1
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Patra K, Brennessel WW, Matson EM. Molecular Models of Atomically Dispersed Uranium at MoS 2 Surfaces Reveal Cooperative Mechanism of Water Reduction. J Am Chem Soc 2024; 146:20147-20157. [PMID: 38984489 PMCID: PMC11273346 DOI: 10.1021/jacs.4c05002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/26/2024] [Accepted: 06/26/2024] [Indexed: 07/11/2024]
Abstract
Single atoms of uranium supported on molybdenum sulfide surfaces (U@MoS2) have been recently demonstrated to facilitate the hydrogen evolution reaction (HER) through electrocatalysis. Theoretical calculations have predicted uranium hydroxide moieties bound to edge-sulfur atoms of MoS2 as a proposed transition state involved in the HER process. However, the isolation of relevant intermediates involved in this process remains a challenge, rendering mechanistic hypotheses unverified. The present work describes the isolation and characterization of a uranium-hydroxide intermediate on molybdenum sulfide surfaces using [(Cp*3Mo3S4)UCp*], a molecular model of a reduced uranium center supported at MoS2. Mechanistic investigations highlight the metalloligand cooperativity with uranium involved in the water activation pathway. The corresponding uranium-oxo analogue, [(Cp*3Mo3S4)Cp*U(═O)], was also accessed from the hydroxide cluster via hydrogen atom transfer and from [(Cp*3Mo3S4)UCp*] through an alternative direct oxygen atom transfer. These results provide an atomistic perspective on the reactivity of low-valent uranium at molybdenum sulfide surfaces toward water, modeling key intermediates associated with the HER of U@MoS2 catalysts.
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Affiliation(s)
- Kamaless Patra
- 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
| | - Ellen M. Matson
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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2
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Oloyede UN, Flowers RA. Coordination-induced bond weakening and small molecule activation by low-valent titanium complexes. Dalton Trans 2024; 53:2413-2441. [PMID: 38224159 DOI: 10.1039/d3dt03454b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Bond activation of small molecules through coordination to low valent metal complexes in M⋯X-H type interactions (where X = O, N, B, Si, etc.) leads to the formation of unusually weak X-H bonds and provides a powerful approach for the synthesis of target compounds under very mild conditions. Coordination of small molecules like water, amides, silanes, boranes, and dinitrogen to Ti(III) or Ti(II) complexes results in the synergetic redistribution of electrons between the metal orbitals and the ligand orbitals which weakens and enables the facile cleavage of the X-H or N-N bonds of the ligands. This review presents an overview of coordination-induced bond activation of small molecules by low valent titanium complexes. In particular, the applications of low valent titanium-induced bond weakening in nitrogen fixation are presented. The review concludes with potential future directions for work in this area including low-valent Ti-based PCET systems, photocatalytic nitrogen reduction, and approaches to tailoring complexes for optimal bond activation.
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Affiliation(s)
| | - Robert A Flowers
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
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3
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Chatgilialoglu C, Barata-Vallejo S, Gimisis T. Radical Reactions in Organic Synthesis: Exploring in-, on-, and with-Water Methods. Molecules 2024; 29:569. [PMID: 38338314 PMCID: PMC10856544 DOI: 10.3390/molecules29030569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/18/2024] [Accepted: 01/19/2024] [Indexed: 02/12/2024] Open
Abstract
Radical reactions in water or aqueous media are important for organic synthesis, realizing high-yielding processes under non-toxic and environmentally friendly conditions. This overview includes (i) a general introduction to organic chemistry in water and aqueous media, (ii) synthetic approaches in, on, and with water as well as in heterogeneous phases, (iii) reactions of carbon-centered radicals with water (or deuterium oxide) activated through coordination with various Lewis acids, (iv) photocatalysis in water and aqueous media, and (v) synthetic applications bioinspired by naturally occurring processes. A wide range of chemical processes and synthetic strategies under different experimental conditions have been reviewed that lead to important functional group translocation and transformation reactions, leading to the preparation of complex molecules. These results reveal how water as a solvent/medium/reagent in radical chemistry has matured over the last two decades, with further discoveries anticipated in the near future.
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Affiliation(s)
- Chryssostomos Chatgilialoglu
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, 40129 Bologna, Italy
- Center of Advanced Technologies, Adam Mickiewicz University, 61-712 Poznan, Poland
| | - Sebastian Barata-Vallejo
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, 40129 Bologna, Italy
- Facultad de Farmacia y Bioquímica, Departamento de Ciencias Químicas, Universidad de Buenos Aires, Junin 954, Buenos Aires CP 1113, Argentina
| | - Thanasis Gimisis
- Department of Chemistry, National and Kapodistrian University of Athens, 15771 Athens, Greece
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4
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Zhang J, Mück-Lichtenfeld C, Studer A. Photocatalytic phosphine-mediated water activation for radical hydrogenation. Nature 2023; 619:506-513. [PMID: 37380779 PMCID: PMC10356606 DOI: 10.1038/s41586-023-06141-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/27/2023] [Indexed: 06/30/2023]
Abstract
The chemical activation of water would allow this earth-abundant resource to be transferred into value-added compounds, and is a topic of keen interest in energy research1,2. Here, we demonstrate water activation with a photocatalytic phosphine-mediated radical process under mild conditions. This reaction generates a metal-free PR3-H2O radical cation intermediate, in which both hydrogen atoms are used in the subsequent chemical transformation through sequential heterolytic (H+) and homolytic (H•) cleavage of the two O-H bonds. The PR3-OH radical intermediate provides an ideal platform that mimics the reactivity of a 'free' hydrogen atom, and which can be directly transferred to closed-shell π systems, such as activated alkenes, unactivated alkenes, naphthalenes and quinoline derivatives. The resulting H adduct C radicals are eventually reduced by a thiol co-catalyst, leading to overall transfer hydrogenation of the π system, with the two H atoms of water ending up in the product. The thermodynamic driving force is the strong P=O bond formed in the phosphine oxide by-product. Experimental mechanistic studies and density functional theory calculations support the hydrogen atom transfer of the PR3-OH intermediate as a key step in the radical hydrogenation process.
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Affiliation(s)
- Jingjing Zhang
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Münster, Germany
| | - Christian Mück-Lichtenfeld
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Münster, Germany
- Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität, Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Münster, Germany.
