51
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Nutting JE, Gerken JB, Stamoulis AG, Bruns DL, Stahl SS. "How Should I Think about Voltage? What Is Overpotential?": Establishing an Organic Chemistry Intuition for Electrochemistry. J Org Chem 2021; 86:15875-15885. [PMID: 34609137 DOI: 10.1021/acs.joc.1c01520] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Redox reactions are ubiquitous in organic synthesis and intrinsic to organic electrosynthesis. The language and concepts used to describe reactions in these domains are sufficiently different to create barriers that hinder broader adoption and understanding of electrochemical methods. To bridge these gaps, this Synopsis compares chemical and electrochemical redox reactions, including concepts of free energy, voltage, kinetic barriers, and overpotential. This discussion is intended to increase the accessibility of electrochemistry for organic chemists lacking formal training in this area.
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Affiliation(s)
- Jordan E Nutting
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - James B Gerken
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Alexios G Stamoulis
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - David L Bruns
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Shannon S Stahl
- Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
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52
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Deng Y, Yang T, Wang H, Yang C, Cheng L, Yin SF, Kambe N, Qiu R. Recent Progress on Photocatalytic Synthesis of Ester Derivatives and Reaction Mechanisms. Top Curr Chem (Cham) 2021; 379:42. [PMID: 34668085 DOI: 10.1007/s41061-021-00355-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 10/05/2021] [Indexed: 11/28/2022]
Abstract
Esters and their derivatives are distributed widely in natural products, pharmaceuticals, fine chemicals and other fields. Esters are important building blocks in pharmaceuticals such as clopidogrel, methylphenidate, fenofibrate, travoprost, prasugrel, oseltamivir, eszopiclone and fluticasone. Therefore, esterification reaction becomes more and more popular in the photochemical field. In this review, we highlight three types of reactions to synthesize esters using photochemical strategies. The reaction mechanisms involve mainly single electron transfer, energy transfer or other radical procedures.
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Affiliation(s)
- Yiqiang Deng
- College of Chemical Engineering, Key Laboratory of Inferior Crude Oil Upgrade Processing of Guangdong Provincial Higher Education Institutes, Guangdong University of Petrochemical Technology, Maoming, 525000, Guangdong, China.
| | - Tianbao Yang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Hui Wang
- College of Chemical Engineering, Key Laboratory of Inferior Crude Oil Upgrade Processing of Guangdong Provincial Higher Education Institutes, Guangdong University of Petrochemical Technology, Maoming, 525000, Guangdong, China
| | - Chong Yang
- College of Chemical Engineering, Key Laboratory of Inferior Crude Oil Upgrade Processing of Guangdong Provincial Higher Education Institutes, Guangdong University of Petrochemical Technology, Maoming, 525000, Guangdong, China
| | - Lihua Cheng
- College of Chemical Engineering, Key Laboratory of Inferior Crude Oil Upgrade Processing of Guangdong Provincial Higher Education Institutes, Guangdong University of Petrochemical Technology, Maoming, 525000, Guangdong, China
| | - Shuang-Feng Yin
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Nobuaki Kambe
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan
| | - Renhua Qiu
- College of Chemical Engineering, Key Laboratory of Inferior Crude Oil Upgrade Processing of Guangdong Provincial Higher Education Institutes, Guangdong University of Petrochemical Technology, Maoming, 525000, Guangdong, China. .,State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China.
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53
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Shi S, Salahi F, Vibbert HB, Rahman M, Snyder SA, Norton JR. Generation of α‐Boryl Radicals by H
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Transfer and their Use in Cycloisomerizations. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Shicheng Shi
- Department of Chemistry Columbia University 3000 Broadway New York NY 10027 USA
| | - Farbod Salahi
- Department of Chemistry University of Chicago 5735 South Ellis Avenue Chicago IL 60637 USA
| | - Hunter B. Vibbert
- Department of Chemistry Columbia University 3000 Broadway New York NY 10027 USA
| | - Maleeha Rahman
- Department of Chemistry Barnard College 3009 Broadway New York NY 10027 USA
| | - Scott A. Snyder
- Department of Chemistry University of Chicago 5735 South Ellis Avenue Chicago IL 60637 USA
| | - Jack R. Norton
- Department of Chemistry Columbia University 3000 Broadway New York NY 10027 USA
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54
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Shi S, Salahi F, Vibbert HB, Rahman M, Snyder SA, Norton JR. Generation of α-Boryl Radicals by H . Transfer and their Use in Cycloisomerizations. Angew Chem Int Ed Engl 2021; 60:22678-22682. [PMID: 34405506 PMCID: PMC8582025 DOI: 10.1002/anie.202107665] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Indexed: 02/03/2023]
Abstract
Carbon-centered radicals can be stabilized by delocalization of their spin density into the vacant p orbital of a boron substituent. α-Vinyl boronates, in particular pinacol (Bpin) derivatives, are excellent hydrogen atom acceptors. Under H2 , in the presence of a cobaloxime catalyst, they generate α-boryl radicals; these species can undergo 5-exo radical cyclizations if appropriate double bond acceptors are present, leading to densely functionalized heterocycles with tertiary substituents on Bpin. The reaction shows good functional group tolerance with wide scope, and the resulting boronate products can be converted into other useful functionalities.
