Pub Date : 2024-09-20DOI: 10.1021/acsorginorgau.4c00045
Limashree Sahoo, Payal Panwar, Chivukula V. Sastri, Sam P. de Visser
The first-coordination sphere of catalysts is known to play a crucial role in reaction mechanisms, but details of how equatorial ligands influence the reactivity remain unknown. Heteroatom ligated to the equatorial position of iron centers in nonheme iron metalloenzymes modulates structure and reactivity. To investigate the impact of equatorial heteroatom substitution on chlorite oxidation, we synthesized and characterized three novel mononuclear nonheme iron(II) complexes with a pentadentate bispidine scaffold. These complexes feature systematic substitutions at the equatorial position in the bispidine ligand framework where the pyridine group is replaced with NMe2, SMe, and OMe groups. The three iron(II)–bispidine complexes were subjected to studies in chlorite oxidation reactions as a model pathway for oxygen atom transfer. Chlorine oxyanions, which have the halide in an oxidation state ranging from +1 to +7, have numerous applications but can contaminate water bodies, and this demands urgent environmental remediation. Chlorite, a common precursor to chlorine dioxide, is of particular interest due to the superior antimicrobial activity of chlorine dioxide. Moreover, its generation leads to fewer harmful byproducts in water treatment. Here, we demonstrate that these complexes can produce chlorine dioxide from chlorite in acetate buffer at room temperature and pH 5.0, oxidizing chlorite through the in situ formation of high-valent iron(IV)–oxo intermediates. This study establishes how subtle changes in the coordination sphere around iron can influence the reactivity.
{"title":"Unraveling Chlorite Oxidation Pathways in Equatorially Heteroatom-Substituted Nonheme Iron Complexes","authors":"Limashree Sahoo, Payal Panwar, Chivukula V. Sastri, Sam P. de Visser","doi":"10.1021/acsorginorgau.4c00045","DOIUrl":"https://doi.org/10.1021/acsorginorgau.4c00045","url":null,"abstract":"The first-coordination sphere of catalysts is known to play a crucial role in reaction mechanisms, but details of how equatorial ligands influence the reactivity remain unknown. Heteroatom ligated to the equatorial position of iron centers in nonheme iron metalloenzymes modulates structure and reactivity. To investigate the impact of equatorial heteroatom substitution on chlorite oxidation, we synthesized and characterized three novel mononuclear nonheme iron(II) complexes with a pentadentate bispidine scaffold. These complexes feature systematic substitutions at the equatorial position in the bispidine ligand framework where the pyridine group is replaced with NMe<sub>2</sub>, SMe, and OMe groups. The three iron(II)–bispidine complexes were subjected to studies in chlorite oxidation reactions as a model pathway for oxygen atom transfer. Chlorine oxyanions, which have the halide in an oxidation state ranging from +1 to +7, have numerous applications but can contaminate water bodies, and this demands urgent environmental remediation. Chlorite, a common precursor to chlorine dioxide, is of particular interest due to the superior antimicrobial activity of chlorine dioxide. Moreover, its generation leads to fewer harmful byproducts in water treatment. Here, we demonstrate that these complexes can produce chlorine dioxide from chlorite in acetate buffer at room temperature and pH 5.0, oxidizing chlorite through the in situ formation of high-valent iron(IV)–oxo intermediates. This study establishes how subtle changes in the coordination sphere around iron can influence the reactivity.","PeriodicalId":29797,"journal":{"name":"ACS Organic & Inorganic Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.1021/acsorginorgau.4c00044
Henry P. DeGroot, Isaiah R. Speight, William W. Brennessel, Timothy P. Hanusa
