Pub Date : 2026-02-03DOI: 10.1021/acscatal.5c07891
Beatriz Quevedo-Flores, Mario Martinez-Lopez, Loris Laze, Manuel A. Ortuño, Irene Bosque, Jose C. Gonzalez-Gomez
The selective formation of benzyl radicals through the homogeneous photooxidation of toluene derivatives, followed by deprotonation, is difficult to implement when the involved chemical species have low oxidation potentials. Here, we present a successful application of this approach for the modular construction of biologically important 1,2-diarylethylamines from toluene derivatives, aldehydes, and anilines. This three-component reaction is driven by acridine photocatalysis under visible light, with trifluoroacetic acid (TFA) (or p-TsOH) serving as an acid additive that plays a triple role. The method is reliable, easy to use, metal-free, compatible with a wide range of functional groups, and more efficient under flow conditions. Unlike previous methods, no cocatalysts are required for the turnover of the acridine photocatalyst.
{"title":"Visible-Light-Driven Benzylation of In Situ-Formed Imines Using Toluenes and Acridine Photocatalysis","authors":"Beatriz Quevedo-Flores, Mario Martinez-Lopez, Loris Laze, Manuel A. Ortuño, Irene Bosque, Jose C. Gonzalez-Gomez","doi":"10.1021/acscatal.5c07891","DOIUrl":"https://doi.org/10.1021/acscatal.5c07891","url":null,"abstract":"The selective formation of benzyl radicals through the homogeneous photooxidation of toluene derivatives, followed by deprotonation, is difficult to implement when the involved chemical species have low oxidation potentials. Here, we present a successful application of this approach for the modular construction of biologically important 1,2-diarylethylamines from toluene derivatives, aldehydes, and anilines. This three-component reaction is driven by acridine photocatalysis under visible light, with trifluoroacetic acid (TFA) (or <i>p</i>-TsOH) serving as an acid additive that plays a triple role. The method is reliable, easy to use, metal-free, compatible with a wide range of functional groups, and more efficient under flow conditions. Unlike previous methods, no cocatalysts are required for the turnover of the acridine photocatalyst.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"1 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111005","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 : 2026-02-03DOI: 10.1021/acscatal.5c08156
David Sánchez Roa, Robert E. Mulvey, Eva Hevia
Alkali-metal compounds, particularly organolithium and lithium amide reagents, are indispensable organometallic reagents in synthesis, finding widespread applications in cornerstone stoichiometric organic processes. Recent advances in the development of heavier alkali-metal analogues have revealed their emerging potential not only to participate in stoichiometric processes but also to catalyze transformations traditionally dominated by precious transition metals. This perspective provides an overview of a selection of these applications focusing on hydrogen isotope exchange, alkene isomerization, C–C bond formation, hydrophosphination, and hydrogenation. Special focus is placed on current mechanistic understanding and alkali-metal effects, aiming to draw out key challenges and opportunities that may guide the future development of alkali-metal-mediated catalysis.
{"title":"Alkali-Metal Heavyweights: Up and Coming Contenders in Homogeneous Catalysis?","authors":"David Sánchez Roa, Robert E. Mulvey, Eva Hevia","doi":"10.1021/acscatal.5c08156","DOIUrl":"https://doi.org/10.1021/acscatal.5c08156","url":null,"abstract":"Alkali-metal compounds, particularly organolithium and lithium amide reagents, are indispensable organometallic reagents in synthesis, finding widespread applications in cornerstone stoichiometric organic processes. Recent advances in the development of heavier alkali-metal analogues have revealed their emerging potential not only to participate in stoichiometric processes but also to catalyze transformations traditionally dominated by precious transition metals. This perspective provides an overview of a selection of these applications focusing on hydrogen isotope exchange, alkene isomerization, C–C bond formation, hydrophosphination, and hydrogenation. Special focus is placed on current mechanistic understanding and alkali-metal effects, aiming to draw out key challenges and opportunities that may guide the future development of alkali-metal-mediated catalysis.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"68 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111026","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 : 2026-02-03DOI: 10.1021/acscatal.5c08313
Arjun Kumbhakar, Arup Jyoti Das, Shivhar B. Ambegave, Manoj V. Mane, Nitin T. Patil
Herein, we report the ligand-enabled gold-catalyzed arylative and alkenylative semipinacol rearrangements of allylic alkanols employing aryl and vinyl iodides as coupling partners. Building on our recent success in achieving enantioselective Au(I)/Au(III) redox catalysis using chiral P,N-ligands (ChetPhos), we now report the asymmetric arylative semipinacol rearrangement of allylic alkanols. Due to the strong carbophilic activation ability of gold, the reaction proceeds efficiently with allylic alkanols containing unactivated alkenes, in contrast to previous reports that required activated alkenes. Topographic steric maps, quantified via percentage buried volume (%VBur) analyses of the catalyst, key intermediates, and transition states, elucidate the steric factors governing the enantioinduction. The steric expansion in the South-Eastern (SE) quadrant (%VBur = 98.8%) originates from the twisting of the binaphthyl framework, generating a groove in the North-Eastern (NE) quadrant, facilitating Re-face alkene coordination.