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Affiliation(s)
- Shicheng Shi
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027
| | - Farbod Salahi
- Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637
| | - Hunter B. Vibbert
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027
| | - Maleeha Rahman
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027
| | - Scott A. Snyder
- Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637
| | - Jack R. Norton
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027
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55
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Fertig AA, Brennessel WW, McKone JR, Matson EM. Concerted Multiproton-Multielectron Transfer for the Reduction of O 2 to H 2O with a Polyoxovanadate Cluster. J Am Chem Soc 2021; 143:15756-15768. [PMID: 34528799 DOI: 10.1021/jacs.1c07076] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The concerted transfer of protons and electrons enables the activation of small-molecule substrates by bypassing energetically costly intermediates. Here, we present the synthesis and characterization of several hydrogenated forms of an organofunctionalized vanadium oxide assembly, [V6O13(TRIOLNO2)2]2-, and their ability to facilitate the concerted transfer of protons and electrons to O2. Electrochemical analysis reveals that the fully reduced cluster is capable of mediating 2e-/2H+ transfer reactions from surface hydroxide ligands, with an average bond dissociation free energy (BDFE) of 61.6 kcal/mol. Complementary stoichiometric experiments with hydrogen-atom-accepting reagents of established bond strengths confirm that the electrochemically established BDFE predicts the 2H+/2e- transfer reactivity of the assembly. Finally, the reactivity of the reduced polyoxovanadate toward O2 reduction is summarized; our results indicate a stepwise reduction of the substrate, proceeding through H2O2 en route to the formation of H2O. Kinetic isotope effect experiments confirm the participation of hydrogen transfer in the rate-determining step of both the reduction of O2 and H2O2. This work constitutes the first example of hydrogen atom transfer for small-molecule activation with reduced polyoxometalates, where both electron and proton originate from the cluster.
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Affiliation(s)
- Alex A Fertig
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - William W Brennessel
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - James R McKone
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Ellen M Matson
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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56
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Dobbelaar E, Rauber C, Bonck T, Kelm H, Schmitz M, de Waal Malefijt ME, Klein JEMN, Krüger HJ. Combining Structural with Functional Model Properties in Iron Synthetic Analogue Complexes for the Active Site in Rabbit Lipoxygenase. J Am Chem Soc 2021; 143:13145-13155. [PMID: 34383499 DOI: 10.1021/jacs.1c04422] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Iron complexes that model the structural and functional properties of the active iron site in rabbit lipoxygenase are described. The ligand sphere of the mononuclear pseudo-octahedral cis-(carboxylato)(hydroxo)iron(III) complex, which is completed by a tetraazamacrocyclic ligand, reproduces the first coordination shell of the active site in the enzyme. In addition, two corresponding iron(II) complexes are presented that differ in the coordination of a water molecule. In their structural and electronic properties, both the (hydroxo)iron(III) and the (aqua)iron(II) complex reflect well the only two essential states found in the enzymatic mechanism of peroxidation of polyunsaturated fatty acids. Furthermore, the ferric complex is shown to undergo hydrogen atom abstraction reactions with O-H and C-H bonds of suitable substrates, and the bond dissociation free energy of the coordinated water ligand of the ferrous complex is determined to be 72.4 kcal·mol-1. Theoretical investigations of the reactivity support a concerted proton-coupled electron transfer mechanism in close analogy to the initial step in the enzymatic mechanism. The propensity of the (hydroxo)iron(III) complex to undergo H atom abstraction reactions is the basis for its catalytic function in the aerobic peroxidation of 2,4,6-tri(tert-butyl)phenol and its role as a radical initiator in the reaction of dihydroanthracene with oxygen.