Metal complexes with t-Bu-substituted allyl ligands are relatively rare, especially compared to their conceptually similar trimethylsilyl-substituted analogs. The scarcity partially stems from the few general synthetic entry points for the t-Bu versions. This situation was studied through a modified synthesis for the allyl ligand itself and by forming several mono(allyl)nickel derivatives. After 2,2,6,6-tetramethyl-4-hepten-3-one was converted to the related 5-bromo-2,2,6,6-tetramethylhept-3-ene (A2tBr), a mixture of Ni(COD)2 and A2tBr in the presence of a neutral donor ligand such as MeCN was found to produce the dark red dimeric π-allyl complex [{A2tNiBr}2]. Both NMR and X-ray crystallographic data confirmed that the t-Bu substituents are in a syn, syn-conformation, like that in the previously described [{A′NiBr}2] (A′ = 1,3-(TMS)2C3H3) complex. [{A2tNiBr}2] will form adducts with neutral donors such as PPh3 and IMes (IMes = 1,3-dimesitylimidazol-2-ylidene), but the resulting [A2tNi(PPh3)Br] complex is not as stable as its trimethylsilyl analog. The [A2tNi(IMes)Br] complex crystallizes from hexanes as a monomer, with an η3-coordinated [A2t] ligand, and in contrast to the starting arrangement in [{A2tNiBr}2], the t-Bu groups on the A2t ligand are in a syn, anti-relationship. This structure is paralleled in the trimethylsilyl analog [A′Ni(IMes)Br]. DFT calculations were used to compare the structures of t-Bu- and related trimethylsilyl-substituted complexes.
{"title":"t-Butyl and Trimethylsilyl Substituents in Nickel Allyl Complexes: Similar but Not the Same","authors":"Henry P. DeGroot, Isaiah R. Speight, William W. Brennessel, Timothy P. Hanusa","doi":"10.1021/acsorginorgau.4c00044","DOIUrl":"https://doi.org/10.1021/acsorginorgau.4c00044","url":null,"abstract":"Metal complexes with <i>t</i>-Bu-substituted allyl ligands are relatively rare, especially compared to their conceptually similar trimethylsilyl-substituted analogs. The scarcity partially stems from the few general synthetic entry points for the <i>t</i>-Bu versions. This situation was studied through a modified synthesis for the allyl ligand itself and by forming several mono(allyl)nickel derivatives. After 2,2,6,6-tetramethyl-4-hepten-3-one was converted to the related 5-bromo-2,2,6,6-tetramethylhept-3-ene (A<sup>2t</sup>Br), a mixture of Ni(COD)<sub>2</sub> and A<sup>2t</sup>Br in the presence of a neutral donor ligand such as MeCN was found to produce the dark red dimeric π-allyl complex [{A<sup>2t</sup>NiBr}<sub>2</sub>]. Both NMR and X-ray crystallographic data confirmed that the <i>t</i>-Bu substituents are in a <i>syn</i>, <i>syn</i>-conformation, like that in the previously described [{A′NiBr}<sub>2</sub>] (A′ = 1,3-(TMS)<sub>2</sub>C<sub>3</sub>H<sub>3</sub>) complex. [{A<sup>2t</sup>NiBr}<sub>2</sub>] will form adducts with neutral donors such as PPh<sub>3</sub> and IMes (IMes = 1,3-dimesitylimidazol-2-ylidene), but the resulting [A<sup>2t</sup>Ni(PPh<sub>3</sub>)Br] complex is not as stable as its trimethylsilyl analog. The [A<sup>2t</sup>Ni(IMes)Br] complex crystallizes from hexanes as a monomer, with an η<sup>3</sup>-coordinated [A<sup>2t</sup>] ligand, and in contrast to the starting arrangement in [{A<sup>2t</sup>NiBr}<sub>2</sub>], the <i>t</i>-Bu groups on the A<sup>2t</sup> ligand are in a <i>syn</i>, <i>anti-</i>relationship. This structure is paralleled in the trimethylsilyl analog [A′Ni(IMes)Br]. DFT calculations were used to compare the structures of <i>t</i>-Bu- and related trimethylsilyl-substituted complexes.","PeriodicalId":29797,"journal":{"name":"ACS Organic & Inorganic Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-05DOI: 10.1021/acsorginorgau.4c00057
Fellipe F. S. Farias, Mateus Mittersteiner, Amanda M. Kieling, Priscila S. V. Lima, Gustavo H. Weimer, Helio G. Bonacorso, Nilo Zanatta, Marcos A. P. Martins