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5
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Mayer JM. Bonds over Electrons: Proton Coupled Electron Transfer at Solid-Solution Interfaces. J Am Chem Soc 2023; 145:7050-7064. [PMID: 36943755 PMCID: PMC10080693 DOI: 10.1021/jacs.2c10212] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
This Perspective argues that most redox reactions of materials at an interface with a protic solution involve net proton-coupled electron transfer (PCET) (or other cation-coupled ET). This view contrasts with the traditional electron-transfer-focused view of redox reactions at semiconductors, but redox processes at metal surfaces are often described as PCET. Taking a thermodynamic perspective, transfer of an electron is typically accompanied by a stoichiometric proton, much as the chemistry of lithium-ion batteries involves coupled transfers of e- and Li+. The PCET viewpoint implicates the surface-H bond dissociation free energy (BDFE) as the preeminent energetic parameter and its conceptual equivalents, the electrochemical ne-/nH+ potential versus the reversible hydrogen electrode (RHE) and the free energy of hydrogenation, ΔG°H. These parameters capture the thermochemistry of PCET at interfaces better than electronic parameters such as Fermi energies, electron chemical potentials, flat-band potentials, or band-edge energies. A unified picture of PCET at metal and semiconductor surfaces is presented. Exceptions, limitations, implications, and future directions motivated by this approach are described.
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Affiliation(s)
- James M Mayer
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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6
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Boekell NG, Bartulovich CO, Maity S, Flowers RA. Accessing Unusual Reactivity through Chelation-Promoted Bond Weakening. Inorg Chem 2023; 62:5040-5045. [PMID: 36912617 DOI: 10.1021/acs.inorgchem.3c00298] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Highly reducing Sm(II) reductants and protic ligands were used as a platform to ascertain the relationship between low-valent metal-protic ligand affinity and degree of ligand X-H bond weakening with the goal of forming potent proton-coupled electron transfer (PCET) reductants. Among the Sm(II)-protic ligand reductant systems investigated, the samarium dibromide N-methylethanolamine (SmBr2-NMEA) reagent system displayed the best combination of metal-ligand affinity and stability against H2 evolution. The use of SmBr2-NMEA afforded the reduction of a range of substrates that are typically recalcitrant to single-electron reduction including alkynes, lactones, and arenes as stable as biphenyl. Moreover, the unique role of NMEA as a chelating ligand for Sm(II) was demonstrated by the reductive cyclization of unactivated esters bearing pendant olefins in contrast to the SmBr2-water-amine system. Finally, the SmBr2-NMEA reagent system was found to reduce substrates analogous to key intermediates in the nitrogen fixation process. These results reveal SmBr2-NMEA to be a powerful reductant for a wide range of challenging substrates and demonstrate the potential for the rational design of PCET reagents with exceptionally weak X-H bonds.
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Affiliation(s)
- Nicholas G Boekell
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Caroline O Bartulovich
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Sandeepan Maity
- Department of Chemistry, C. V. Raman Global University, Bhubaneswar, Odisha 752054, India
| | - Robert A Flowers
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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7
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Lin Q, Tong W, Shu XZ, Chen Y. Ti-Catalyzed Dehydroxylation of Tertiary Alcohols. Org Lett 2022; 24:8459-8464. [DOI: 10.1021/acs.orglett.2c03119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Quan Lin
- School of Materials Science and Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, People’s Republic of China
- Center for Supramolecular Chemistry and Catalysis and Department of Chemistry, College of Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, People’s Republic of China
| | - Weiqi Tong
- Department of Chemistry, College of Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, People’s Republic of China
| | - Xing-Zhong Shu
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, People’s Republic of China
| | - Yunrong Chen
- Center for Supramolecular Chemistry and Catalysis and Department of Chemistry, College of Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, People’s Republic of China
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8
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Cooney SE, Fertig AA, Buisch MR, Brennessel WW, Matson EM. Coordination-induced bond weakening of water at the surface of an oxygen-deficient polyoxovanadate cluster. Chem Sci 2022; 13:12726-12737. [PMID: 36519047 PMCID: PMC9645371 DOI: 10.1039/d2sc04843d] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/10/2022] [Indexed: 10/19/2023] Open
Abstract
Hydrogen-atom (H-atom) transfer at the surface of heterogeneous metal oxides has received significant attention owing to its relevance in energy conversion and storage processes. Here, we present the synthesis and characterization of an organofunctionalized polyoxovanadate cluster, (calix)V6O5(OH2)(OMe)8 (calix = 4-tert-butylcalix[4]arene). Through a series of equilibrium studies, we establish the BDFE(O-H)avg of the aquo ligand as 62.4 ± 0.2 kcal mol-1, indicating substantial bond weaking of water upon coordination to the cluster surface. Subsequent kinetic isotope effect studies and Eyring analysis indicate the mechanism by which the hydrogenation of organic substrates occurs proceeds through a concerted proton-electron transfer from the aquo ligand. Atomistic resolution of surface reactivity presents a novel route of hydrogenation reactivity from metal oxide surfaces through H-atom transfer from surface-bound water molecules.
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Affiliation(s)
- Shannon E Cooney
- Department of Chemistry, University of Rochester Rochester NY 14627 USA
| | - Alex A Fertig
- Department of Chemistry, University of Rochester Rochester NY 14627 USA
| | | | | | - Ellen M Matson
- Department of Chemistry, University of Rochester Rochester NY 14627 USA
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9
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Yang X, Reijerse EJ, Bhattacharyya K, Leutzsch M, Kochius M, Nöthling N, Busch J, Schnegg A, Auer AA, Cornella J. Radical Activation of N-H and O-H Bonds at Bismuth(II). J Am Chem Soc 2022; 144:16535-16544. [PMID: 36053726 PMCID: PMC9479083 DOI: 10.1021/jacs.2c05882] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The development of unconventional strategies for the activation of ammonia (NH3) and water (H2O) is of capital importance for the advancement of sustainable chemical strategies. Herein we provide the synthesis and characterization of a radical equilibrium complex based on bismuth featuring an extremely weak Bi-O bond, which permits the in situ generation of reactive Bi(II) species. The ensuing organobismuth(II) engages with various amines and alcohols and exerts an unprecedented effect onto the X-H bond, leading to low BDFEX-H. As a result, radical activation of various N-H and O-H bonds─including ammonia and water─occurs in seconds at room temperature, delivering well-defined Bi(III)-amido and -alkoxy complexes. Moreover, we demonstrate that the resulting Bi(III)-N complexes engage in a unique reactivity pattern with the triad of H+, H-, and H• sources, thus providing alternative pathways for main group chemistry.
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Affiliation(s)
- Xiuxiu Yang
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Edward J Reijerse
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | | | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Markus Kochius
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Nils Nöthling
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Julia Busch
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Alexander Schnegg
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Alexander A Auer
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Josep Cornella
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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10
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Abstract
Coordination-induced bond weakening is a phenomenon wherein ligand X-H bond homolysis occurs in concert with the energetically favorable oxidation of a coordinating metal complex. The coupling of these two processes enables thermodynamically favorable proton-coupled electron transfer reductions to form weak bonds upon formal hydrogen atom transfer to substrates. Moreover, systems utilizing coordination-induced bond weakening have been shown to facilitate the dehydrogenation of feedstock molecules including water, ammonia, and primary alcohols under mild conditions. The formation of exceptionally weak substrate X-H bonds via small molecule homolysis is a powerful strategy in synthesis and has been shown to enable nitrogen fixation under mild conditions. Coordination-induced bond weakening has also been identified as an integral process in biophotosynthesis and has promising applications in renewable chemical fuel storage systems. This review presents a discussion of the advances made in the study of coordination-induced bond weakening to date. Because of the broad range of metal and ligand species implicated in coordination-induced bond weakening, each literature report is discussed individually and ordered by the identity of the low-valent metal. We then offer mechanistic insights into the basis of coordination-induced bond weakening and conclude with a discussion of opportunities for further research into the development and applications of coordination-induced bond weakening systems.