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Affiliation(s)
- Emiel Dobbelaar
- Department of Chemistry, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Christian Rauber
- Department of Chemistry, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Thorsten Bonck
- Department of Chemistry, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Harald Kelm
- Department of Chemistry, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Markus Schmitz
- Department of Chemistry, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Matina Eloïse de Waal Malefijt
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 9, 9747 AG Groningen, The Netherlands
| | - Johannes E M N Klein
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 9, 9747 AG Groningen, The Netherlands
| | - Hans-Jörg Krüger
- Department of Chemistry, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
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57
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Determining the Overpotential of Electrochemical Fuel Synthesis Mediated by Molecular Catalysts: Recommended Practices, Standard Reduction Potentials, and Challenges. ChemElectroChem 2021. [DOI: 10.1002/celc.202100576] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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58
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Amtawong J, Skjelstad BB, Handford RC, Suslick BA, Balcells D, Tilley TD. C-H Activation by RuCo 3O 4 Oxo Cubanes: Effects of Oxyl Radical Character and Metal-Metal Cooperativity. J Am Chem Soc 2021; 143:12108-12119. [PMID: 34318666 DOI: 10.1021/jacs.1c04069] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
High-valent multimetallic-oxo/oxyl species have been implicated as intermediates in oxidative catalysis involving proton-coupled electron transfer (PCET) reactions, but the reactive nature of these oxo species has hindered the development of an in-depth understanding of their mechanisms and multimetallic character. The mechanism of C-H oxidation by previously reported RuCo3O4 cubane complexes bearing a terminal RuV-oxo ligand, with significant oxyl radical character, was investigated. The rate-determining step involves H atom abstraction (HAA) from an organic substrate to generate a Ru-OH species and a carbon-centered radical. Radical intermediates are subsequently trapped by another equivalent of the terminal oxo to afford isolable radical-trapped cubane complexes. Density functional theory (DFT) reveals a barrierless radical combination step that is more favorable than an oxygen-rebound mechanism by 12.3 kcal mol-1. This HAA reactivity to generate organic products is influenced by steric congestion and the C-H bond dissociation energy of the substrate. Tuning the electronic properties of the cubane (i.e., spin density localized on terminal oxo, basicity, and redox potential) by varying the donor ability of ligands at the Co sites modulates C-H activations by the RuV-oxo fragment and enables construction of structure-activity relationships. These results reveal a mechanistic pathway for C-H activation by high-valent metal-oxo species with oxyl radical character and provide insights into cooperative effects of multimetallic centers in tuning PCET reactivity.
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Affiliation(s)
- Jaruwan Amtawong
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Bastian Bjerkem Skjelstad
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
| | - Rex C Handford
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, United States
| | - Benjamin A Suslick
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - David Balcells
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
| | - T Don Tilley
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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59
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Schneck F, Finger M, Siewert I, Schneider S. Solvent dependent C−H Bond Strength in a Nickel Pincer Complex. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202100077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Felix Schneck
- Universität Göttingen Institut für Anorganische Chemie Tammannstraße 4 37077 Göttingen Germany
| | - Markus Finger
- Universität Göttingen Institut für Anorganische Chemie Tammannstraße 4 37077 Göttingen Germany
| | - Inke Siewert
- Universität Göttingen Institut für Anorganische Chemie Tammannstraße 4 37077 Göttingen Germany
| | - Sven Schneider
- Universität Göttingen Institut für Anorganische Chemie Tammannstraße 4 37077 Göttingen Germany
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60
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Brinkmeier A, Schulz RA, Buchhorn M, Spyra CJ, Dechert S, Demeshko S, Krewald V, Meyer F. Structurally Characterized μ-1,2-Peroxo/Superoxo Dicopper(II) Pair. J Am Chem Soc 2021; 143:10361-10366. [PMID: 34191490 DOI: 10.1021/jacs.1c04316] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Superoxo complexes of copper are primary adducts in several O2-activating Cu-containing metalloenzymes as well as in other Cu-mediated oxidation and oxygenation reactions. Because of their intrinsically high reactivity, however, isolation of Cux(O2•-) species is challenging. Recent work (J. Am. Chem. Soc. 2017, 139, 9831; 2019, 141, 12682) established fundamental thermochemical data for the H atom abstraction reactivity of dicopper(II) superoxo complexes, but structural characterization of these important intermediates was so far lacking. Here we report the first crystallographic structure determination of a superoxo dicopper(II) species (3) together with the structure of its 1e- reduced peroxo congener (2; a rare cis-μ-1,2-peroxo dicopper(II) complex). Interconversion of 2 and 3 occurs at low potential (-0.58 V vs Fc/Fc+) and is reversible both chemically and electrochemically. Comparison of metric parameters (d(O-O) = 1.441(2) Å for 2 vs 1.329(7) Å for 3) and of spectroscopic signatures (ν̃(16O-16O) = 793 cm-1 for 2 vs 1073 cm-1 for 3) reflects that the redox process occurs at the bridging O2-derived unit. The CuII-O2•--CuII complex has an S = 1/2 spin ground state according to magnetic and EPR data, in agreement with density functional theory calculations. Computations further show that the potential associated with changes of the Cu-O-O-Cu dihedral angle is shallow for both 2 and 3. These findings provide a structural basis for the low reorganization energy of the kinetically facile 1e- interconversion of μ-1,2-superoxo/peroxo dicopper(II) couples, and they open the door for comprehensive studies of these key intermediates in Cux/O2 chemistry.