Pyrimidinone scaffolds are present in a wide array of molecules with synthetic and pharmacological utility. The inherent properties of these compounds may be attributed to intermolecular interactions analogous to the interactions that molecules tend to establish with active sites. Pyrimidinones and their fused derivatives have garnered significant interest due to their structural features, which resemble nitrogenous bases, the foundational building blocks of DNA and RNA. Similarly, pyrimidinones are predisposed to forming N–H···O hydrogen bonds akin to nitrogenous bases. Given this context, this study explored the supramolecular features and the predisposition to form hydrogen bonds in a series of 18 substituted 4-(trihalomethyl)-2(1H)-pyrimidinones. The formation of hydrogen bonds was observed in solution via nuclear magnetic resonance (NMR) spectroscopy experiments, and subsequently confirmed in the crystalline solid state. Hence, the 18 compounds were crystallized through crystallization assays by slow solvent evaporation, followed by single-crystal X-ray diffraction (SC-XRD). The supramolecular cluster demarcation was employed to evaluate all intermolecular interactions, and all crystalline structures exhibited robust hydrogen bonds, with an average energy of approximately −21.64 kcal mol–1 (∼19% of the total stabilization energy of the supramolecular clusters), irrespective of the substituents at positions 4, 5, or 6 of the pyrimidinone core. To elucidate the nature of these hydrogen bonds, an analysis based on the quantum theory of atoms in molecules (QTAIM) revealed that the predominant intermolecular interactions are N–H···O (average of −16.55 kcal mol–1) and C–H···O (average of −6.48 kcal mol–1). Through proposing crystallization mechanisms based on molecular stabilization energy data and contact areas between molecules and employing the supramolecular cluster and retrocrystallization concepts, it was determined that altering the halogen (F/Cl) at position 4 of the pyrimidinone nucleus modifies the crystallization mechanism pathway. Notably, the hydrogen bonds present in the initial proposed steps were confirmed by 1H NMR experiments using concentration-dependent techniques.
{"title":"The Persistence of Hydrogen Bonds in Pyrimidinones: From Solution to Crystal","authors":"Fellipe F. S. Farias, Mateus Mittersteiner, Amanda M. Kieling, Priscila S. V. Lima, Gustavo H. Weimer, Helio G. Bonacorso, Nilo Zanatta, Marcos A. P. Martins","doi":"10.1021/acsorginorgau.4c00057","DOIUrl":"https://doi.org/10.1021/acsorginorgau.4c00057","url":null,"abstract":"Pyrimidinone scaffolds are present in a wide array of molecules with synthetic and pharmacological utility. The inherent properties of these compounds may be attributed to intermolecular interactions analogous to the interactions that molecules tend to establish with active sites. Pyrimidinones and their fused derivatives have garnered significant interest due to their structural features, which resemble nitrogenous bases, the foundational building blocks of DNA and RNA. Similarly, pyrimidinones are predisposed to forming N–H···O hydrogen bonds akin to nitrogenous bases. Given this context, this study explored the supramolecular features and the predisposition to form hydrogen bonds in a series of 18 substituted 4-(trihalomethyl)-2(1<i>H</i>)-pyrimidinones. The formation of hydrogen bonds was observed in solution via nuclear magnetic resonance (NMR) spectroscopy experiments, and subsequently confirmed in the crystalline solid state. Hence, the 18 compounds were crystallized through crystallization assays by slow solvent evaporation, followed by single-crystal X-ray diffraction (SC-XRD). The supramolecular cluster demarcation was employed to evaluate all intermolecular interactions, and all crystalline structures exhibited robust hydrogen bonds, with an average energy of approximately −21.64 kcal mol<sup>–1</sup> (∼19% of the total stabilization energy of the supramolecular clusters), irrespective of the substituents at positions 4, 5, or 6 of the pyrimidinone core. To elucidate the nature of these hydrogen bonds, an analysis based on the quantum theory of atoms in molecules (QTAIM) revealed that the predominant intermolecular interactions are N–H···O (average of −16.55 kcal mol<sup>–1</sup>) and C–H···O (average of −6.48 kcal mol<sup>–1</sup>). Through proposing crystallization mechanisms based on molecular stabilization energy data and contact areas between molecules and employing the supramolecular cluster and retrocrystallization concepts, it was determined that altering the halogen (F/Cl) at position 4 of the pyrimidinone nucleus modifies the crystallization mechanism pathway. Notably, the hydrogen bonds present in the initial proposed steps were confirmed by <sup>1</sup>H NMR experiments using concentration-dependent techniques.","PeriodicalId":29797,"journal":{"name":"ACS Organic & Inorganic Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-29DOI: 10.1021/acsorginorgau.4c00052
