.6</sub>/W<sub>20</sub>O<sub>58</sub> catalyst. The Ni–W<sub>20</sub>O<sub>58</sub> interface was responsible for the adsorption and activation of BN, and the electron-rich Cu acted as the site for H<sub>2</sub> dissociation; the synergistic effect of Cu and Ni led to the superior catalytic performance of the Cu<sub>4.4</sub>–Ni<sub>0.6</sub>/W<sub>20</sub>O<sub>58</sub> catalyst.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"596 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599625","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 catalytic upgrading of ethanol to 1,3-butadiene (1,3-BD) (ETB) plays a pivotal role in developing renewable industrial technologies. This process has the promising potential to replace the 1,3-BD traditional production technology, which relies on fossil energy, such as naphtha cracking byproducts for ethylene production. The utilization of metal–zeolite catalysts has significantly enhanced catalytic performance; however, a comprehensive review of the progress made in this field is still lacking. In this review, we summarize recent advancements in catalytic performance achieved by employing various metal components supported on silicon-based catalysts through diverse design strategies. Furthermore, the structure–activity relationships of the catalysts, identification of active sites, and the corresponding reaction mechanisms are comprehensively demonstrated. Finally, we discuss the current challenges and future research avenues for designing high-performance catalysts to improve the prospects for the industrial application of ETB.
{"title":"Recent Advances in Metal–Zeolite Catalysts for Ethanol to 1,3-Butadiene Conversion: Active Metal Sites, Mechanisms, and Future Challenges","authors":"Xianquan Li, Yujia Zhao, Jifeng Pang, Pan Gao, Mingyuan Zheng, Guangjin Hou","doi":"10.1021/acscatal.5c00888","DOIUrl":"https://doi.org/10.1021/acscatal.5c00888","url":null,"abstract":"The catalytic upgrading of ethanol to 1,3-butadiene (1,3-BD) (ETB) plays a pivotal role in developing renewable industrial technologies. This process has the promising potential to replace the 1,3-BD traditional production technology, which relies on fossil energy, such as naphtha cracking byproducts for ethylene production. The utilization of metal–zeolite catalysts has significantly enhanced catalytic performance; however, a comprehensive review of the progress made in this field is still lacking. In this review, we summarize recent advancements in catalytic performance achieved by employing various metal components supported on silicon-based catalysts through diverse design strategies. Furthermore, the structure–activity relationships of the catalysts, identification of active sites, and the corresponding reaction mechanisms are comprehensively demonstrated. Finally, we discuss the current challenges and future research avenues for designing high-performance catalysts to improve the prospects for the industrial application of ETB.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"54 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599600","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 : 2025-03-11DOI: 10.1021/acscatal.4c07899
Tao Dong, Xuanning Wu, Fei Xiao, Jian Ji, Pingli Huang, Haibao Huang
In heterogeneous catalysis, the presence of H2O often has complex effects on the catalyst performance. It can both cause active site poisoning and play a positive role in certain reactions, such as HCHO and CO oxidation. However, H2O activation and humidity adaptability remain significant challenges in low-temperature catalytic oxidation reactions. Herein, an ultraefficient Pd–Ox–K active site located within the silicalite-1 (S-1) zeolite (marked as Kx–Pd@S-1) was successfully constructed through an in situ encapsulation and alkali metal modification strategy. Kx–Pd@S-1 exhibits satisfactory low-temperature oxidation activity and durability in HCHO and CO removal. Experiments demonstrate that the addition of the alkali metal K significantly accelerates H2O activation, generating abundant surface hydroxyl (−OH) species. Even under high-humidity (RH = 90%) conditions, K0.5–Pd@S-1 exhibits remarkable H2O resistance. Cycling tests reveal that K0.5–Pd@S-1 has considerable repeatability and stability, with the HCHO conversion remaining at 98% even after 5 testing cycles. The enhanced activity is attributed to Pd–Ox–K sites, providing efficient adsorption and activation sites for reactants. Moreover, the reaction mechanism study confirms that reactive oxygen species (O2–, O22–, and −OH) coaccelerate the degradation of key intermediate species. This work provides valuable insights into the design of efficient catalysts for practical applications.