{"title":"Gold-Catalyzed Arylative and Alkenylative Semipinacol Rearrangements: Reaction Development, Mechanistic Insights, and Enantioselective Variant","authors":"Arjun Kumbhakar, Arup Jyoti Das, Shivhar B. Ambegave, Manoj V. Mane, Nitin T. Patil","doi":"10.1021/acscatal.5c08313","DOIUrl":"https://doi.org/10.1021/acscatal.5c08313","url":null,"abstract":"Herein, we report the ligand-enabled gold-catalyzed arylative and alkenylative semipinacol rearrangements of allylic alkanols employing aryl and vinyl iodides as coupling partners. Building on our recent success in achieving enantioselective Au(I)/Au(III) redox catalysis using chiral P,N-ligands (ChetPhos), we now report the asymmetric arylative semipinacol rearrangement of allylic alkanols. Due to the strong carbophilic activation ability of gold, the reaction proceeds efficiently with allylic alkanols containing unactivated alkenes, in contrast to previous reports that required activated alkenes. Topographic steric maps, quantified via percentage buried volume (%<i>V</i><sub>Bur</sub>) analyses of the catalyst, key intermediates, and transition states, elucidate the steric factors governing the enantioinduction. The steric expansion in the South-Eastern (SE) quadrant (%<i>V</i><sub>Bur</sub> = 98.8%) originates from the twisting of the binaphthyl framework, generating a groove in the North-Eastern (NE) quadrant, facilitating <i>Re</i>-face alkene coordination.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"216 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101823","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 : 2026-02-03DOI: 10.1021/acscatal.5c08557
Chen Yang, Adam Poláček, Tjaard Pijning, Marc J. E. C. van der Maarel, Edita Jurak
Glycogen branching enzymes (GBEs) catalyze the formation of α-1,6-glycosidic linkages, introducing branch points into α-glucans such as glycogen and starch. Branch length directly affects the structural, functional, and nutritional properties of these polysaccharides, yet the structural determinants underlying GBE specificity remain incompletely understood. In this study, we investigated the functional roles of three conserved loops─near residues 104, 185, and 454─positioned close to the branch-chain binding groove in the glycoside hydrolase (GH) family 13_8 and GH13_9 GBEs from Anaerococcus prevotii (Ap). Sequence and structural analyses revealed that loop 185 is highly conserved across both subfamilies, while loops 104 and 454 are significantly longer in GH13_8 GBEs, with loop 454 showing the most pronounced difference. To probe their influence on branch length specificity, we engineered ApGBE13_9 by replacing its native loops 104 and 454 with their longer counterparts from ApGBE13_8. Substituting loop 104 alone had no effect on long-branch formation (degree of polymerization (DP) 6–8), while loop 454 replacement shifted activity toward short-branch production (DP 3–4). Dual substitution broadened the branch length range (DP of 3–8), indicating a synergistic interaction between the two loops. Molecular dynamics simulations revealed that the increased flexibility of the longer loop 454 (from ApGBE13_8) perturbs loop 185, causing it to form a “blocked-like” conformation that hinders branch-chain extension within the branch-chain binding groove and promotes the formation of short branches. Long loop 104 acts cooperatively with loop 454 (both from ApGBE13_8), functioning as a dynamic “door” that modulates access to the branch-chain binding groove and enables dual branch length production. These findings provide mechanistic insight into GBE specificity and support rational enzyme engineering for tailored α-glucan synthesis.