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Affiliation(s)
- Nicholas G Boekell
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Robert A Flowers
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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11
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Hilche T, Younas SL, Gansäuer A, Streuff J. A Guide to Low‐Valent Titanocene Complexes as Tunable Single‐Electron Transfer Catalysts for Applications in Organic Chemistry. ChemCatChem 2022. [DOI: 10.1002/cctc.202200530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Tobias Hilche
- Rheinische Friedrich-Wilhelms-Universitat Bonn Kekulé-Institut für Organische Chemie und Biochemie Gerhard-Domagk-Str. 1 53121 Bonn GERMANY
| | - Sara L. Younas
- Albert-Ludwigs-Universitat Freiburg Institut für Organische Chemie Albertstr. 21 79104 Freiburg im Breisgau GERMANY
| | - Andreas Gansäuer
- Rheinische Friedrich-Wilhelms-Universitat Bonn Kekulé-Institut für Organische Chemie und Biochemie Gerhard-Domagk-Str. 1 53121 Bonn GERMANY
| | - Jan Streuff
- Uppsala Universitet Department of Chemistry - BMC Husargatan 3 752 37 Uppsala SWEDEN
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12
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Suga T, Takahashi Y, Miki C, Ukaji Y. Direct and Unified Access to Carbon Radicals from Aliphatic Alcohols by Cost-Efficient Titanium-Mediated Homolytic C-OH Bond Cleavage. Angew Chem Int Ed Engl 2022; 61:e202112533. [PMID: 35014149 DOI: 10.1002/anie.202112533] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Indexed: 12/28/2022]
Abstract
Low-valent Ti-mediated homolytic C-O bond cleavage offers unified access to carbon radicals from ubiquitous non-activated tertiary, secondary, and even primary alcohols. In contrast to the representative Ti reagents, which were ineffective for this purpose, "TiCl2 (cat)"/Zn (cat=catecholate) was found to be specifically active. This method was applied to the addition reactions of radicals to alkenes and exhibited high generality and yields. More than 50 combinations were examined. The excellent cost-efficiency and accessibility of "TiCl2 (cat)"/Zn further enhance its applicability. Control experiments proved the presence of a carbon radical intermediate and excluded the pathway via alkyl chlorides. Further mechanistic study indicated that the 1 : 2 complex of alkoxide (R-O- ) and TiIII is an active species in the C-O cleavage.
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Affiliation(s)
- Takuya Suga
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa, 920-1192, Japan
| | - Yuuki Takahashi
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa, 920-1192, Japan
| | - Chinatsu Miki
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa, 920-1192, Japan
| | - Yutaka Ukaji
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa, 920-1192, Japan
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13
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Mondal S, Dumur F, Gigmes D, Sibi MP, Bertrand MP, Nechab M. Enantioselective Radical Reactions Using Chiral Catalysts. Chem Rev 2022; 122:5842-5976. [DOI: 10.1021/acs.chemrev.1c00582] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Shovan Mondal
- Department of Chemistry, Syamsundar College, Shyamsundar 713424, West Bengal, India
| | - Frédéric Dumur
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
| | - Didier Gigmes
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
| | - Mukund P. Sibi
- Department of Chemistry and Biochemistry North Dakota State University, Fargo, North Dakota 58108, United States
| | - Michèle P. Bertrand
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
| | - Malek Nechab
- Aix Marseille Univ, CNRS, Institut de Chimie Radicalaire UMR 7273, F-13390e Marseille, France
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14
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Xie Y, Miao Q, Deng W, Lu Y, Yang Y, Chen X, Liao RZ, Ye S, Tung CH, Wang W. Facile Transformations of a Binuclear Cp*Co(II) Diamidonaphthalene Complex to Mixed-Valent Co(II)Co(III), Co(III)(μ-H)Co(III), and Co(III)(μ-OH)Co(III) Derivatives. Inorg Chem 2022; 61:2204-2210. [PMID: 35049285 DOI: 10.1021/acs.inorgchem.1c03451] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A diamido-bridged dicobalt complex supported by a diamidonaphthalene ligand, Cp*2Co2(μ-1,8-C10H8(NH)2) (1), was synthesized, and the reactivity relevant to redox transformations of the Co2N2 core was investigated. It was found that the Co(II)-Co(II) bond allows for protonation by [HPPh3][BF4] resulting in a bridging hydride, [1H]+, with pKa ∼ 7.6 in CH2Cl2. The diamidonaphthalene ligand can stabilize the binuclear system in the Co(II)Co(III) mixed-valent state (1+), which is capable of binding CO to afford [1-CO]+. Surprisingly, the mixed-valent complex also activates H2O to furnish a Co(III)Co(III) hydroxy complex [1-OH]+ accompanied by release of H2. The hydroxy ligand in [1-OH]+ is exchangeable, as demonstrated by 18O-labeling experiments on [1-OH]+ with H218O that led to the heavier isotopolog [1-18OH]+.
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Affiliation(s)
- Yufang Xie
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Qiyi Miao
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Wenhao Deng
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yilei Lu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Yinuo Yang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Xiaohui Chen
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Rong-Zhen Liao
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shengfa Ye
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Wenguang Wang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.,College of Chemistry, Beijing Normal University, Beijing 100875, China
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15
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Matsunaga K, Endo R, Nagasawa K, Kishida A, Takatori K. Synthesis of Succinonitrile Derivatives by Homocoupling from Cyanohydrin Derivatives with a Low-Valent Titanium Reagent. J Org Chem 2022; 87:3707-3711. [PMID: 35049306 DOI: 10.1021/acs.joc.1c02643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A method is described for synthesizing succinonitrile derivatives bearing alkyl or aryl substituents from cyanohydrin derivatives using low-valent titanium. The active species in this reaction is proposed to be a resonance hybrid of the TiIV nitrile enolate and TiIII alkyl radical.