{"title":"Enhanced Water Activation via Alkali Metal-Modified Pd Clusters: A Key to Boosting HCHO and CO Oxidation","authors":"Tao Dong, Xuanning Wu, Fei Xiao, Jian Ji, Pingli Huang, Haibao Huang","doi":"10.1021/acscatal.4c07899","DOIUrl":"https://doi.org/10.1021/acscatal.4c07899","url":null,"abstract":"In heterogeneous catalysis, the presence of H<sub>2</sub>O often has complex effects on the catalyst performance. It can both cause active site poisoning and play a positive role in certain reactions, such as HCHO and CO oxidation. However, H<sub>2</sub>O activation and humidity adaptability remain significant challenges in low-temperature catalytic oxidation reactions. Herein, an ultraefficient Pd–O<sub><i>x</i></sub>–K active site located within the silicalite-1 (S-1) zeolite (marked as K<sub><i>x</i></sub>–Pd@S-1) was successfully constructed through an in situ encapsulation and alkali metal modification strategy. K<sub><i>x</i></sub>–Pd@S-1 exhibits satisfactory low-temperature oxidation activity and durability in HCHO and CO removal. Experiments demonstrate that the addition of the alkali metal K significantly accelerates H<sub>2</sub>O activation, generating abundant surface hydroxyl (−OH) species. Even under high-humidity (RH = 90%) conditions, K<sub>0.5</sub>–Pd@S-1 exhibits remarkable H<sub>2</sub>O resistance. Cycling tests reveal that K<sub>0.5</sub>–Pd@S-1 has considerable repeatability and stability, with the HCHO conversion remaining at 98% even after 5 testing cycles. The enhanced activity is attributed to Pd–O<sub><i>x</i></sub>–K sites, providing efficient adsorption and activation sites for reactants. Moreover, the reaction mechanism study confirms that reactive oxygen species (O<sub>2</sub><sup>–</sup>, O<sub>2</sub><sup>2–</sup>, and −OH) coaccelerate the degradation of key intermediate species. This work provides valuable insights into the design of efficient catalysts for practical applications.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"12 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599599","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 : 2025-03-11DOI: 10.1021/acscatal.5c01208
Courtney M. Sever, Alec M. Esper, Ion Ghiviriga, Daniel W. Lester, Arkadios Marathianos, Christian Ehm, Adam S. Veige
We report the one-step synthesis of a double-tethered metallacyclobutane molybdenum catalyst for ring expansion metathesis polymerization, a method increasingly popular for cyclic polymer production. The metallacyclobutane’s geometry, based on 13C NMR and DFT analysis, suggests it should not participate in metathesis. However, polymerization of norbornene showed high activity (an upper limit of 1,000,000,000 gpolymer molcat–1 h–1). DFT studies reveal that the catalyst’s slow initiation and fast propagation arise from a self-accelerating effect triggered by increasing steric demand, causing a geometry shift from square-pyramidal to trigonal bipyramidal. This insight will advance catalyst design principles and, in the future, allow for more precise control of the molecular weight, dispersity, and tacticity.
{"title":"Self-Accelerating Ring Expansion Metathesis Polymerization","authors":"Courtney M. Sever, Alec M. Esper, Ion Ghiviriga, Daniel W. Lester, Arkadios Marathianos, Christian Ehm, Adam S. Veige","doi":"10.1021/acscatal.5c01208","DOIUrl":"https://doi.org/10.1021/acscatal.5c01208","url":null,"abstract":"We report the one-step synthesis of a double-tethered metallacyclobutane molybdenum catalyst for ring expansion metathesis polymerization, a method increasingly popular for cyclic polymer production. The metallacyclobutane’s geometry, based on <sup>13</sup>C NMR and DFT analysis, suggests it should not participate in metathesis. However, polymerization of norbornene showed high activity (an upper limit of 1,000,000,000 g<sub>polymer</sub> mol<sub>cat</sub><sup>–1</sup> h<sup>–1</sup>). DFT studies reveal that the catalyst’s slow initiation and fast propagation arise from a self-accelerating effect triggered by increasing steric demand, causing a geometry shift from square-pyramidal to trigonal bipyramidal. This insight will advance catalyst design principles and, in the future, allow for more precise control of the molecular weight, dispersity, and tacticity.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"5 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143590167","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 : 2025-03-10DOI: 10.1021/acscatal.5c01167
Chang Cai, Yuzhou Huang, Lin Zhang, Liang Zhang