Maisa Faour, Karam Yassin, Dario R. Dekel
Anion-exchange membranes (AEMs), known for enabling the high conductivity of hydroxide anions through dense polymeric structures, are pivotal components in fuel cells, electrolyzers, and other important electrochemical systems. This paper unveils an unprecedented utilization of AEMs in an electrochemical oxygen separation process, a new technology able to generate enriched oxygen from an O2/N2 mixture using a small voltage input. We demonstrate a first-of-its-kind AEM-based electrochemical device that operates under mild conditions, is free of liquid electrolytes or sweep gases, and produces oxygen of over 96% purity. Additionally, we develop and apply a one-dimensional time-dependent and isothermal model, which accurately captures the unique operational dynamics of our device, demonstrates good agreement with the experimental data, and allows us to explore the device’s potential capabilities. This novel technology has far-reaching applications in many industrial processes, medical oxygen therapy, and other diverse fields while reducing operational complexity and environmental impact, thereby paving the way for sustainable on-site oxygen generation.
{"title":"Anion-Exchange Membrane Oxygen Separator","authors":"Maisa Faour, Karam Yassin, Dario R. Dekel","doi":"10.1021/acsorginorgau.4c00052","DOIUrl":"https://doi.org/10.1021/acsorginorgau.4c00052","url":null,"abstract":"Anion-exchange membranes (AEMs), known for enabling the high conductivity of hydroxide anions through dense polymeric structures, are pivotal components in fuel cells, electrolyzers, and other important electrochemical systems. This paper unveils an unprecedented utilization of AEMs in an electrochemical oxygen separation process, a new technology able to generate enriched oxygen from an O<sub>2</sub>/N<sub>2</sub> mixture using a small voltage input. We demonstrate a first-of-its-kind AEM-based electrochemical device that operates under mild conditions, is free of liquid electrolytes or sweep gases, and produces oxygen of over 96% purity. Additionally, we develop and apply a one-dimensional time-dependent and isothermal model, which accurately captures the unique operational dynamics of our device, demonstrates good agreement with the experimental data, and allows us to explore the device’s potential capabilities. This novel technology has far-reaching applications in many industrial processes, medical oxygen therapy, and other diverse fields while reducing operational complexity and environmental impact, thereby paving the way for sustainable on-site oxygen generation.","PeriodicalId":29797,"journal":{"name":"ACS Organic & Inorganic Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-17DOI: 10.1021/acsorginorgau.4c00034
Corina Stoian, Fawaz Al Hussein, Wesley R. Browne, Emanuel Hupf, Jens Beckmann
From a fundamental perspective, studies of novel mixed-valent complexes containing ferrocenyl units are motivated by the prospect of improving and extending electron transfer models and theories. Here, the series of triferrocenylpnictogens Fc3E was extended to the heavier analogues (E = As, Sb, and Bi), and the influence of the bridging atom was investigated with Fc3P as a reference. Electrochemical studies elucidate the effect of electrostatic contribution on the large redox splitting (ΔE1) exhibited by the compounds and solvent stabilization in the case of Fc3As. Structural characterization of the triferrocenylpnictogens combined with spectroelectrochemical studies indicates weak electronic couplings in the related cations [Fc3E]+, suggesting a through-space mechanism.