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Affiliation(s)
- Kazuma Matsunaga
- Graduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan
| | - Ryusei Endo
- Graduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan
| | - Kokoro Nagasawa
- Graduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan
| | - Atsushi Kishida
- Graduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan
| | - Kazuhiko Takatori
- Graduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan
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16
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Suga T, Takahashi Y, Miki C, Ukaji Y. Direct and Unified Access to Carbon Radicals from Aliphatic Alcohols by Cost‐Efficient Titanium‐Mediated Homolytic C–OH Bond Cleavage. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Takuya Suga
- Kanazawa University Graduate School of Natural Science Kakuma 920-1192 Kanazawa JAPAN
| | - Yuuki Takahashi
- Kanazawa University: Kanazawa Daigaku Division of Material Chemistry, Graduate School of Natural Science and Technology JAPAN
| | - Chinatsu Miki
- Kanazawa University: Kanazawa Daigaku Division of Material Chemistry, School of Natural Science and Technology JAPAN
| | - Yutaka Ukaji
- Kanazawa University: Kanazawa Daigaku Division of Material Chemistry, School of Natural Science and Technology JAPAN
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17
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Avilés A, Colmenares F. Exploring the potential of the ammine complexes M(NH 3) n+ (M = Zr, Re) to activate NH 3. NEW J CHEM 2022. [DOI: 10.1039/d1nj05386h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
NH3 is activated by the complex Zr(NH3)7+ through a mechanism involving radical species.
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Affiliation(s)
- Alejandro Avilés
- Departamento de Física y Química Teórica, Facultad de Química, Universidad Nacional Autónoma de México, CDMX 04510, Mexico
| | - Fernando Colmenares
- Departamento de Física y Química Teórica, Facultad de Química, Universidad Nacional Autónoma de México, CDMX 04510, Mexico
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18
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Peper JL, Gentry NE, Boudy B, Mayer JM. Aqueous TiO 2 Nanoparticles React by Proton-Coupled Electron Transfer. Inorg Chem 2021; 61:767-777. [PMID: 34967207 DOI: 10.1021/acs.inorgchem.1c03125] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Redox reactions of aqueous colloidal TiO2 4 nm nanoparticles (NPs) have been examined, including both citrate-capped and uncapped NPs (c-TiO2 and uc-TiO2). Photoreduction gave stable blue colloidal c-TiO2R NPs with 10-60 electrons per particle. Equilibration of these reduced NPs with soluble redox reagents such as methylviologen (MV2+) provided measurements of the colloid reduction potential as a function of pH. The potentials of c-TiO2 from pH 2-9 varied linearly with pH, with a slope of -60 ± 5 mV/pH. Estimates of the potential at pH 12 were consistent with extrapolating that line to high pH. The reduction potentials did not correlate with the zeta potentials (ζ) or the surface charge of the NPs across this pH range. Similar reduction potentials were observed for c- and uc-TiO2 at low pH even though they have quite different ζ potentials. These results show that the common surface-charging explanation of the pH dependence is not tenable in these systems. Oxidation of reduced c-TiO2R with the electron-transfer oxidant potassium triiodide (KI3) occurred with a significant drop in pH, showing that protons were released when the electrons were removed from the NPs. Smaller pH drops were observed for the proton-coupled electron transfer (PCET) reagents O2 (air) and 4-MeO-TEMPO (4-methoxy-2,2,6,6-tetramethylpiperine-1-oxy radical). The difference in the number of protons released with KI3 vs O2 and 4-MeO-TEMPO was roughly one proton per electron removed. Thus, the thermodynamically preferred reactivity of these colloidal TiO2 NPs is PCET over the pH 2-13 range studied. The measured redox potentials refer to the chemical process TiO2 + H+ + e- → TiO2·e-,H+; and therefore they do not correspond with an electronic energy such as a conduction band edge or flat band potential. The 1e-/1H+ stoichiometry means that the TiO2 reduction potentials correspond to a TiO2-H bond dissociation free energy (BDFE), determined to be 49 ± 2 kcal mol-1. The PCET description is consistent with the pH dependence of E(TiO2/TiO2·e-,H+), the release of protons upon oxidation, the lack of correlation with ζ potentials, the similarity of capped and uncapped NPs, and the small change in the potential and BDFE from the first to the last electron/proton pair (H atom) removed. This behavior is suggested to be the norm for redox-active oxide/water interfaces.
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Affiliation(s)
- Jennifer L Peper
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Noreen E Gentry
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Benjamin Boudy
- 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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19
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Arvapalli DM, Sheardy AT, Bang JJ, Wei J. Antiproliferative and ROS Regulation Activity of Photoluminescent Curcumin-Derived Nanodots. ACS APPLIED BIO MATERIALS 2021; 4:8477-8486. [PMID: 35005943 DOI: 10.1021/acsabm.1c00991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Recently, various types of nanomaterials have been employed to design delivery vehicles for curcumin to address the problems of poor bioavailability, low aqueous solubility, and rapid metabolism. The present study focuses on a direct one-pot synthesis of curcumin-derived nanoparticles and exploits their potential therapeutic properties in cancer cells in vitro without additional delivery vehicles. The nanoparticles, named E-Curc-dots, are synthesized using three precursor molecules, ethylenediamine (EDA), curcumin, and citric acid. The structure, composition, and physichemical properties of the nanodots are characterized and identified by employing spectroscopic and microscopic techniques. The as-synthesized E-Curc-dots exhibit bright blue photoluminescence due to the incorporation of nitrogen from the EDA precursor molecule. The characterization studies show a uniform distribution of dots with an average size of 4.6 ± 1.7 nm and, notably, that the dots retain some of the major characteristics of native curcumin with much improved water solubility and bioavailability. The E-Curc-dots show antioxidation activity at low concentrations (<0.08 mg/mL) with low levels of reactive oxygen species (ROS) generation, i.e., 82% of the ROS level in cells without treatment for A549 cells; however, at high concentrations, the nanodots exhibit a pro-oxidant effect on both the cancer cells (A549) and normal cells (EA.hy926) by inducing more ROS generation and dose-dependent cytotoxicity. The E-Curc-dots demonstrate higher cytotoxicity toward cancer cells compared to native curcumin at a lower concentration. The results indicate the efficacy of E-Curc-dots as an antiproliferative and ROS regulator with the ability of cellular bioimaging.