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Affiliation(s)
- Alexander Brinkmeier
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Roland A Schulz
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Moritz Buchhorn
- Fachbereich Chemie, Theoretische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 4, D-64287 Darmstadt, Germany
| | - Can-Jerome Spyra
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Sebastian Dechert
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Serhiy Demeshko
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Vera Krewald
- Fachbereich Chemie, Theoretische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 4, D-64287 Darmstadt, Germany
| | - Franc Meyer
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany.,International Center for Advanced Studies of Energy Conversion (ICASEC), Universität Göttingen, Tammannstraße 6, D-37077 Göttingen, Germany
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61
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Crossland PM, Guo Y, Que L. Spontaneous Formation of an Fe/Mn Diamond Core: Models for the Fe/Mn Sites in Class 1c Ribonucleotide Reductases. Inorg Chem 2021; 60:8710-8721. [PMID: 34110143 DOI: 10.1021/acs.inorgchem.1c00684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A handful of oxygen-activating enzymes has recently been found to contain Fe/Mn active sites, like Class 1c ribonucleotide reductases and R2-like ligand-binding oxidase, which are closely related to their better characterized diiron cousins. These enzymes are proposed to form high-valent intermediates with Fe-O-Mn cores. Herein, we report the first examples of synthetic Fe/Mn complexes that mimic doubly bridged intermediates proposed for enzymatic oxygen activation. Fe K-edge extended X-ray absorption fine structure (EXAFS) analysis has been used to characterize the structures of each of these compounds. Linear compounds accurately model the Fe···Mn distances found in Fe/Mn proteins in their resting states, and doubly bridged diamond core compounds accurately model the distances found in high-valent biological intermediates. Unlike their diiron analogues, the paramagnetic nature of Fe/Mn compounds can be analyzed by EPR, revealing S = 1/2 signals that reflect antiferromagnetic coupling between the high-spin Fe(III) and Mn(III) units of heterobimetallic centers. These compounds undergo electron transfer with various ferrocenes, linear compounds being capable of oxidizing diacetyl ferrocene, a weak reductant, and diamond core compounds being capable of oxidizing acetyl ferrocene. Diamond core compounds can also perform HAT reactions from substrates with X-H bonds with bond dissociation free energies (BDFEs) up to 75 kcal/mol and are capable of oxidizing TEMPO-H at rates of 0.32-0.37 M-1 s-1, which are comparable to those reported for some mononuclear FeIII-OH and MnIII-OH compounds. However, such reactivity is not observed for the corresponding diiron compounds, a difference that Nature may have taken advantage of in evolving enzymes with heterobimetallic active sites.
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Affiliation(s)
- Patrick M Crossland
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
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62
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Sarkar S, Maitra A, Lake WR, Warburton RE, Hammes-Schiffer S, Dawlaty JM. Mechanistic Insights about Electrochemical Proton-Coupled Electron Transfer Derived from a Vibrational Probe. J Am Chem Soc 2021; 143:8381-8390. [PMID: 34042429 DOI: 10.1021/jacs.1c01977] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Proton-coupled electron transfer (PCET) is a fundamental step in a wide range of electrochemical processes, including those of interest in energy conversion and storage. Despite its importance, several mechanistic details of such reactions remain unclear. Here, we have combined a proton donor (tertiary ammonium) with a vibrational Stark-shift probe (benzonitrile), to track the process from the entry of the reactants into the electrical double layer (EDL), to the PCET reaction associated with proton donation to the electrode, and the formation of products. We have used operando vibrational spectroscopy and periodic density functional theory under electrochemical bias to assign the reactant and product peaks and their Stark shifts. We have identified three main stages for the progress of the PCET reaction as a function of applied potential. First, we have determined the potential necessary for desolvation of the reactants and their entry into the polarizing environment of the EDL. Second, we have observed the appearance of product peaks prior to the onset of steady state electrochemical current, indicating formation of a stationary population of products that does not turn over. Finally, more negative of the onset potential, the electrode attracts additional reactants, displacing the stationary products and enabling steady state current. This work shows that the integration of a vibrational Stark-shift probe with a proton donor provides critical insight into the interplay between interfacial electrostatics and heterogeneous chemical reactions. Such insights cannot be obtained from electrochemical measurements alone.
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Affiliation(s)
- Sohini Sarkar
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Anwesha Maitra
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - William R Lake
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Robert E Warburton
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Sharon Hammes-Schiffer
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Jahan M Dawlaty
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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63
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Forrest SJK, Schluschaß B, Yuzik-Klimova EY, Schneider S. Nitrogen Fixation via Splitting into Nitrido Complexes. Chem Rev 2021; 121:6522-6587. [DOI: 10.1021/acs.chemrev.0c00958] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sebastian J. K. Forrest
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Bastian Schluschaß
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | | | - Sven Schneider
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
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64
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Hua SA, Paul LA, Oelschlegel M, Dechert S, Meyer F, Siewert I. A Bioinspired Disulfide/Dithiol Redox Switch in a Rhenium Complex as Proton, H Atom, and Hydride Transfer Reagent. J Am Chem Soc 2021; 143:6238-6247. [PMID: 33861085 DOI: 10.1021/jacs.1c01763] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The transfer of multiple electrons and protons is of crucial importance in many reactions relevant in biology and chemistry. Natural redox-active cofactors are capable of storing and releasing electrons and protons under relatively mild conditions and thus serve as blueprints for synthetic proton-coupled electron transfer (PCET) reagents. Inspired by the prominence of the 2e-/2H+ disulfide/dithiol couple in biology, we investigate herein the diverse PCET reactivity of a Re complex equipped with a bipyridine ligand featuring a unique SH···-S moiety in the backbone. The disulfide bond in fac-[Re(S-Sbpy)(CO)3Cl] (1, S-Sbpy = [1,2]dithiino[4,3-b:5,6-b']dipyridine) undergoes two successive reductions at equal potentials of -1.16 V vs Fc+|0 at room temperature forming [Re(S2bpy)(CO)3Cl]2- (12-, S2bpy = [2,2'-bipyridine]-3,3'-bis(thiolate)). 12- has two adjacent thiolate functions at the bpy periphery, which can be protonated forming the S-H···-S unit, 1H-. The disulfide/dithiol switch exhibits a rich PCET reactivity and can release a proton (ΔG°H+ = 34 kcal mol-1, pKa = 24.7), an H atom (ΔG°H• = 59 kcal mol-1), or a hydride ion (ΔG°H- = 60 kcal mol-1) as demonstrated in the reactivity with various organic test substrates.