{"title":"Key Loops in GH13_8 Subfamily Glycogen Branching Enzymes Modulate Their Branch Length Preference","authors":"Chen Yang, Adam Poláček, Tjaard Pijning, Marc J. E. C. van der Maarel, Edita Jurak","doi":"10.1021/acscatal.5c08557","DOIUrl":"https://doi.org/10.1021/acscatal.5c08557","url":null,"abstract":"Glycogen branching enzymes (GBEs) catalyze the formation of α-1,6-glycosidic linkages, introducing branch points into α-glucans such as glycogen and starch. Branch length directly affects the structural, functional, and nutritional properties of these polysaccharides, yet the structural determinants underlying GBE specificity remain incompletely understood. In this study, we investigated the functional roles of three conserved loops─near residues 104, 185, and 454─positioned close to the branch-chain binding groove in the glycoside hydrolase (GH) family 13_8 and GH13_9 GBEs from <i>Anaerococcus prevotii</i> (Ap). Sequence and structural analyses revealed that loop 185 is highly conserved across both subfamilies, while loops 104 and 454 are significantly longer in GH13_8 GBEs, with loop 454 showing the most pronounced difference. To probe their influence on branch length specificity, we engineered ApGBE13_9 by replacing its native loops 104 and 454 with their longer counterparts from ApGBE13_8. Substituting loop 104 alone had no effect on long-branch formation (degree of polymerization (DP) 6–8), while loop 454 replacement shifted activity toward short-branch production (DP 3–4). Dual substitution broadened the branch length range (DP of 3–8), indicating a synergistic interaction between the two loops. Molecular dynamics simulations revealed that the increased flexibility of the longer loop 454 (from ApGBE13_8) perturbs loop 185, causing it to form a “blocked-like” conformation that hinders branch-chain extension within the branch-chain binding groove and promotes the formation of short branches. Long loop 104 acts cooperatively with loop 454 (both from ApGBE13_8), functioning as a dynamic “door” that modulates access to the branch-chain binding groove and enables dual branch length production. These findings provide mechanistic insight into GBE specificity and support rational enzyme engineering for tailored α-glucan synthesis.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"176 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101824","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 : 2026-02-03DOI: 10.1021/acscatal.5c05370
Shyam Deo, Thomas Ludwig, Wenyu Sun, Brandon C. Wood, Sneha A. Akhade
In heterogeneous catalysis, poisoning by surface-bound intermediates poses a major barrier to sustained catalyst performance in (de)hydrogenation reactions. Formate/bicarbonate systems, as liquid organic hydrogen carriers (LOHCs), offer a CO2-integrated, low-temperature pathway for hydrogen storage and release, making them attractive for circular energy applications. However, their lower hydrogen density and susceptibility to catalyst deactivation limit their competitiveness compared to conventional LOHCs like methylcyclohexane. This study investigates the mechanistic origins of formate (HCOO–) dehydrogenation and associated deactivation on Pd interfaces. Using density functional theory (DFT) simulations, we show that under thermocatalytic conditions, strongly bound formate accumulates on the catalyst surface (Pd(111)), blocking active sites, raising activation barriers, and leading to progressive performance loss. Because formate adsorption involves charge transfer, we exploit its sensitivity to electronic structure by modulating the electrochemical potential of the catalyst. Our results reveal that hydrogen transfer from water and formate exhibits opposing potential dependencies, providing insights into the opposing driving forces behind both catalytic activity and poisoning. To further probe this phenomenon, we examine electrochemically induced phase transitions in Pd, focusing on PdO(100) and PdH(110), which are stable under oxidizing and reducing potentials, respectively, and demonstrate enhanced dehydrogenation activity between −0.4 and 0.2 V vs standard hydrogen electrode (SHE). Complementary thermal treatments help decouple kinetic and thermodynamic contributions to intermediate binding. These findings underscore the critical role of the catalyst phase and external stimuli in dictating poison-active site interactions and highlight phase engineering as a promising strategy to mitigate deactivation. This work offers mechanistic insights and design principles for developing more resilient and efficient catalysts for LOHC applications under realistic operating conditions.