{"title":"Electronic Coupling in Triferrocenylpnictogens","authors":"Corina Stoian, Fawaz Al Hussein, Wesley R. Browne, Emanuel Hupf, Jens Beckmann","doi":"10.1021/acsorginorgau.4c00034","DOIUrl":"https://doi.org/10.1021/acsorginorgau.4c00034","url":null,"abstract":"From a fundamental perspective, studies of novel mixed-valent complexes containing ferrocenyl units are motivated by the prospect of improving and extending electron transfer models and theories. Here, the series of triferrocenylpnictogens Fc<sub>3</sub>E was extended to the heavier analogues (E = As, Sb, and Bi), and the influence of the bridging atom was investigated with Fc<sub>3</sub>P as a reference. Electrochemical studies elucidate the effect of electrostatic contribution on the large redox splitting (Δ<i>E</i><sub>1</sub>) exhibited by the compounds and solvent stabilization in the case of Fc<sub>3</sub>As. Structural characterization of the triferrocenylpnictogens combined with spectroelectrochemical studies indicates weak electronic couplings in the related cations [Fc<sub>3</sub>E]<sup>+</sup>, suggesting a through-space mechanism.","PeriodicalId":29797,"journal":{"name":"ACS Organic & Inorganic Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-07DOI: 10.1021/acsorginorgau.4c00001
Javier F. Reynes, Felix Leon, Felipe García
In recent years, mechanochemistry has become an innovative and sustainable alternative to traditional solvent-based synthesis. Mechanochemistry rapidly expanded across a wide range of chemistry fields, including diverse organic compounds and active pharmaceutical ingredients, coordination compounds, organometallic complexes, main group frameworks, and technologically relevant materials. This Review aims to highlight recent advancements and accomplishments in mechanochemistry, underscoring its potential as a viable and eco-friendly alternative to conventional solution-based methods in the field of synthetic chemistry.
{"title":"Mechanochemistry for Organic and Inorganic Synthesis","authors":"Javier F. Reynes, Felix Leon, Felipe García","doi":"10.1021/acsorginorgau.4c00001","DOIUrl":"https://doi.org/10.1021/acsorginorgau.4c00001","url":null,"abstract":"In recent years, mechanochemistry has become an innovative and sustainable alternative to traditional solvent-based synthesis. Mechanochemistry rapidly expanded across a wide range of chemistry fields, including diverse organic compounds and active pharmaceutical ingredients, coordination compounds, organometallic complexes, main group frameworks, and technologically relevant materials. This Review aims to highlight recent advancements and accomplishments in mechanochemistry, underscoring its potential as a viable and eco-friendly alternative to conventional solution-based methods in the field of synthetic chemistry.","PeriodicalId":29797,"journal":{"name":"ACS Organic & Inorganic Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141947619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-02DOI: 10.1021/acsorginorgau.4c00039
Paloma Mingueza-Verdejo, Susi Hervàs-Arnandis, Judit Oliver-Meseguer, Antonio Leyva-Pérez
The synthesis of alkyl halides can be performed by simply halide exchange reactions between two different alkyl halides, catalyzed by aluminosilicates. Here, we show that commercially available alumina shows a superior catalytic activity for the halogen exchange reaction between long alkyl halides (more than 6 carbons), including fluorides, in either batch or flow modes. The catalytic activity of the solid alumina is modulated by alkaline countercations on the surface, and sodium-supported alumina shows the optimal performance for the iodo-bromo and iodo-fluoro exchange under inflow reaction conditions, after >24 h reaction time, without any external additive.