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Affiliation(s)
- Durga M Arvapalli
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, North Carolina 27401, United States
| | - Alex T Sheardy
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, North Carolina 27401, United States
| | - John J Bang
- Department of Environmental, Earth and Geospatial Sciences, North Carolina Central University, Durham, North Carolina 27707, United States
| | - Jianjun Wei
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, North Carolina 27401, United States
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20
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Agarwal RG, Coste SC, Groff BD, Heuer AM, Noh H, Parada GA, Wise CF, Nichols EM, Warren JJ, Mayer JM. Free Energies of Proton-Coupled Electron Transfer Reagents and Their Applications. Chem Rev 2021; 122:1-49. [PMID: 34928136 DOI: 10.1021/acs.chemrev.1c00521] [Citation(s) in RCA: 134] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We present an update and revision to our 2010 review on the topic of proton-coupled electron transfer (PCET) reagent thermochemistry. Over the past decade, the data and thermochemical formalisms presented in that review have been of value to multiple fields. Concurrently, there have been advances in the thermochemical cycles and experimental methods used to measure these values. This Review (i) summarizes those advancements, (ii) corrects systematic errors in our prior review that shifted many of the absolute values in the tabulated data, (iii) provides updated tables of thermochemical values, and (iv) discusses new conclusions and opportunities from the assembled data and associated techniques. We advocate for updated thermochemical cycles that provide greater clarity and reduce experimental barriers to the calculation and measurement of Gibbs free energies for the conversion of X to XHn in PCET reactions. In particular, we demonstrate the utility and generality of reporting potentials of hydrogenation, E°(V vs H2), in almost any solvent and how these values are connected to more widely reported bond dissociation free energies (BDFEs). The tabulated data demonstrate that E°(V vs H2) and BDFEs are generally insensitive to the nature of the solvent and, in some cases, even to the phase (gas versus solution). This Review also presents introductions to several emerging fields in PCET thermochemistry to give readers windows into the diversity of research being performed. Some of the next frontiers in this rapidly growing field are coordination-induced bond weakening, PCET in novel solvent environments, and reactions at material interfaces.
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Affiliation(s)
- Rishi G Agarwal
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Scott C Coste
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Benjamin D Groff
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Abigail M Heuer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Hyunho Noh
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Giovanny A Parada
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.,Department of Chemistry, The College of New Jersey, Ewing, New Jersey 08628, United States
| | - Catherine F Wise
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Eva M Nichols
- Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Jeffrey J Warren
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - James M Mayer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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21
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Ramírez-Solís A, Boekell NG, León-Pimentel CI, Saint-Martin H, Bartulovich CO, Flowers RA. Ammonia Solvation vs Aqueous Solvation of Samarium Diiodide. A Theoretical and Experimental Approach to Understanding Bond Activation Upon Coordination to Sm(II). J Org Chem 2021; 87:1689-1697. [PMID: 34775764 DOI: 10.1021/acs.joc.1c01771] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Coordination-induced desolvation or ligand displacement by cosolvents and additives is a key feature responsible for the reactivity of Sm(II)-based reagent systems. High-affinity proton donor cosolvents such as water and glycols also demonstrate coordination-induced bond weakening of the O-H bond, facilitating reduction of a broad range of substrates. In the present work, the coordination of ammonia to SmI2 was examined using Born-Oppenheimer molecular dynamics simulations and mechanistic studies, and the SmI2-ammonia system is compared to the SmI2-water system. The coordination number and reactivity of the SmI2-ammonia solvent system were found to be similar to those of SmI2-water but exhibited an order of magnitude greater rate of arene reduction by SmI2-ammonia than by SmI2-water at the same concentrations of cosolvent. In addition, upon coordination of ammonia to SmI2, the Sm(II)-ammonia solvate demonstrates one of the largest degrees of N-H bond weakening reported in the literature compared to known low-valent transition metal ammonia complexes.
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Affiliation(s)
- Alejandro Ramírez-Solís
- Depto. de Física, Centro de Investigación en Ciencias-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos 62209, México
| | - Nicholas G Boekell
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | | | | | - Caroline O Bartulovich
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Robert A Flowers
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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22
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Warburton RE, Mayer JM, Hammes-Schiffer S. Proton-Coupled Defects Impact O-H Bond Dissociation Free Energies on Metal Oxide Surfaces. J Phys Chem Lett 2021; 12:9761-9767. [PMID: 34595925 DOI: 10.1021/acs.jpclett.1c02837] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Proton-coupled electron transfer (PCET) reactions on metal oxides require coupling between proton transfer at the solid-liquid interface and electron transfer involving defects at or near the band edge. Herein, hybrid functional periodic density functional theory is used to elucidate the impact of proton-coupled defects on the bond dissociation free energies (BDFEs) of O-H bonds on anatase TiO2 surfaces. These O-H BDFEs are directly related to interfacial PCET thermochemistry. Comparison between geometrically similar O-H bonds associated with different defect types, namely conduction d-band electrons or valence p-band holes, reveals that the BDFEs differ by ∼81 kcal/mol (3.50 eV), comparable to the wide TiO2 band gap. These differences are shown to be determined primarily by differences in electron transfer driving forces, which are analyzed by using band energies and inner-sphere reorganization energies within a Marcus theory framework. These fundamental insights about the impact of proton-coupled defects on PCET thermochemistry at semiconductor surfaces have broad implications for electrocatalysis.
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Affiliation(s)
- Robert E Warburton
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - James M Mayer
- 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
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23
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Younas SL, Streuff J. Kinetic Analysis Uncovers Hidden Autocatalysis and Inhibition Pathways in Titanium(III)-Catalyzed Ketone-Nitrile Couplings. ACS Catal 2021. [DOI: 10.1021/acscatal.1c02870] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Sara L. Younas
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany
| | - Jan Streuff
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany
- Department of Chemistry—BMC, Uppsala University, Husargatan 3, 75237 Uppsala, Sweden
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24
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Wong A, Chakraborty A, Bawari D, Wu G, Dobrovetsky R, Ménard G. Facile proton-coupled electron transfer enabled by coordination-induced E-H bond weakening to boron. Chem Commun (Camb) 2021; 57:6903-6906. [PMID: 34151918 DOI: 10.1039/d1cc02832d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the facile activation of aryl E-H (ArEH; E = N, O, S; Ar = Ph or C6F5) or ammonia N-H bonds via coordination-induced bond weakening to a redox-active boron center in the complex, (1-). Substantial decreases in E-H bond dissociation free energies (BDFEs) are observed upon substrate coordination, enabling subsequent facile proton-coupled electron transfer (PCET). A drop of >50 kcal mol-1 in H2N-H BDFE upon coordination was experimentally determined.
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Affiliation(s)
- Anthony Wong
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA.
| | - Arunavo Chakraborty
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA.
| | - Deependra Bawari
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA.
| | - Roman Dobrovetsky
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Gabriel Ménard
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA.