在多相催化中，表面结合的中间体中毒是维持（脱）氢化反应中催化剂性能的主要障碍。甲酸盐/碳酸氢盐体系作为液态有机氢载体（lohc），为氢的储存和释放提供了二氧化碳集成的低温途径，使其在循环能源应用中具有吸引力。然而，与甲基环己烷等传统lohc相比，它们较低的氢密度和对催化剂失活的敏感性限制了它们的竞争力。本研究探讨了甲酸酯（HCOO -）脱氢和Pd界面失活的机理起源。利用密度泛函理论（DFT）模拟，我们发现在热催化条件下，强结合的甲酸盐在催化剂表面积累（Pd(111)），阻塞活性位点，提高激活障碍，导致性能逐渐丧失。由于甲酸吸附涉及电荷转移，我们通过调节催化剂的电化学电位来利用其对电子结构的敏感性。我们的研究结果表明，水和甲酸的氢转移表现出相反的潜在依赖性，为催化活性和中毒背后的相反驱动力提供了见解。为了进一步探讨这一现象，我们研究了Pd中电化学诱导的相变，重点研究了PdO（100）和PdH(110)，它们分别在氧化电位和还原电位下稳定，并且在- 0.4和0.2 V vs标准氢电极（SHE）之间表现出增强的脱氢活性。补充热处理有助于解耦中间结合的动力学和热力学贡献。这些发现强调了催化剂阶段和外部刺激在决定毒素活性位点相互作用中的关键作用，并强调了阶段工程作为减轻失活的有希望的策略。这项工作为在实际操作条件下开发更具弹性和高效的LOHC应用催化剂提供了机理见解和设计原则。
{"title":"Modulating Operational Conditions to Mitigate Deactivation in Formate Dehydrogenation on Pd Phases","authors":"Shyam Deo, Thomas Ludwig, Wenyu Sun, Brandon C. Wood, Sneha A. Akhade","doi":"10.1021/acscatal.5c05370","DOIUrl":"https://doi.org/10.1021/acscatal.5c05370","url":null,"abstract":"In heterogeneous catalysis, poisoning by surface-bound intermediates poses a major barrier to sustained catalyst performance in (de)hydrogenation reactions. Formate/bicarbonate systems, as liquid organic hydrogen carriers (LOHCs), offer a CO<sub>2</sub>-integrated, low-temperature pathway for hydrogen storage and release, making them attractive for circular energy applications. However, their lower hydrogen density and susceptibility to catalyst deactivation limit their competitiveness compared to conventional LOHCs like methylcyclohexane. This study investigates the mechanistic origins of formate (<i>HCOO</i><sup>–</sup>) dehydrogenation and associated deactivation on Pd interfaces. Using density functional theory (DFT) simulations, we show that under thermocatalytic conditions, strongly bound formate accumulates on the catalyst surface (Pd(111)), blocking active sites, raising activation barriers, and leading to progressive performance loss. Because formate adsorption involves charge transfer, we exploit its sensitivity to electronic structure by modulating the electrochemical potential of the catalyst. Our results reveal that hydrogen transfer from water and formate exhibits opposing potential dependencies, providing insights into the opposing driving forces behind both catalytic activity and poisoning. To further probe this phenomenon, we examine electrochemically induced phase transitions in Pd, focusing on PdO(100) and PdH(110), which are stable under oxidizing and reducing potentials, respectively, and demonstrate enhanced dehydrogenation activity between −0.4 and 0.2 V vs standard hydrogen electrode (SHE). Complementary thermal treatments help decouple kinetic and thermodynamic contributions to intermediate binding. These findings underscore the critical role of the catalyst phase and external stimuli in dictating poison-active site interactions and highlight phase engineering as a promising strategy to mitigate deactivation. This work offers mechanistic insights and design principles for developing more resilient and efficient catalysts for LOHC applications under realistic operating conditions.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"5 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101821","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 : 2026-02-03DOI: 10.1021/acscatal.6c00039
Pengyue Jin, Xinhuan Xu, Daniella Hübner, Yongli Yan, Cui Wang
Photoactive iron complexes present highly desirable and accessible alternatives to the well-known noble metal complex-based photocatalysts, thanks to iron’s high abundance, low toxicity, and minimal environmental impact. Recent breakthroughs with luminescent 3d5 FeIII complexes show that their doublet ligand-to-metal charge transfer (2LMCT) excited states readily facilitate electron transfer and photoredox catalysis. However, their utilization in energy transfer-based photophysics and photochemistry remains underexplored. This study demonstrates that the luminescent [Fe(phtmeimb)2]PF6 complex (FeIII) sensitizes efficient doublet-triplet energy transfer to 9,10-bis((triisopropylsilyl)ethynyl)anthracene (AnTIPS) that