{"title":"Additive-Free Commercial Alumina Catalyzes the Halogen Exchange Reaction of Long Alkyl Halides in Batch and in Flow Processes","authors":"Paloma Mingueza-Verdejo, Susi Hervàs-Arnandis, Judit Oliver-Meseguer, Antonio Leyva-Pérez","doi":"10.1021/acsorginorgau.4c00039","DOIUrl":"https://doi.org/10.1021/acsorginorgau.4c00039","url":null,"abstract":"The synthesis of alkyl halides can be performed by simply halide exchange reactions between two different alkyl halides, catalyzed by aluminosilicates. Here, we show that commercially available alumina shows a superior catalytic activity for the halogen exchange reaction between long alkyl halides (more than 6 carbons), including fluorides, in either batch or flow modes. The catalytic activity of the solid alumina is modulated by alkaline countercations on the surface, and sodium-supported alumina shows the optimal performance for the iodo-bromo and iodo-fluoro exchange under inflow reaction conditions, after >24 h reaction time, without any external additive.","PeriodicalId":29797,"journal":{"name":"ACS Organic & Inorganic Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141884143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-17DOI: 10.1021/acsorginorgau.4c00031
Jenny Y. Yang, Ryan P. King
Bipyridines and azaarenes are an important class of ligands that impart unique and tunable properties to transition metal complexes and catalysts. While some derivatives are commercially available, noncommercial analogues are often challenging to prepare and purify. Herein, we report a general nucleophilic aromatic substitution reaction that converts cationic trimethylaminated bipyridines into a series of functionalized bipyridines. Our method showcases a series of C–O, C–S, and C–F bond-forming reactions as well as a selective monodemethylation that converts the electron-deficient trimethylammonium to an electron-rich dimethylamine. The approach was further applied to diversification of pharmaceuticals and natural products and was applied to the total synthesis of Graveolinine and the preparation of Graveolinine derivatives.
{"title":"Diversification of Bipyridines and Azaheterocycles via Nucleophilic Displacement of Trimethylammoniums","authors":"Jenny Y. Yang, Ryan P. King","doi":"10.1021/acsorginorgau.4c00031","DOIUrl":"https://doi.org/10.1021/acsorginorgau.4c00031","url":null,"abstract":"Bipyridines and azaarenes are an important class of ligands that impart unique and tunable properties to transition metal complexes and catalysts. While some derivatives are commercially available, noncommercial analogues are often challenging to prepare and purify. Herein, we report a general nucleophilic aromatic substitution reaction that converts cationic trimethylaminated bipyridines into a series of functionalized bipyridines. Our method showcases a series of C–O, C–S, and C–F bond-forming reactions as well as a selective monodemethylation that converts the electron-deficient trimethylammonium to an electron-rich dimethylamine. The approach was further applied to diversification of pharmaceuticals and natural products and was applied to the total synthesis of Graveolinine and the preparation of Graveolinine derivatives.","PeriodicalId":29797,"journal":{"name":"ACS Organic & Inorganic Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141719749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-21DOI: 10.1021/acsorginorgau.4c00025
Zhining Xu, Ervin Kovács
The electrochemical oxidation of amines to nitriles and imines represents a critical frontier in organic electrochemistry, offering a sustainable pathway to these valuable compounds. Nitriles and amines are pivotal in various industrial applications, including pharmaceuticals, agrochemicals, and materials science. This review encapsulates the recent advancements in the electrooxidation process, emphasizing mechanistic understanding, electrode material innovations, optimization of reaction conditions, and exploration of solvent and electrolyte systems. Additionally, the review addresses the operational parameters that significantly affect the electrooxidation process, such as current density, temperature, and electrode surface, offering insights into their optimization for enhanced performance. By providing a comprehensive view of the current state and prospects of amine electrooxidation to nitriles and imines, this review aims to inspire further development, innovation, and research in this promising area of green chemistry.