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25
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Wang Z, Johnson SI, Wu G, Ménard G. Multiple N-H and C-H Hydrogen Atom Abstractions Through Coordination-Induced Bond Weakening at Fe-Amine Complexes. Inorg Chem 2021; 60:8242-8251. [PMID: 34011142 DOI: 10.1021/acs.inorgchem.1c00923] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the use of the reported Fe-phthalocyanine complex, PcFe (1; Pc = 1,4,8,11,15,18,22,25-octaethoxy-phthalocyanine), to generate PcFe-amine complexes 1-(NH3)2, 1-(MeNH2)2, and 1-(Me2NH)2. Treatment of 1 or 1-(NH3)2 to an excess of the stable aryloxide radical, 2,4,6-tritert-butylphenoxyl radical (tBuArO•), under NH3 resulted in catalytic H atom abstraction (HAA) and C-N coupling to generate the product 4-amino-2,4,6-tritert-butylcyclohexa-2,5-dien-1-one (2) and tBuArOH. Exposing 1-(NH3)2 to an excess of the trityl (CPh3) variant, 2,6-di-tert-butyl-4-tritylphenoxyl radical (TrArO•), under NH3 did not lead to catalytic ammonia oxidation as previously reported in a related Ru-porphyrin complex. However, pronounced coordination-induced bond weakening of both α N-H and β C-H in the alkylamine congeners, 1-(MeNH2)2 and 1-(Me2NH)2, led to multiple HAA events yielding the unsaturated cyanide complex, 1-(MeNH2)(CN), and imine complex, 1-(MeN═CH2)2, respectively. Subsequent C-N bond formation was also observed in the latter upon addition of a coordinating ligand. Detailed computational studies support an alternating mechanism involving sequential N-H and C-H HAA to generate these unsaturated products.
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Affiliation(s)
- Zongheng Wang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Samantha I Johnson
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Gabriel Ménard
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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26
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Avilés A, Torres AE, Colmenares F. Low‐Energy Pathways Found for the NH
3
Activation and H
2
Elimination by the Werner‐Type Complexes M(NH
3
)
4
+
(M=Fe, Ru and Os). ChemistrySelect 2020. [DOI: 10.1002/slct.202003816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Alejandro Avilés
- Departamento de Física y Química Teórica Facultad de Química Universidad Nacional Autónoma de México México CDMX. 04510 Mexico
| | - Ana E. Torres
- Departamento de Micro y Nanotecnologías Instituto de Ciencias Aplicadas y Tecnología Universidad Nacional Autónoma de México México CDMX. 04510 Mexico
| | - Fernando Colmenares
- Departamento de Física y Química Teórica Facultad de Química Universidad Nacional Autónoma de México México CDMX. 04510 Mexico
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27
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Shevick SL, Wilson CV, Kotesova S, Kim D, Holland PL, Shenvi RA. Catalytic hydrogen atom transfer to alkenes: a roadmap for metal hydrides and radicals. Chem Sci 2020; 11:12401-12422. [PMID: 33520153 PMCID: PMC7810138 DOI: 10.1039/d0sc04112b] [Citation(s) in RCA: 122] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/28/2020] [Indexed: 12/12/2022] Open
Abstract
Hydrogen atom transfer from metal hydrides to alkenes appears to underlie widely used catalytic methods – the mechanistic implications are fascinating.
Hydrogen atom transfer from a metal hydride (MHAT) has emerged as a powerful, if puzzling, technique in chemical synthesis. In catalytic MHAT reactions, earth-abundant metal complexes generate stabilized and unstabilized carbon-centered radicals from alkenes of various substitution patterns with robust chemoselectivity. This perspective combines organic and inorganic perspectives to outline challenges and opportunities, and to propose working models to assist further developments. We attempt to demystify the putative intermediates, the basic elementary steps, and the energetic implications, especially for cage pair formation, collapse and separation. Distinctions between catalysts with strong-field (SF) and weak-field (WF) ligand environments may explain some differences in reactivity and selectivity, and provide an organizing principle for kinetics that transcends the typical thermodynamic analysis. This blueprint should aid practitioners who hope to enter and expand this exciting area of chemistry.
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Affiliation(s)
- Sophia L Shevick
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , CA 92037 , USA
| | - Conner V Wilson
- Department of Chemistry , Yale University , 225 Prospect St. , New Haven , CT 06511 , USA
| | - Simona Kotesova
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , CA 92037 , USA
| | - Dongyoung Kim
- Department of Chemistry , Yale University , 225 Prospect St. , New Haven , CT 06511 , USA
| | - Patrick L Holland
- Department of Chemistry , Yale University , 225 Prospect St. , New Haven , CT 06511 , USA
| | - Ryan A Shenvi
- Department of Chemistry , Scripps Research , 10550 North Torrey Pines Road , La Jolla , CA 92037 , USA
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28
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Fermi A, Gualandi A, Bergamini G, Cozzi PG. Shining Light on Ti
IV
Complexes: Exceptional Tools for Metallaphotoredox Catalysis. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000966] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Andrea Fermi
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
| | - Andrea Gualandi
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
| | - Giacomo Bergamini
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
| | - Pier Giorgio Cozzi
- Dipartimento di Chimica "G. Ciamician" Università di Bologna via Selmi 2 40126 Bologna Italy
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29
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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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30
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Feng S, Chen C, Chan KS. Rhodium Porphyrin Catalyzed Regioselective Hydrogenolysis of 1,2-Diarylcyclopropanes with Water as the Hydrogen Source. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shiyu Feng
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, People’s Republic of China
| | - Chen Chen
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, People’s Republic of China
| | - Kin Shing Chan
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, People’s Republic of China
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31
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Ramírez-Solís A, Bartulovich CO, León-Pimentel CI, Saint-Martin H, Boekell NG, Flowers RA. Proton donor effects on the reactivity of SmI2. Experimental and theoretical studies on methanol solvation vs. aqueous solvation. Dalton Trans 2020; 49:7897-7902. [DOI: 10.1039/d0dt01221a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Using both computational and experimental data the SmI2–MeOH system is directly compared to the SmI2–H2O system to uncover the basis for their drastic differences in reactivity.
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Affiliation(s)
- Alejandro Ramírez-Solís
- Depto. de Física
- Centro de Investigación en Ciencias-IICBA Universidad Autónoma del Estado de Morelos
- Cuernavaca
- Mexico
| | | | - César Iván León-Pimentel
- Depto. de Física
- Centro de Investigación en Ciencias-IICBA Universidad Autónoma del Estado de Morelos
- Cuernavaca
- Mexico
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32
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González-Delgado JA, Arteaga JF. Control of Homocoupling Versus Reduction in Titanium(III)-Mediated Radical Opening of Styrene Oxides. European J Org Chem 2019. [DOI: 10.1002/ejoc.201901625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- José A. González-Delgado
- CIQSO-Center for Research in Sustainable Chemistry and Department of Chemistry; University of Huelva; Campus de El Carmen s/n E-21071 Huelva Spain
| | - Jesús F. Arteaga
- CIQSO-Center for Research in Sustainable Chemistry and Department of Chemistry; University of Huelva; Campus de El Carmen s/n E-21071 Huelva Spain
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33
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Klare S, Gordon JP, Gansäuer A, RajanBabu TV, Nugent WA. The Reaction of β,γ-Epoxy Alcohols with Titanium(III) Reagents. A Proposed Role for Intramolecular Hydrogen Bonding. Tetrahedron 2019; 75:130662. [PMID: 32601512 PMCID: PMC7322769 DOI: 10.1016/j.tet.2019.130662] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Sven Klare
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straβe 1, 53121 Bonn, Germany
| | - Jonathan P. Gordon
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210 USA
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straβe 1, 53121 Bonn, Germany
| | - T. V. RajanBabu
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210 USA
| | - William A. Nugent
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210 USA
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34
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Carmona M, Ferrer J, Rodríguez R, Passarelli V, Lahoz FJ, García-Orduña P, Cañadillas-Delgado L, Carmona D. Reversible Activation of Water by an Air- and Moisture-Stable Frustrated Rhodium Nitrogen Lewis Pair. Chemistry 2019; 25:13665-13670. [PMID: 31353749 DOI: 10.1002/chem.201902452] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/12/2019] [Indexed: 12/15/2022]
Abstract
[Cp*Rh(κ3 N,N',P-L)][SbF6 ] (Cp*=C5 Me5 ), bearing a guanidine-derived phosphano ligand L, behaves as a "dormant" frustrated Lewis pair and activates H2 and H2 O in a reversible manner. When D2 O is employed, a facile H/D exchange at the Cp* ring takes place through sequential C(sp3 )-H bond activation.