is photoredox active. This process benefits greatly from their ground state preassociation, ultimately achieving green-to-blue upconversion. The FeIII/AnTIPS upconversion pair facilitated photoredox catalytic dehalogenation of phenacyl halides with high product yields of 66–74% under green light irradiation. Encapsulation of the FeIII/AnTIPS pair onto polystyrene nanoparticles gave water-stable hybrid nanocatalysts PS(FeIII/AnTIPS) with high photostability, which enabled near-quantitative photocatalytic polymerization of acrylate monomers in an aqueous environment. For these photochemical transformations, the FeIII/AnTIPS upconversion pair exhibits substantially higher catalytic activity than the FeIII complex or AnTIPS alone under identical reaction conditions. This work establishes a powerful photocatalytic platform based on iron complex-sensitized photon upconversion for demanding chemical reactions and facilitates iron-based hybrid nanocatalysts for aqueous photocatalysis, marking an important step toward emerging energy conversion technologies.
{"title":"Beyond the Diffusion Limit: Preassociation Enhanced Photon Upconversion and Photocatalysis Sensitized by Iron Complex","authors":"Pengyue Jin, Xinhuan Xu, Daniella Hübner, Yongli Yan, Cui Wang","doi":"10.1021/acscatal.6c00039","DOIUrl":"https://doi.org/10.1021/acscatal.6c00039","url":null,"abstract":"Photoactive iron complexes present highly desirable and accessible alternatives to the well-known noble metal complex-based photocatalysts, thanks to iron’s high abundance, low toxicity, and minimal environmental impact. Recent breakthroughs with luminescent 3d<sup>5</sup> Fe<sup>III</sup> complexes show that their doublet ligand-to-metal charge transfer (<sup>2</sup>LMCT) excited states readily facilitate electron transfer and photoredox catalysis. However, their utilization in energy transfer-based photophysics and photochemistry remains underexplored. This study demonstrates that the luminescent [Fe(phtmeimb)<sub>2</sub>]PF<sub>6</sub> complex (Fe<sup>III</sup>) sensitizes efficient doublet-triplet energy transfer to 9,10-bis((triisopropylsilyl)ethynyl)anthracene (AnTIPS) that is photoredox active. This process benefits greatly from their ground state preassociation, ultimately achieving green-to-blue upconversion. The Fe<sup>III</sup>/AnTIPS upconversion pair facilitated photoredox catalytic dehalogenation of phenacyl halides with high product yields of 66–74% under green light irradiation. Encapsulation of the Fe<sup>III</sup>/AnTIPS pair onto polystyrene nanoparticles gave water-stable hybrid nanocatalysts PS(Fe<sup>III</sup>/AnTIPS) with high photostability, which enabled near-quantitative photocatalytic polymerization of acrylate monomers in an aqueous environment. For these photochemical transformations, the Fe<sup>III</sup>/AnTIPS upconversion pair exhibits substantially higher catalytic activity than the Fe<sup>III</sup> complex or AnTIPS alone under identical reaction conditions. This work establishes a powerful photocatalytic platform based on iron complex-sensitized photon upconversion for demanding chemical reactions and facilitates iron-based hybrid nanocatalysts for aqueous photocatalysis, marking an important step toward emerging energy conversion technologies.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"68 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110687","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 : 2026-02-03DOI: 10.1021/acscatal.5c07893
Qiliang Liu, Wenxing Yang