β-Ketoacyl-ACP synthases (KAS) catalyze carbon skeleton extension in numerous metabolic routes such as the fatty acid biosynthesis pathway (FAS), among which FabH is the only known member that links the initiation stage to the elongation cycle of type-II FAS (FAS-II) by catalyzing condensation between acetyl-CoA and malonyl-ACP for the first β-keto-ACP intermediate acetoacetyl-ACP formation. Here, we reveal the substrate selection and condensation mechanisms of FabH from Escherichia coli. We demonstrate that EcFabH binds CoA and ACP using distinct regions in an irreversible compulsory order. The malonyl moiety is then delivered to a hydrophobic cage near the catalytic triad residues through front and middle door residues in the tunnel, and the substrate length is selected by a backdoor residue Phe87, ensuring the preferential recognition of EcFabH on acetyl moiety carried by CoA rather than longer substrates. Moreover, the malonyl moiety is locked in the cage by the acetylated Cys112 from the transacylation reaction, triggering the subsequent decarboxylation and condensation catalysis. Our study provides fundamental mechanistic insights into the initial extension of carbon skeletons catalyzed by FabH and homologues in FAS, PKS, and biotin biosynthesis pathways and may facilitate protein engineering and optimization for synthetic biological and pharmaceutical industry, as well as antibacterial drug development.
{"title":"The Molecular Basis of the β-Ketoacyl-ACP Synthase FabH in Catalyzing C–C Bond Formation of Acetoacetyl-ACP","authors":"Chang Cai, Yuzhou Huang, Lin Zhang, Liang Zhang","doi":"10.1021/acscatal.5c01167","DOIUrl":"https://doi.org/10.1021/acscatal.5c01167","url":null,"abstract":"β-Ketoacyl-ACP synthases (KAS) catalyze carbon skeleton extension in numerous metabolic routes such as the fatty acid biosynthesis pathway (FAS), among which FabH is the only known member that links the initiation stage to the elongation cycle of type-II FAS (FAS-II) by catalyzing condensation between acetyl-CoA and malonyl-ACP for the first β-keto-ACP intermediate acetoacetyl-ACP formation. Here, we reveal the substrate selection and condensation mechanisms of FabH from <i>Escherichia coli</i>. We demonstrate that <i>Ec</i>FabH binds CoA and ACP using distinct regions in an irreversible compulsory order. The malonyl moiety is then delivered to a hydrophobic cage near the catalytic triad residues through front and middle door residues in the tunnel, and the substrate length is selected by a backdoor residue Phe87, ensuring the preferential recognition of <i>Ec</i>FabH on acetyl moiety carried by CoA rather than longer substrates. Moreover, the malonyl moiety is locked in the cage by the acetylated Cys112 from the transacylation reaction, triggering the subsequent decarboxylation and condensation catalysis. Our study provides fundamental mechanistic insights into the initial extension of carbon skeletons catalyzed by FabH and homologues in FAS, PKS, and biotin biosynthesis pathways and may facilitate protein engineering and optimization for synthetic biological and pharmaceutical industry, as well as antibacterial drug development.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"19 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143589874","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 ZnO surface is easily reduced during alkane dehydrogenation owing to the formation of surface hydrogen species, resulting in poor catalytic performance. Aiming at revealing ZnO surface structure evolution, the degree of surface reduction, catalyst stability, and the type of key species contributing to surface reduction in the ethane dehydrogenation (EDH) reaction, this work fully investigated the mechanism of the EDH reaction over ZnO and a series of ZnO-based catalysts by using DFT calculations and kMC simulations. The results show that ZnO surface reduction is mainly caused by the interaction of surface H* species from EDH with surface lattice oxygen to generate H2O(g), leading to surface oxygen vacancy (Ov) formation over ZnO. As the EDH reaction proceeds, the number of Ov increases, and the active center gradually shifts from the Zn–O site to the Zn–Zncus site, decreasing the C2H4(g) formation activity and ultimately deactivating the ZnO catalyst. Furthermore, the second metal M is introduced into the ZnO surface to construct M/ZnO catalysts, and the Mn/ZnO catalyst is screened out to present better catalytic performance, which is not easily reduced. This work is of great significance in laying a solid foundation for optimizing the catalytic performance of the EDH reaction over ZnO-based catalysts.