{"title":"Beyond Traditional Synthesis: Electrochemical Approaches to Amine Oxidation for Nitriles and Imines","authors":"Zhining Xu, Ervin Kovács","doi":"10.1021/acsorginorgau.4c00025","DOIUrl":"https://doi.org/10.1021/acsorginorgau.4c00025","url":null,"abstract":"The electrochemical oxidation of amines to nitriles and imines represents a critical frontier in organic electrochemistry, offering a sustainable pathway to these valuable compounds. Nitriles and amines are pivotal in various industrial applications, including pharmaceuticals, agrochemicals, and materials science. This review encapsulates the recent advancements in the electrooxidation process, emphasizing mechanistic understanding, electrode material innovations, optimization of reaction conditions, and exploration of solvent and electrolyte systems. Additionally, the review addresses the operational parameters that significantly affect the electrooxidation process, such as current density, temperature, and electrode surface, offering insights into their optimization for enhanced performance. By providing a comprehensive view of the current state and prospects of amine electrooxidation to nitriles and imines, this review aims to inspire further development, innovation, and research in this promising area of green chemistry.","PeriodicalId":29797,"journal":{"name":"ACS Organic & Inorganic Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-19DOI: 10.1021/acsorginorgau.4c00027
Luca Giovanelli, Younal Ksari, Hela Mrezguia, Eric Salomon, Marco Minissale, Abraham B. Alemayehu, Abhik Ghosh
A combined direct and inverse photoemission study of coinage metal corroles suggests that the latter technique, in favorable cases, can provide some additional information relative to electrochemical measurements. Thus, whereas inverse photoemission spectroscopy (IPES) provides relative electron affinities for electron addition to different unoccupied orbitals, electrochemical reduction potentials shed light on the energetics of successive electron additions. While all three coinage metal triphenylcorrole (TPC) complexes exhibit similar ionization potentials, they exhibit dramatically different inverse photoemission spectra. For Cu[TPC], the lowest-energy IPES feature (0.74 eV) is found to be exceedingly close to the Fermi level; it is significantly higher for Ag[TPC] (1.65 eV) and much higher for Au[TPC] (2.40 eV). These differences qualitatively mirror those observed for electrochemical reduction potentials and are related to a partially metal-centered LUMO in the case of Cu- and Ag[TPC] and a fully corrole-based LUMO in the case of Au[TPC]; the latter orbital corresponds to the LUMO+1 in the case of Ag[TPC].
{"title":"Inverse Photoemission Spectroscopy of Coinage Metal Corroles: Comparison with Solution-Phase Electrochemistry","authors":"Luca Giovanelli, Younal Ksari, Hela Mrezguia, Eric Salomon, Marco Minissale, Abraham B. Alemayehu, Abhik Ghosh","doi":"10.1021/acsorginorgau.4c00027","DOIUrl":"https://doi.org/10.1021/acsorginorgau.4c00027","url":null,"abstract":"A combined direct and inverse photoemission study of coinage metal corroles suggests that the latter technique, in favorable cases, can provide some additional information relative to electrochemical measurements. Thus, whereas inverse photoemission spectroscopy (IPES) provides relative electron affinities for electron addition to different unoccupied orbitals, electrochemical reduction potentials shed light on the energetics of <i>successive</i> electron additions. While all three coinage metal triphenylcorrole (TPC) complexes exhibit similar ionization potentials, they exhibit dramatically different inverse photoemission spectra. For Cu[TPC], the lowest-energy IPES feature (0.74 eV) is found to be exceedingly close to the Fermi level; it is significantly higher for Ag[TPC] (1.65 eV) and much higher for Au[TPC] (2.40 eV). These differences qualitatively mirror those observed for electrochemical reduction potentials and are related to a partially metal-centered LUMO in the case of Cu- and Ag[TPC] and a fully corrole-based LUMO in the case of Au[TPC]; the latter orbital corresponds to the LUMO+1 in the case of Ag[TPC].","PeriodicalId":29797,"journal":{"name":"ACS Organic & Inorganic Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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