Recently, an intense Raman peak at approximately 520–544 cm–1 (briefly named as *530 in this study) has been widely observed and discussed during in situ spectroscopic studies of electrochemical CO2 or CO reduction reaction (CO(2)RR). Several mechanisms were proposed to explain the nature of this peak, most notably attributing it to Cu–OHad or CuOx(OH)y, which was then utilized as a key spectroscopic indicator in various mechanistic discussions. Herein, by systematic isotopic-labeled spectroscopic studies, we show that the nature of the *530 peak may not be the previously proposed species, but more likely a surface species containing (C, O) in equilibrium with inert bridging-type adsorbed CO (*CObridge). Both the formation of *530 and *CObridge is shown to be associated with the spontaneous reconstruction of Cu. The *CObridge and *530 Raman modes share the same adsorption sites and can interconvert into each other via the variation of electrochemical potentials. Finally, the appearance of both peaks is shown to signalize a deteriorated C2+ products performance of CO2RR and CORR. These results update the current understandings of the role of *530 for CO(2)RR. It also highlights that the emerging-recognized electrocatalyst reconstruction phenomenon can be accompanied by the formation of diverse surface adsorbates, casting challenges, and necessitating rigorous spectroscopic studies for better mechanistic understanding.
{"title":"Revisiting the Nature and Catalytic Role of the 530 cm–1 Raman Peak on Cu Catalysts during CO(2) Electroreduction","authors":"Qiliang Liu, Wenxing Yang","doi":"10.1021/acscatal.5c07893","DOIUrl":"https://doi.org/10.1021/acscatal.5c07893","url":null,"abstract":"Recently, an intense Raman peak at approximately 520–544 cm<sup>–1</sup> (briefly named as *530 in this study) has been widely observed and discussed during in situ spectroscopic studies of electrochemical CO<sub>2</sub> or CO reduction reaction (CO<sub>(2)</sub>RR). Several mechanisms were proposed to explain the nature of this peak, most notably attributing it to Cu–OH<sub>ad</sub> or CuO<sub><i>x</i></sub>(OH)<sub><i>y</i></sub>, which was then utilized as a key spectroscopic indicator in various mechanistic discussions. Herein, by systematic isotopic-labeled spectroscopic studies, we show that the nature of the *530 peak may not be the previously proposed species, but more likely a surface species containing (C, O) in equilibrium with inert bridging-type adsorbed CO (*CO<sub>bridge</sub>)<sub>.</sub> Both the formation of *530 and *CO<sub>bridge</sub> is shown to be associated with the spontaneous reconstruction of Cu. The *CO<sub>bridge</sub> and *530 Raman modes share the same adsorption sites and can interconvert into each other via the variation of electrochemical potentials. Finally, the appearance of both peaks is shown to signalize a deteriorated C<sub>2+</sub> products performance of CO<sub>2</sub>RR and CORR. These results update the current understandings of the role of *530 for CO<sub>(2)</sub>RR. It also highlights that the emerging-recognized electrocatalyst reconstruction phenomenon can be accompanied by the formation of diverse surface adsorbates, casting challenges, and necessitating rigorous spectroscopic studies for better mechanistic understanding.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"8 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110683","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 : 2026-02-03DOI: 10.1021/acscatal.5c08221
Jack T. Floreancig, Marco A. Lopez, Allison R. Dick, Luana Cardinale, Nicole C. Goodwin, Darren L. Poole, Shannon S. Stahl
Synthetic methods that use C(sp3)–H bonds in carbon–carbon cross-coupling reactions are limited and often lack generality, particularly with substrates containing basic heterocycles. Here, we demonstrate the arylation of heterobenzylic C–H bonds by using heterobenzyl chlorides as linchpins that can undergo Ni-catalyzed cross-electrophile coupling with aryl iodides. The results show different reactivity for primary and secondary heterobenzyl chlorides and also show differences among secondary heterobenzyl chlorides at different positions on the heteroaromatic ring. The Ni-catalyzed conditions identified for each of these substrate classes ensure that the rate of heterobenzyl chloride activation complements the rate of aryl iodide activation. These methods are demonstrated with series of heterobenzyl chlorides and (hetero)aryl iodides, providing a general strategy for C(sp3)–H arylation.