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Affiliation(s)
- María Carmona
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Joaquina Ferrer
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Ricardo Rodríguez
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Vincenzo Passarelli
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain.,Centro Universitario de la Defensa, Ctra. Huesca s/n, 50090, Zaragoza, Spain
| | - Fernando J Lahoz
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Pilar García-Orduña
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - Laura Cañadillas-Delgado
- Centro Universitario de la Defensa, Ctra. Huesca s/n, 50090, Zaragoza, Spain.,Institut Laue-Langevin, 71 Avenue des Martyrs, Grenoble, 38042, France
| | - Daniel Carmona
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain
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35
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Ramírez-Solís A, Bartulovich CO, León-Pimentel CI, Saint-Martin H, Anderson WR, Flowers RA. Experimental and Theoretical Studies on the Aqueous Solvation and Reactivity of SmCl2 and Comparison with SmBr2 and SmI2. Inorg Chem 2019; 58:13927-13932. [DOI: 10.1021/acs.inorgchem.9b01818] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Alejandro Ramírez-Solís
- Departamento de Física, Centro de Investigación en Ciencias-IICBA Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos 62209, Mexico
| | | | | | | | - William R. Anderson
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Robert A. Flowers
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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36
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Liedtke T, Hilche T, Klare S, Gansäuer A. Condition Screening for Sustainable Catalysis in Single-Electron Steps by Cyclic Voltammetry: Additives and Solvents. CHEMSUSCHEM 2019; 12:3166-3171. [PMID: 30779429 DOI: 10.1002/cssc.201900344] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 02/18/2019] [Indexed: 06/09/2023]
Abstract
Cyclic voltammetry-based screening method for Cp2 TiX-catalyzed reactions is extended to the screening of solvents other than tetrahydrofuran for bulk electrolysis of the catalyst and radical arylation. It was found that CH3 CN can be used as a solvent for both processes without additives. Furthermore, in tetrahydrofuran, squaramide L2 is more efficient than the previously reported supramolecular halide binder, Schreiner's thiourea L1. The results extend the usefulness of the proposed time and resource-efficient screening method for designing catalysis reactions in single-electron steps.
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Affiliation(s)
- Theresa Liedtke
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Tobias Hilche
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Sven Klare
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
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37
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Kim D, Rahaman SMW, Mercado BQ, Poli R, Holland PL. Roles of Iron Complexes in Catalytic Radical Alkene Cross-Coupling: A Computational and Mechanistic Study. J Am Chem Soc 2019; 141:7473-7485. [PMID: 31025567 PMCID: PMC6953484 DOI: 10.1021/jacs.9b02117] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A growing and useful class of alkene coupling reactions involve hydrogen atom transfer (HAT) from a metal-hydride species to an alkene to form a free radical, which is responsible for subsequent bond formation. Here, we use a combination of experimental and computational investigations to map out the mechanistic details of iron-catalyzed reductive alkene cross-coupling, an important representative of the HAT alkene reactions. We are able to explain several observations that were previously mysterious. First, the rate-limiting step in the catalytic cycle is the formation of the reactive Fe-H intermediate, elucidating the importance of the choice of reductant. Second, the success of the catalytic system is attributable to the exceptionally weak (17 kcal/mol) Fe-H bond, which performs irreversible HAT to alkenes in contrast to previous studies on isolable hydride complexes where this addition was reversible. Third, the organic radical intermediates can reversibly form organometallic species, which helps to protect the free radicals from side reactions. Fourth, the previously accepted quenching of the postcoupling radical through stepwise electron transfer/proton transfer is not as favorable as alternative mechanisms. We find that there are two feasible pathways. One uses concerted proton-coupled electron transfer (PCET) from an iron(II) ethanol complex, which is facilitated because the O-H bond dissociation free energy is lowered by 30 kcal/mol upon metal binding. In an alternative pathway, an O-bound enolate-iron(III) complex undergoes proton shuttling from an iron-bound alcohol. These kinetic, spectroscopic, and computational studies identify key organometallic species and PCET steps that control selectivity and reactivity in metal-catalyzed HAT alkene coupling, and create a firm basis for elucidation of mechanisms in the growing class of HAT alkene cross-coupling reactions.
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Affiliation(s)
- Dongyoung Kim
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - S. M. Wahidur Rahaman
- LCC-CNRS, Université de Toulouse, INPT, 205 Route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France
| | - Brandon Q. Mercado
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Rinaldo Poli
- LCC-CNRS, Université de Toulouse, INPT, 205 Route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France
| | - Patrick L. Holland
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
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38
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Chang MC, Jesse KA, Filatov AS, Anderson JS. Reversible homolytic activation of water via metal-ligand cooperativity in a T-shaped Ni(ii) complex. Chem Sci 2019; 10:1360-1367. [PMID: 30809351 PMCID: PMC6354739 DOI: 10.1039/c8sc03719a] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/05/2018] [Indexed: 12/18/2022] Open
Abstract
A T-shaped Ni(ii) complex [Tol,PhDHPy]Ni has been prepared and characterized. EPR spectra and DFT calculations of this complex suggest that the electronic structure is best described as a high-spin Ni(ii) center antiferromagnetically coupled with a ligand-based radical. This complex reacts with water at room temperature to generate the dimeric complex [Tol,PhDHPy]Ni(μ-OH)Ni[Tol,PhDHPyH] which has been thoroughly characterized by SXRD, NMR, IR and deuterium-labeling experiments. Addition of simple ligands such as phosphines or pyridine displaces water and demonstrates the reversibility of water activation in this system. The water activation step has been examined by kinetic studies and DFT calculations which suggest an unusual homolytic reaction via a bimetallic mechanism. The ΔH ‡, ΔS ‡ and KIE (k H/k D) of the reaction are 5.5 kcal mol-1, -23.8 cal mol-1 K-1, and 2.4(1), respectively. In addition to the reversibility of water addition, this system is capable of activating water towards net O-atom transfer to substrates such as aromatic C-H bonds and phosphines. This reactivity is facilitated by the ability of the dihydrazonopyrrole ligand to accept H-atoms and illustrates the utility of metal ligand cooperation in activating O-H bonds with high bond dissociation energies.