{"title":"Unraveling the Roles of the ZnO Surface Structure and Second Metal Doping in Tuning the Catalytic Performance of Ethane Dehydrogenation","authors":"Lixing Zhang, Bingying Han, Baojun Wang, Maohong Fan, Lixia Ling, Riguang Zhang","doi":"10.1021/acscatal.4c08002","DOIUrl":"https://doi.org/10.1021/acscatal.4c08002","url":null,"abstract":"The ZnO surface is easily reduced during alkane dehydrogenation owing to the formation of surface hydrogen species, resulting in poor catalytic performance. Aiming at revealing ZnO surface structure evolution, the degree of surface reduction, catalyst stability, and the type of key species contributing to surface reduction in the ethane dehydrogenation (EDH) reaction, this work fully investigated the mechanism of the EDH reaction over ZnO and a series of ZnO-based catalysts by using DFT calculations and kMC simulations. The results show that ZnO surface reduction is mainly caused by the interaction of surface H* species from EDH with surface lattice oxygen to generate H<sub>2</sub>O(g), leading to surface oxygen vacancy (O<sub>v</sub>) formation over ZnO. As the EDH reaction proceeds, the number of O<sub>v</sub> increases, and the active center gradually shifts from the Zn–O site to the Zn–Zn<sub>cus</sub> site, decreasing the C<sub>2</sub>H<sub>4</sub>(g) formation activity and ultimately deactivating the ZnO catalyst. Furthermore, the second metal M is introduced into the ZnO surface to construct M/ZnO catalysts, and the Mn/ZnO catalyst is screened out to present better catalytic performance, which is not easily reduced. This work is of great significance in laying a solid foundation for optimizing the catalytic performance of the EDH reaction over ZnO-based catalysts.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"40 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143589873","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 : 2025-03-10DOI: 10.1021/acscatal.4c07204
Katherine O. Puffer, Brandon S. Portela, Alexis J. Olson-Gwin, Katherine A. Chism, Sylwia Dworakowska, Ethan J. Crace, Robert S. Paton, Garret M. Miyake
The development of N,N-diaryl dihydrophenazine organic photoredox catalysts (PCs) has enabled numerous examples of organocatalyzed atom transfer radical polymerization (O-ATRP) of methyl methacrylate (MMA) monomer to polymers with low dispersity (Đ < 1.30) and near-unity initiator efficiency (I* ∼ 100%), as well as small molecule synthesis. In this work, we investigate the influence of core substitution (CS) by alkyl, aryl, and heteroatom groups on singlet excited state reduction potential (ES1°*). We observe that a highly reducing ES1°* is in part a result of a locally excited (LE)-dominated hybridized local and charge transfer (HLCT) excited state in CS PCs, which is influenced by the identity of the core substituent. Additionally, the PCs that possess a LE-dominated HLCT character maintain a relatively oxidizing PC radical cation oxidation potential (E1/2) for deactivation in O-ATRP compared to fully LE PCs reported in prior work. For example, a thiophenol core substituted (heteroatom CS, HetCS) PC shows the most negative ES1°* (−2.07 V vs SCE), more LE character (Stokes shift = 124 nm), and has an oxidizing PC radical cation (E1/2 = 0.30 V vs SCE). The CS PCs with improved properties, including more negative ES1°*, perform best in O-ATRP of MMA with the HetCS PC showing the best control in both DMAc (Đ = 1.08, I* = 89%) and EtOAc (Đ = 1.06, I* = 97%). Additionally, the HetCS PC was found to mediate the controlled polymerization of n-butyl acrylate (n-BA) (Đ = 1.24, I* = 97%), which has remained challenging in O-ATRP without supplemental deactivation strategies. An aryl CS PC was found to have moderate control as low as 1 ppm PC, indicating facilitation of low PC loadings (Đ = 1.33, I* = 69%). The relationship between excited state character, ES1°*, and polymerization control observed in this work provides a foundation for increasing the utility of phenazine PCs across photoredox catalysis.