{"title":"Heterobenzyl Chlorides as Linchpins for C–H Arylation via Sequential C–H Chlorination/Cross-Electrophile Coupling","authors":"Jack T. Floreancig, Marco A. Lopez, Allison R. Dick, Luana Cardinale, Nicole C. Goodwin, Darren L. Poole, Shannon S. Stahl","doi":"10.1021/acscatal.5c08221","DOIUrl":"https://doi.org/10.1021/acscatal.5c08221","url":null,"abstract":"Synthetic methods that use C(sp<sup>3</sup>)–H bonds in carbon–carbon cross-coupling reactions are limited and often lack generality, particularly with substrates containing basic heterocycles. Here, we demonstrate the arylation of heterobenzylic C–H bonds by using heterobenzyl chlorides as linchpins that can undergo Ni-catalyzed cross-electrophile coupling with aryl iodides. The results show different reactivity for primary and secondary heterobenzyl chlorides and also show differences among secondary heterobenzyl chlorides at different positions on the heteroaromatic ring. The Ni-catalyzed conditions identified for each of these substrate classes ensure that the rate of heterobenzyl chloride activation complements the rate of aryl iodide activation. These methods are demonstrated with series of heterobenzyl chlorides and (hetero)aryl iodides, providing a general strategy for C(sp<sup>3</sup>)–H arylation.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"90 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110684","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 direct capture and methanation of CO2 from ambient air is traditionally conducted over dual-function materials containing at least two distinct elements─a CO2 binding site that facilitates concentration of CO2 at a gas–solid interface, and an active site that converts said adsorbed CO2 to methane through reaction with gas-phase hydrogen. We report herein the use of extralattice oxygen defects on unary and binary extended NiO surfaces to create a single-component dual-function material that, in its partially reduced form, effects both desired functions: adsorption and methanation. Specifically, we show how excess oxygen-derived recalcitrant carbonates─purportedly bidentate in configuration─can persist on oxide surfaces well into the methanation temperature range, and also be conferred the propensity for reactive desorption to form methane. Reactive desorption of these recalcitrant carbonates facilitates methanation at temperatures significantly lower than is typical for existing capture and methanation systems, and renders the CO2 concentration-reaction scheme to be limited by kinetic barriers associated with its activation, rather than its desorption. High-valent doping perturbs surface acid–base properties in a manner that concurrently destabilizes oxygen vacancies and stabilizes excess oxygens, enabling redressal of two principal challenges encumbering the design of capture and conversion materials, namely, cyclic stability and low-temperature methane productivity. Non-synthetic strategies for extralattice oxygen defect creation, including thermal treatments in inert streams, also help provide the requisite bidentate carbonate densities, suggesting transition-metal oxides as a tunable, noble-metal-free platform for the capture and conversion of CO2 from ambient air into value-added products such as methane. The data presented also reveal aliovalent dopant density, excess oxygen content, and carbonate denticity as readily accessible variables that enable amplification of the separations and catalysis performance of extended oxide surfaces.