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Affiliation(s)
- Shao-An Hua
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Lucas A Paul
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Manuel Oelschlegel
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Sebastian Dechert
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstraße 4, D-37077 Göttingen, Germany
| | - Franc Meyer
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstraße 4, D-37077 Göttingen, Germany.,Universität Göttingen, International Center for Advanced Studies of Energy Conversion (ICASEC), Tammannstraße 6, D-37077 Göttingen, Germany
| | - Inke Siewert
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstraße 4, D-37077 Göttingen, Germany.,Universität Göttingen, International Center for Advanced Studies of Energy Conversion (ICASEC), Tammannstraße 6, D-37077 Göttingen, Germany
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65
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Zhang L, Xu T, Ji W, Wang X, Cheng S, Zhang S, Zhang Y, Zhang M. Ag 2S/Ag Nanoparticle Microelectrodes for In Vivo Potentiometric Measurement of Hydrogen Sulfide Dynamics in the Rat Brain. Anal Chem 2021; 93:7063-7070. [PMID: 33900732 DOI: 10.1021/acs.analchem.1c00540] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Hydrogen sulfide (H2S) plays a pivotal role in gas signal transduction, neuroprotection, and regulation of physiological and pathological processes. However, in vivo tracking the dynamic of hydrogen sulfide in the complex brain environment still faces huge challenges. This study demonstrates a new potentiometric method to monitor in vivo the dynamics of hydrogen sulfide in the rat brain using silver nanoparticles (AgNPs)-modified carbon fiber microelectrodes (AgNPs/CFE) pretreated with Na2S (i.e., Ag2S/AgNPs/CFE), which acts as a solid-contact and ion-selective microelectrode. The Ag2S/AgNPs/CFE exhibits good potential response toward hydrogen sulfide in the range of 2.5-160 μM, with a detection limit of 0.8 μM. Because of the presence of Ag2S, the Ag2S/AgNPs/CFE shows good selectivity to hydrogen sulfide, avoiding the interference from coexistent electroactive neurochemicals and the analogies, such as ascorbic acid and cysteine in the central nervous system. This good selectivity combined with the reversibility, protein antifouling, and biocompatibility of the microelectrode enables the Ag2S/AgNPs/CFE to detect hydrogen sulfide in the rat brain during local microinfusion of Na2S and the change in pH. Our study provides a reliable method to track hydrogen sulfide selectively in vivo, which will help to explore the function of hydrogen sulfide in neurophysiology and pathology.
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Affiliation(s)
- Li Zhang
- Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Tianci Xu
- Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Wenliang Ji
- Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Xiaofang Wang
- Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Shuwen Cheng
- Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Shuai Zhang
- Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Yue Zhang
- Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Meining Zhang
- Department of Chemistry, Renmin University of China, Beijing 100872, China
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66
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Tanabe Y, Nishibayashi Y. Comprehensive insights into synthetic nitrogen fixation assisted by molecular catalysts under ambient or mild conditions. Chem Soc Rev 2021; 50:5201-5242. [PMID: 33651046 DOI: 10.1039/d0cs01341b] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
N2 is fixed as NH3 industrially by the Haber-Bosch process under harsh conditions, whereas biological nitrogen fixation is achieved under ambient conditions, which has prompted development of alternative methods to fix N2 catalyzed by transition metal molecular complexes. Since the early 21st century, catalytic conversion of N2 into NH3 under ambient conditions has been achieved by using molecular catalysts, and now H2O has been utilized as a proton source with turnover frequencies reaching the values found for biological nitrogen fixation. In this review, recent advances in the development of molecular catalysts for synthetic N2 fixation under ambient or mild conditions are summarized, and potential directions for future research are also discussed.
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Affiliation(s)
- Yoshiaki Tanabe
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Yoshiaki Nishibayashi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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67
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Zhang R, Zhou W, Warren JJ. Photo-initiated oxidation of C-H bonds by diimine complexes of vanadium(V). Chem Commun (Camb) 2021; 57:4007-4010. [PMID: 33885690 DOI: 10.1039/d1cc00649e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The photochemical activation of carbon-hydrogen bonds by vanadium(v)-dioxo and vanadium(v)-oxo-peroxo diimine complexes is described. Reactions were carried out using a selection of organic substrates with C-H bond dissociation free energy values between 70 and 97 kcal mol-1. The ability to activate C-H bonds using vanadium(v)-dioxo and vanadium(v)-oxo-peroxo diimine complexes varies with different bond dissociation free energy. Compounds with weaker C-H bonds are oxidized in minutes, rather than in days for thermal oxidations by the corresponding complexes. Dioxygen is necessary for substrate consumption, which suggests that the electronically excited V complexes are radical reaction initiators via H-atom abstraction from the organic substrate.