随着 N,N-二芳基二氢吩嗪有机光氧化催化剂（PCs）的开发，甲基丙烯酸甲酯（MMA）单体的有机催化原子转移自由基聚合（O-ATPR）成为具有低分散性（Đ < 1.30）和接近统一引发剂效率（I* ∼ 100%）的聚合物以及小分子合成的大量实例。在这项工作中，我们研究了烷基、芳基和杂原子基团的核取代（CS）对单线激发态还原电位（ES1°*）的影响。我们观察到，高还原 ES1°* 部分是 CS PC 中以局部激发（LE）为主的杂化局部和电荷转移（HLCT）激发态的结果，而这种激发态受到核心取代基身份的影响。此外，与之前研究中报道的完全 LE PC 相比，具有 LE 主导 HLCT 特性的 PC 在 O-ATRP 中保持了相对氧化的 PC 自由基阳离子氧化电位（E1/2）。例如，噻吩酚核取代（杂原子 CS，HetCS）PC 显示出最负的 ES1°*（-2.07 V vs SCE）、更多的 LE 特性（斯托克斯偏移 = 124 nm），并具有氧化性 PC 自由基阳离子（E1/2 = 0.30 V vs SCE）。CS PC 的性能得到了改善，包括 ES1°* 更负，在 MMA 的 O-ATRP 中表现最佳，其中 HetCS PC 在 DMAc（Đ = 1.08，I* = 89%）和 EtOAc（Đ = 1.06，I* = 97%）中的控制效果最好。此外，研究还发现 HetCS PC 能够介导丙烯酸正丁酯（n-BA）的受控聚合（Đ = 1.24，I* = 97%），而在没有辅助失活策略的情况下，这种聚合在 O-ATRP 中仍然具有挑战性。研究发现，芳基 CS 多氯联苯在百万分之 1 的多氯联苯浓度下具有适度的控制能力，这表明低多氯联苯负载具有促进作用（Đ = 1.33，I* = 69%）。这项研究观察到的激发态特性、ES1°* 和聚合控制之间的关系为提高吩嗪多氯联苯在光氧化催化中的效用奠定了基础。
{"title":"Influence of Dihydrophenazine Photoredox Catalyst Excited State Character and Reduction Potentials on Control in Organocatalyzed Atom Transfer Radical Polymerization","authors":"Katherine O. Puffer, Brandon S. Portela, Alexis J. Olson-Gwin, Katherine A. Chism, Sylwia Dworakowska, Ethan J. Crace, Robert S. Paton, Garret M. Miyake","doi":"10.1021/acscatal.4c07204","DOIUrl":"https://doi.org/10.1021/acscatal.4c07204","url":null,"abstract":"The development of <i>N</i>,<i>N</i>-diaryl dihydrophenazine organic photoredox catalysts (PCs) has enabled numerous examples of organocatalyzed atom transfer radical polymerization (O-ATRP) of methyl methacrylate (MMA) monomer to polymers with low dispersity (<i>Đ</i> < 1.30) and near-unity initiator efficiency (<i>I</i>* ∼ 100%), as well as small molecule synthesis. In this work, we investigate the influence of core substitution (CS) by alkyl, aryl, and heteroatom groups on singlet excited state reduction potential (<i>E</i><sub>S1</sub>°*). We observe that a highly reducing <i>E</i><sub>S1</sub>°* is in part a result of a locally excited (LE)-dominated hybridized local and charge transfer (HLCT) excited state in CS PCs, which is influenced by the identity of the core substituent. Additionally, the PCs that possess a LE-dominated HLCT character maintain a relatively oxidizing PC radical cation oxidation potential (<i>E</i><sub>1/2</sub>) for deactivation in O-ATRP compared to fully LE PCs reported in prior work. For example, a thiophenol core substituted (heteroatom CS, HetCS) PC shows the most negative <i>E</i><sub>S1</sub>°* (−2.07 V vs SCE), more LE character (Stokes shift = 124 nm), and has an oxidizing PC radical cation (<i>E</i><sub>1/2</sub> = 0.30 V vs SCE). The CS PCs with improved properties, including more negative <i>E</i><sub>S1</sub>°*, perform best in O-ATRP of MMA with the HetCS PC showing the best control in both DMAc (<i>Đ</i> = 1.08, <i>I*</i> = 89%) and EtOAc (<i>Đ</i> = 1.06, <i>I*</i> = 97%). Additionally, the HetCS PC was found to mediate the controlled polymerization of <i>n</i>-butyl acrylate (<i>n</i>-BA) (<i>Đ</i> = 1.24, <i>I*</i> = 97%), which has remained challenging in O-ATRP without supplemental deactivation strategies. An aryl CS PC was found to have moderate control as low as 1 ppm PC, indicating facilitation of low PC loadings (<i>Đ</i> = 1.33, <i>I*</i> = 69%). The relationship between excited state character, <i>E</i><sub>S1</sub>°*, and polymerization control observed in this work provides a foundation for increasing the utility of phenazine PCs across photoredox catalysis.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"19 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143583062","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 : 2025-03-10DOI: 10.1021/acscatal.5c00764
Taichi Yumura, Takeshi Nanjo, Yoshiji Takemoto