{"title":"Kinetically Constrained Capture and Conversion of CO2 from Ambient Air Using Excess Oxygen-Derived Recalcitrant Carbonates","authors":"Xiaowei Wu, Rahul Pandey, Ramanan Krishnamoorti, Praveen Bollini","doi":"10.1021/acscatal.5c08102","DOIUrl":"https://doi.org/10.1021/acscatal.5c08102","url":null,"abstract":"The direct capture and methanation of CO<sub>2</sub> from ambient air is traditionally conducted over dual-function materials containing at least two distinct elements─a CO<sub>2</sub> binding site that facilitates concentration of CO<sub>2</sub> at a gas–solid interface, and an active site that converts said adsorbed CO<sub>2</sub> to methane through reaction with gas-phase hydrogen. We report herein the use of extralattice oxygen defects on unary and binary extended NiO surfaces to create a single-component dual-function material that, in its partially reduced form, effects both desired functions: adsorption and methanation. Specifically, we show how excess oxygen-derived recalcitrant carbonates─purportedly bidentate in configuration─can persist on oxide surfaces well into the methanation temperature range, and also be conferred the propensity for reactive desorption to form methane. Reactive desorption of these recalcitrant carbonates facilitates methanation at temperatures significantly lower than is typical for existing capture and methanation systems, and renders the CO<sub>2</sub> concentration-reaction scheme to be limited by kinetic barriers associated with its activation, rather than its desorption. High-valent doping perturbs surface acid–base properties in a manner that concurrently destabilizes oxygen vacancies and stabilizes excess oxygens, enabling redressal of two principal challenges encumbering the design of capture and conversion materials, namely, cyclic stability and low-temperature methane productivity. Non-synthetic strategies for extralattice oxygen defect creation, including thermal treatments in inert streams, also help provide the requisite bidentate carbonate densities, suggesting transition-metal oxides as a tunable, noble-metal-free platform for the capture and conversion of CO<sub>2</sub> from ambient air into value-added products such as methane. The data presented also reveal aliovalent dopant density, excess oxygen content, and carbonate denticity as readily accessible variables that enable amplification of the separations and catalysis performance of extended oxide surfaces.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"88 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146111025","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}
Stereoselective hydrogenation provides a concise way for the synthesis of compounds with multiple stereocenters, but stereoselectivity control is particularly challenging on the surface of bare supported metal nanoparticles (NPs). In this work, a series of supported Pd NPs were synthesized and used for the diastereoselective hydrogenation of (−)-terpinen-4-ol. It is found that diastereoselectivity is strongly related to the size of Pd: Pd NPs with a big size favor hydrogenation from the hydroxyl face, and a diastereomeric ratio (dr) of 95:5 was obtained with a Pd size of 27.9 nm. Kinetic and calculation results suggest that the highly coordinated Pd sites assist in stabilizing the transition state when the substrate is adsorbed from the hydroxyl face. Thus, the observed diastereoselectivity could be related to the different ratios of highly coordinated Pd sites over Pd NPs of different sizes. We hope the insights obtained in this work could provide fundamental principles for dealing with structure sensitive reactions.
{"title":"Diastereocontrol in Hydroxyl-Directed Hydrogenation: Deciphering the Size-Selectivity Relationship of Supported Pd Nanoparticles","authors":"Yujie Tang, Kefu Zhao, Yuantao Cai, Yushan Xu, Maodi Wang, Huicong Dai, Qihua Yang","doi":"10.1021/acscatal.5c08591","DOIUrl":"https://doi.org/10.1021/acscatal.5c08591","url":null,"abstract":"Stereoselective hydrogenation provides a concise way for the synthesis of compounds with multiple stereocenters, but stereoselectivity control is particularly challenging on the surface of bare supported metal nanoparticles (NPs). In this work, a series of supported Pd NPs were synthesized and used for the diastereoselective hydrogenation of (−)-terpinen-4-ol. It is found that diastereoselectivity is strongly related to the size of Pd: Pd NPs with a big size favor hydrogenation from the hydroxyl face, and a diastereomeric ratio (dr) of 95:5 was obtained with a Pd size of 27.9 nm. Kinetic and calculation results suggest that the highly coordinated Pd sites assist in stabilizing the transition state when the substrate is adsorbed from the hydroxyl face. Thus, the observed diastereoselectivity could be related to the different ratios of highly coordinated Pd sites over Pd NPs of different sizes. We hope the insights obtained in this work could provide fundamental principles for dealing with structure sensitive reactions.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"84 1","pages":""},"PeriodicalIF":12.9,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110685","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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