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Affiliation(s)
- Rui Zhang
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby BC V5A 1S6, Canada.
| | - Wen Zhou
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby BC V5A 1S6, Canada.
| | - Jeffrey J Warren
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby BC V5A 1S6, Canada.
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68
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Kim H, Rogler PJ, Sharma SK, Schaefer AW, Solomon EI, Karlin KD. Ferric Heme Superoxide Reductive Transformations to Ferric Heme (Hydro)Peroxide Species: Spectroscopic Characterization and Thermodynamic Implications for H‐Atom Transfer (HAT). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202013791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hyun Kim
- Chemistry Department Johns Hopkins University Baltimore MD 21218 USA
| | - Patrick J. Rogler
- Chemistry Department Johns Hopkins University Baltimore MD 21218 USA
| | - Savita K. Sharma
- Chemistry Department Johns Hopkins University Baltimore MD 21218 USA
| | | | | | - Kenneth D. Karlin
- Chemistry Department Johns Hopkins University Baltimore MD 21218 USA
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69
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Kim H, Rogler PJ, Sharma SK, Schaefer AW, Solomon EI, Karlin KD. Ferric Heme Superoxide Reductive Transformations to Ferric Heme (Hydro)Peroxide Species: Spectroscopic Characterization and Thermodynamic Implications for H-Atom Transfer (HAT). Angew Chem Int Ed Engl 2021; 60:5907-5912. [PMID: 33348450 PMCID: PMC7920932 DOI: 10.1002/anie.202013791] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Indexed: 01/07/2023]
Abstract
A new end-on low-spin ferric heme peroxide, [(PIm )FeIII -(O22- )]- (PIm -P), and subsequently formed hydroperoxide species, [(PIm )FeIII -(OOH)] (PIm -HP) are generated utilizing the iron-porphyrinate PIm with its tethered axial base imidazolyl group. Measured thermodynamic parameters, the ferric heme superoxide [(PIm )FeIII -(O2⋅- )] (PIm -S) reduction potential (E°') and the PIm -HP pKa value, lead to the finding of the OO-H bond-dissociation free energy (BDFE) of PIm -HP as 69.5 kcal mol-1 using a thermodynamic square scheme and Bordwell relationship. The results are validated by the observed oxidizing ability of PIm -S via hydrogen-atom transfer (HAT) compared to that of the F8 superoxide complex, [(F8 )FeIII -(O2.- )] (S) (F8 =tetrakis(2,6-difluorophenyl)porphyrinate, without an internally appended axial base imidazolyl), as determined from reactivity comparison of superoxide complexes PIm -S and S with the hydroxylamine (O-H) substrates TEMPO-H and ABNO-H.
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Affiliation(s)
- Hyun Kim
- Chemistry Department, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Patrick J Rogler
- Chemistry Department, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Savita K Sharma
- Chemistry Department, Johns Hopkins University, Baltimore, MD, 21218, USA
| | | | - Edward I Solomon
- Chemistry Department, Stanford University, Stanford, CA, 94305, USA
| | - Kenneth D Karlin
- Chemistry Department, Johns Hopkins University, Baltimore, MD, 21218, USA
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70
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Agarwal RG, Kim HJ, Mayer JM. Nanoparticle O-H Bond Dissociation Free Energies from Equilibrium Measurements of Cerium Oxide Colloids. J Am Chem Soc 2021; 143:2896-2907. [PMID: 33565871 DOI: 10.1021/jacs.0c12799] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A novel equilibrium strategy for measuring the hydrogen atom affinity of colloidal metal oxide nanoparticles is presented. Reactions between oleate-capped cerium oxide nanoparticle colloids (nanoceria) and organic proton-coupled electron transfer (PCET) reagents are used as a model system. Nanoceria redox changes, or hydrogen loadings, and overall reaction stoichiometries were followed by both 1H NMR and X-ray absorption near-edge spectroscopies. These investigations revealed that, in many cases, reactions between nanoceria and PCET reagents reach equilibrium states with good mass balance. Each equilibrium state is a direct measure of the bond strength, or bond dissociation free energy (BDFE), between nanoceria and hydrogen. Further studies, including those with larger nanoceria, indicated that the relevant bond is a surface O-H. Thus, we have measured surface O-H BDFEs for nanoceria-the first experimental BDFEs for any nanoscale metal oxide. Remarkably, the measured CeO-H BDFEs span 13 kcal mol-1 (0.56 eV) with changes in the average redox state of the nanoceria colloid. Possible chemical models for this strong dependence are discussed. We propose that the tunability of ceria BDFEs may be important in explaining its effectiveness in catalysis. More generally, metal oxide BDFEs have been used as predictors of catalyst efficacy that, traditionally, have only been accessible by computational methods. These results provide important experimental benchmarks for metal oxide BDFEs and demonstrate that the concepts of molecular bond strength thermochemistry can be applied to nanoscale materials.