The radical-mediated [3 + 2] cycloaddition between α-carboxy radicals and olefins is an efficient method for the synthesis of γ-lactones. Here, we report a [3 + 2]-type lactonization via the reductive single-electron transfer (SET) and subsequent protonation of α,β-unsaturated carboxylic acids (UCAs), which are ideal α-carboxy radical precursors in terms of atom economy. The cooperative catalysis of benzophenothiazine and boronic acid efficiently promotes the formation of α-carboxy radicals from UCAs in the presence of appropriate Brønsted acids such as benzoic acid, leading to a practical synthetic method without the need for strong acids or reductants. The chemoselective activation of UCAs provides access to a wide range of alkenes, including α,β-unsaturated amides, to be used as radical acceptors. Mechanistic studies revealed that the thermodynamic stability of the α-carboxy radicals and the charge distribution of the radical anion intermediates have a significant impact on the reaction rate and regioselectivity of the protonation.
{"title":"Benzophenothiazine/Boronic Acid Cooperative Photocatalysis Enables the Synthesis of γ-Lactones via the [3 + 2] Cycloaddition of α,β-Unsaturated Carboxylic Acids with Olefins","authors":"Taichi Yumura, Takeshi Nanjo, Yoshiji Takemoto","doi":"10.1021/acscatal.5c00764","DOIUrl":"https://doi.org/10.1021/acscatal.5c00764","url":null,"abstract":"The radical-mediated [3 + 2] cycloaddition between α-carboxy radicals and olefins is an efficient method for the synthesis of γ-lactones. Here, we report a [3 + 2]-type lactonization via the reductive single-electron transfer (SET) and subsequent protonation of α,β-unsaturated carboxylic acids (UCAs), which are ideal α-carboxy radical precursors in terms of atom economy. The cooperative catalysis of benzophenothiazine and boronic acid efficiently promotes the formation of α-carboxy radicals from UCAs in the presence of appropriate Brønsted acids such as benzoic acid, leading to a practical synthetic method without the need for strong acids or reductants. The chemoselective activation of UCAs provides access to a wide range of alkenes, including α,β-unsaturated amides, to be used as radical acceptors. Mechanistic studies revealed that the thermodynamic stability of the α-carboxy radicals and the charge distribution of the radical anion intermediates have a significant impact on the reaction rate and regioselectivity of the protonation.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"68 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143583067","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 : 2025-03-10DOI: 10.1021/acscatal.4c07696
Andrey P. Kroitor, Alexander A. Dmitrienko, Gayane A. Kirakosyan, Chantal Lorentz, Alexander G. Martynov, Yulia G. Gorbunova, Aslan Yu. Tsivadze, Alexander B. Sorokin
Unprecedented chiral ruthenium(II) complexes with phthalocyanines having chiral motifs near the catalytic metal site have been prepared by cross condensation of the chiral 3,6-bis-aryloxy-phthalonitrile (α-Ar*O)2Pn bearing two (1R,2S,5R)-menthoxy groups orthogonal to the aromatic plane and (15-crown-5)phthalonitrile. Four complexes containing chiral menthyl groups (M) and 15-crown-5 units (C), notably RuPc[MC3](CO), RuPc[opp-M2C2](CO), RuPc[adj-M2C2](CO), and RuPc[M3C](CO), were isolated in pure form and fully characterized by UV–vis, circular dichroism, HRMS, and various 1H NMR and 13C NMR techniques. Their evaluation in the benchmark asymmetric cyclopropanation reaction of styrene derivatives by ethyl diazoacetate indicated that the RuPc[opp-M2C2](CO) complex was the most efficient in terms of diastereo- and enantioselectivity. Further study revealed the strong dependence of the stereoselectivity on the solvent nature and salt additives, which caused conformational rearrangement of the flexible chiral surrounding, as evidenced by multinuclear NMR and CD spectra. For instance, upon moving from commonly used CH2Cl2 to EtOH with the addition of NaPF6, a significant enhancement of enantioselectivity (from 35 to 84% with p-methylstyrene) was obtained. Of particular importance is a very high diastereoselectivity of cyclopropanation of many substrates promoted by the incorporation of sodium cations into crown ether cavities of phthalocyanine to attain a trans/cis ratio up to 499:1. Such a regulating effect in chiral catalysis involving tetrapyrrolic complexes has not been previously observed, rendering this complex a prominent example of the phthalocyanine tunable catalyst. The developed synthetic strategy paves the way to phthalocyanine complexes with a chiral environment around the metal site and crown ether receptors to tune the catalytic properties.