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Affiliation(s)
- Rishi G Agarwal
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Hyun-Jo Kim
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - James M Mayer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
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71
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Shada ADR, Miller AJM, Emge TJ, Goldman AS. Catalytic Dehydrogenation of Alkanes by PCP–Pincer Iridium Complexes Using Proton and Electron Acceptors. ACS Catal 2021. [DOI: 10.1021/acscatal.0c05160] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Arun Dixith Reddy Shada
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, United States
| | - Alexander J. M. Miller
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Thomas J. Emge
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, United States
| | - Alan S. Goldman
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, United States
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72
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Ashida Y, Nishibayashi Y. Catalytic conversion of nitrogen molecule into ammonia using molybdenum complexes under ambient reaction conditions. Chem Commun (Camb) 2021; 57:1176-1189. [PMID: 33443504 DOI: 10.1039/d0cc07146c] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nitrogen fixation using homogeneous transition metal complexes under mild reaction conditions is a challenging topic in the field of chemistry. Several successful examples of the catalytic conversion of nitrogen molecule into ammonia using various transition metal complexes in the presence of reductants and proton sources have been reported so far, together with detailed investigations on the reaction mechanism. Among these, only molybdenum complexes have been shown to serve as effective catalysts under ambient reaction conditions, in stark contrast with other transition metal-catalysed reactions that proceed at low reaction temperature such as -78 °C. In this feature article, we classify the molybdenum-catalysed reactions into four types: reactions via the Schrock cycle, reactions via dinuclear reaction systems, reactions via direct cleavage of the nitrogen-nitrogen triple bond of dinitrogen, and reactions via the Chatt-type cycle. We describe these catalytic systems focusing on the catalytic activity and mechanistic investigations. We hope that the present feature article provides useful information to develop more efficient nitrogen fixation systems under mild reaction conditions.
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Affiliation(s)
- Yuya Ashida
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Yoshiaki Nishibayashi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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73
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Vibbert HB, Neugebauer H, Norton JR, Hansen A, Bursch M, Grimme S. Hydrogen atom transfer rates from Tp-containing metal-hydrides to trityl radicals. CAN J CHEM 2021. [DOI: 10.1139/cjc-2020-0392] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The H• transfer rate constants for a series of group 6 molybdenum and tungsten pyrazolyl borate complexes are described. The rate constants for these complexes were found to span a range over 1 magnitude. Analysis of the H• transfer rate constants suggests that a combination of steric, electronic, and enthalpic factors are important in these reactions. Further analysis of the components suggests that the generated 17 e– radicals of these complexes are less electrophilic than the more commonly used CpCr(CO)3H complexes. General implications for H• transfer reactions are discussed.
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Affiliation(s)
- Hunter B. Vibbert
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - Hagen Neugebauer
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie der Universität Bonn, Beringstr. 4, Bonn, D-53115, Germany
| | - Jack R. Norton
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - Andreas Hansen
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie der Universität Bonn, Beringstr. 4, Bonn, D-53115, Germany
| | - Markus Bursch
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie der Universität Bonn, Beringstr. 4, Bonn, D-53115, Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie der Universität Bonn, Beringstr. 4, Bonn, D-53115, Germany
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74
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Bruns DL, Musaev DG, Stahl SS. Can Donor Ligands Make Pd(OAc) 2 a Stronger Oxidant? Access to Elusive Palladium(II) Reduction Potentials and Effects of Ancillary Ligands via Palladium(II)/Hydroquinone Redox Equilibria. J Am Chem Soc 2020; 142:19678-19688. [PMID: 33167610 DOI: 10.1021/jacs.0c09464] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Palladium(II)-catalyzed oxidation reactions represent an important class of methods for selective modification and functionalization of organic molecules. This field has benefitted greatly from the discovery of ancillary ligands that expand the scope, reactivity, and selectivity in these reactions; however, ancillary ligands also commonly poison these reactions. The different influences of ligands in these reactions remain poorly understood. For example, over the 60-year history of this field, the PdII/0 redox potentials for catalytically relevant Pd complexes have never been determined. Here, we report the unexpected discovery of (L)PdII(OAc)2-mediated oxidation of hydroquinones, the microscopic reverse of quinone-mediated oxidation of Pd0 commonly employed in PdII-catalyzed oxidation reactions. Analysis of redox equilibria arising from the reaction of (L)Pd(OAc)2 and hydroquinones (L = bathocuproine, 4,5-diazafluoren-9-one), generating reduced (L)Pd species and benzoquinones, provides the basis for determination of (L)PdII(OAc)2 reduction potentials. Experimental results are complemented by density functional theory calculations to show how a series of nitrogen-based ligands modulate the (L)PdII(OAc)2 reduction potential, thereby tuning the ability of PdII to serve as an effective oxidant of organic molecules in catalytic reactions.
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Affiliation(s)
- David L Bruns
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue Madison, Wisconsin 53706, United States
| | - Djamaladdin G Musaev
- Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Shannon S Stahl
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue Madison, Wisconsin 53706, United States
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75
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Li J, Zhu M, Han Y. Recent Advances in Electrochemical CO
2
Reduction on Indium‐Based Catalysts. ChemCatChem 2020. [DOI: 10.1002/cctc.202001350] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jiayu Li
- State Key Laboratory of Chemical Engineering School of Chemical Engineering East China University of Science and Technology Shanghai 200237 P.R. China
| | - Minghui Zhu
- State Key Laboratory of Chemical Engineering School of Chemical Engineering East China University of Science and Technology Shanghai 200237 P.R. China
| | - Yi‐Fan Han
- State Key Laboratory of Chemical Engineering School of Chemical Engineering East China University of Science and Technology Shanghai 200237 P.R. China
- Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education Zhengzhou University Zhengzhou 450001 P.R. China
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76
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Abstract
High-valent oxocobalt(IV) species have been invoked as key intermediates in oxidative catalysis, but investigations into the chemistry of proton-coupled redox reactions of such species have been limited. Herein, the reactivity of an established water oxidation catalyst, [Co4O4(OAc)4(py)4][PF6], toward H-atom abstraction reactions is described. Mechanistic analyses and density functional theory (DFT) calculations support a concerted proton-electron transfer (CPET) pathway in which the high energy intermediates formed in stepwise pathways are bypassed. Natural bond orbital (NBO) calculations point to cooperative donor-acceptor σ interactions at the transition state, whereby the H-atom of the substrate is transferred to an orbital delocalized over a Co3(μ3-O) fragment. The mechanistic insights provide design principles for the development of catalytic C-H activation processes mediated by a multimetallic oxo metal cluster.
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77
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Castillo-Lora J, Delley MF, Laga SM, Mayer JM. Two-Electron-Two-Proton Transfer from Colloidal ZnO and TiO 2 Nanoparticles to Molecular Substrates. J Phys Chem Lett 2020; 11:7687-7691. [PMID: 32838515 DOI: 10.1021/acs.jpclett.0c02359] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Transfers of multiple electrons and protons are challenging yet central to many energy-conversion processes and other chemical and biochemical reactions. Semiconducting oxides can hold multiple redox equivalents. This study describes the 2e-/2H+ transfer reactivity of photoreduced ZnO and TiO2 nanoparticle (NP) colloids with molecular 2e-/2H+ acceptors, to form new O-H, N-H, and C-H bonds. The reaction stoichiometries were monitored by NMR and optical spectroscopies. Faster 2e-/2H+ transfer rates were observed for substrates forming O-H or N-H bonds, presumably due to initial hydrogen bonding at the oxide surface. Chemically reduced ZnO NPs stabilized by Na+ or Ca2+ also engage in 2e-/2H+ transfer reactivity, showing that protons transferred in these processes are inherent to the oxide nanoparticles and do not exclusively stem from photoreduction. These results highlight the potential of ZnO and TiO2 for multiple proton-coupled electron transfer (PCET) reactions.
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Affiliation(s)
- Janelle Castillo-Lora
- Department of Chemistry, Yale University, 255 Prospect Street, New Haven, Connecticut 06520-8107, United States
| | - Murielle F Delley
- Department of Chemistry, Yale University, 255 Prospect Street, New Haven, Connecticut 06520-8107, United States
| | - Stephanie M Laga
- Department of Chemistry, Yale University, 255 Prospect Street, New Haven, Connecticut 06520-8107, United States
| | - James M Mayer
- Department of Chemistry, Yale University, 255 Prospect Street, New Haven, Connecticut 06520-8107, United States
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78
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VanNatta PE, Ramirez DA, Velarde AR, Ali G, Kieber-Emmons MT. Exceptionally High O–H Bond Dissociation Free Energy of a Dicopper(II) μ-Hydroxo Complex and Insights into the Geometric and Electronic Structure Origins Thereof. J Am Chem Soc 2020; 142:16292-16312. [DOI: 10.1021/jacs.0c06425] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Peter E. VanNatta
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - David A. Ramirez
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - Andres R. Velarde
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, United States
| | - Ghazanfar Ali
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, United States
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79
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Bezdek MJ, Pelczer I, Chirik PJ. Coordination-Induced N–H Bond Weakening in a Molybdenum Pyrrolidine Complex: Isotopic Labeling Provides Insight into the Pathway for H 2 Evolution. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00471] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Máté J. Bezdek
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - István Pelczer
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J. Chirik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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80
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Bruch QJ, Connor GP, McMillion ND, Goldman AS, Hasanayn F, Holland PL, Miller AJM. Considering Electrocatalytic Ammonia Synthesis via Bimetallic Dinitrogen Cleavage. ACS Catal 2020. [DOI: 10.1021/acscatal.0c02606] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Quinton J. Bruch
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Gannon P. Connor
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Noah D. McMillion
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Alan S. Goldman
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, United States
| | - Faraj Hasanayn
- Department of Chemistry, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Patrick L. Holland
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Alexander J. M. Miller
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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