{"title":"Designing Ruthenium Phthalocyanine with Chiral Pockets Formed by (1R,2S,5R)-Menthoxy Groups for Enantioselective Catalysis","authors":"Andrey P. Kroitor, Alexander A. Dmitrienko, Gayane A. Kirakosyan, Chantal Lorentz, Alexander G. Martynov, Yulia G. Gorbunova, Aslan Yu. Tsivadze, Alexander B. Sorokin","doi":"10.1021/acscatal.4c07696","DOIUrl":"https://doi.org/10.1021/acscatal.4c07696","url":null,"abstract":"Unprecedented chiral ruthenium(II) complexes with phthalocyanines having chiral motifs near the catalytic metal site have been prepared by cross condensation of the chiral 3,6-bis-aryloxy-phthalonitrile (<b>α-Ar*O</b>)<sub>2</sub><b>Pn</b> bearing two (1<i>R</i>,2<i>S</i>,5<i>R</i>)-menthoxy groups orthogonal to the aromatic plane and (15-crown-5)phthalonitrile. Four complexes containing chiral menthyl groups (<b>M</b>) and 15-crown-5 units (<b>C</b>), notably <b>RuPc[MC</b><sub><b>3</b></sub><b>](CO)</b>, <b>RuPc[</b><i>opp</i><b>-M</b><sub><b>2</b></sub><b>C</b><sub><b>2</b></sub><b>](CO)</b>, <b>RuPc[</b><i>adj</i><b>-M</b><sub><b>2</b></sub><b>C</b><sub><b>2</b></sub><b>](CO)</b>, and <b>RuPc[M</b><sub><b>3</b></sub><b>C](CO)</b>, were isolated in pure form and fully characterized by UV–vis, circular dichroism, HRMS, and various <sup>1</sup>H NMR and <sup>13</sup>C NMR techniques. Their evaluation in the benchmark asymmetric cyclopropanation reaction of styrene derivatives by ethyl diazoacetate indicated that the <b>RuPc[</b><i>opp</i><b>-M</b><sub><b>2</b></sub><b>C</b><sub><b>2</b></sub><b>](CO)</b> complex was the most efficient in terms of diastereo- and enantioselectivity. Further study revealed the strong dependence of the stereoselectivity on the solvent nature and salt additives, which caused conformational rearrangement of the flexible chiral surrounding, as evidenced by multinuclear NMR and CD spectra. For instance, upon moving from commonly used CH<sub>2</sub>Cl<sub>2</sub> to EtOH with the addition of NaPF<sub>6</sub>, a significant enhancement of enantioselectivity (from 35 to 84% with <i>p</i>-methylstyrene) was obtained. Of particular importance is a very high diastereoselectivity of cyclopropanation of many substrates promoted by the incorporation of sodium cations into crown ether cavities of phthalocyanine to attain a <i>trans</i>/<i>cis</i> ratio up to 499:1. Such a regulating effect in chiral catalysis involving tetrapyrrolic complexes has not been previously observed, rendering this complex a prominent example of the phthalocyanine tunable catalyst. The developed synthetic strategy paves the way to phthalocyanine complexes with a chiral environment around the metal site and crown ether receptors to tune the catalytic properties.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"18 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143583066","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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