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Affiliation(s)
- Mu-Chieh Chang
- Department of Chemistry , The University of Chicago , Chicago , Illinois 60637 , USA .
| | - Kate A Jesse
- Department of Chemistry , The University of Chicago , Chicago , Illinois 60637 , USA .
| | - Alexander S Filatov
- Department of Chemistry , The University of Chicago , Chicago , Illinois 60637 , USA .
| | - John S Anderson
- Department of Chemistry , The University of Chicago , Chicago , Illinois 60637 , USA .
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39
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Ji Z, Sheardy A, Zeng Z, Zhang W, Chevva H, Allado K, Yin Z, Wei J. Tuning the Functional Groups on Carbon Nanodots and Antioxidant Studies. Molecules 2019; 24:E152. [PMID: 30609752 PMCID: PMC6337175 DOI: 10.3390/molecules24010152] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/08/2018] [Accepted: 12/12/2018] [Indexed: 11/29/2022] Open
Abstract
Carbon nanodots (CNDs) have shown good antioxidant capabilities by scavenging oxidant free radicals such as diphenyl-1-picrylhydrazyl radical (DPPH•) and reactive oxygen species. While some studies suggest that the antioxidation activities associate to the proton donor role of surface active groups like carboxyl groups (⁻COOH), it is unclear how exactly the extent of oxidant scavenging potential and its related mechanisms are influenced by functional groups on CNDs' surfaces. In this work, carboxyl and the amino functional groups on CNDs' surfaces are modified to investigate the individual influence of intermolecular interactions with DPPH• free radical by UV-Vis spectroscopy and electrochemistry. The results suggest that both the carboxyl and the amino groups contribute to the antioxidation activity of CNDs through either a direct or indirect hydrogen atom transfer reaction with DPPH•.
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Affiliation(s)
- Zuowei Ji
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA.
| | - Alex Sheardy
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA.
| | - Zheng Zeng
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA.
| | - Wendi Zhang
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA.
| | - Harish Chevva
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA.
| | - Kokougan Allado
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA.
| | - Ziyu Yin
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA.
| | - Jianjun Wei
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA.
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40
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Resa S, Millán A, Fuentes N, Crovetto L, Luisa Marcos M, Lezama L, Choquesillo-Lazarte D, Blanco V, Campaña AG, Cárdenas DJ, Cuerva JM. O–H and (CO)N–H bond weakening by coordination to Fe(ii). Dalton Trans 2019; 48:2179-2189. [DOI: 10.1039/c8dt04689a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Coordination of hydroxyl/amide groups to Fe(ii) diminishes BDFEs of O–H and (CO)N–H bonds down to 76.0 and 80.5 kcal mol−1 respectively.
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41
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Beaumier EP, Pearce AJ, See XY, Tonks IA. Modern applications of low-valent early transition metals in synthesis and catalysis. Nat Rev Chem 2019; 3:15-34. [PMID: 30989127 PMCID: PMC6462221 DOI: 10.1038/s41570-018-0059-x] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Low-valent early transition metals are often intrinsically highly reactive as a result of their strong propensity toward oxidation to more stable high-valent states. Harnessing these highly reducing complexes for productive reactivity is potentially powerful for C-C bond construction, organic reductions, small-molecule activation and many other reactions that offer orthogonal chemoselectivity and/or regioselectivity patterns to processes promoted by late transition metals. Recent years have seen many exciting new applications of low-valent metals through building new catalytic and/or multicomponent reaction manifolds out of classical reactivity patterns. In this Review, we survey new methods that employ early transition metals and invoke low-valent precursors or intermediates in order to identify common themes and strategies in synthesis and catalysis.
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Affiliation(s)
- Evan P. Beaumier
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Adam J. Pearce
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Xin Yi See
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Ian A. Tonks
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
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42
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Bartulovich CO, Flowers RA. Coordination-induced O–H bond weakening in Sm(ii)-water complexes. Dalton Trans 2019; 48:16142-16147. [DOI: 10.1039/c9dt03352a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Coordination of water to low-valent Sm leads to O–H bond-weakening that enables PCET to substrates.
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Affiliation(s)
| | - R. A. Flowers
- Department of Chemistry Lehigh University
- Bethlehem
- USA
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43
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Ramírez-Solís A, Bartulovich CO, Chciuk TV, Hernández-Cobos J, Saint-Martin H, Maron L, Anderson WR, Li AM, Flowers RA. Experimental and Theoretical Studies on the Implications of Halide-Dependent Aqueous Solvation of Sm(II). J Am Chem Soc 2018; 140:16731-16739. [DOI: 10.1021/jacs.8b09857] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Alejandro Ramírez-Solís
- Departamento de Física, Centro de Investigación en Ciencias-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos 62209 México
| | | | - Tesia V. Chciuk
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Jorge Hernández-Cobos
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
| | - Humberto Saint-Martin
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
| | - Laurent Maron
- Laboratoire de Physique et Chimie de Nano-objets, Université de Toulouse, INSA-CNRS-UPS, 135, Avenue de Rangueil, 31077 Toulouse, France
| | - William R. Anderson
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Anna M. Li
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Robert A. Flowers
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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44
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Yang W, Chen C, Chan KS. Hydrodebromination of allylic and benzylic bromides with water catalyzed by a rhodium porphyrin complex. Dalton Trans 2018; 47:12879-12883. [PMID: 30168570 DOI: 10.1039/c8dt02168f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrodebromination of allylic and benzylic bromides was successfully achieved by a rhodium porphyrin complex catalyst using water as the hydrogen source without a sacrificial reductant. Mechanistic investigations suggest that bromine atom abstraction via a rhodium porphyrin metalloradical operates to give the rhodium porphyrin alkyl species and the subsequent hydrolysis of the rhodium porphyrin alkyl species to a hydrocarbon product is a key step to harness the hydrogen from water.
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Affiliation(s)
- Wu Yang
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, People's Republic of China.
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45
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Yan J, Yang Z, Chen Y, Chang Y, Lyu C, Luo C, Cheng M, Hsu H. Activation of O−H and C−O Bonds in Water and Methanol by a Vanadium‐Bound Thiyl Radical. Chemistry 2018; 24:15190-15194. [DOI: 10.1002/chem.201803431] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 07/17/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Jyun‐An Yan
- Department of ChemistryNational Cheng Kung University, No. 1 University Rd. 701 Tainan Taiwan
| | - Zi‐Kuan Yang
- Department of ChemistryNational Cheng Kung University, No. 1 University Rd. 701 Tainan Taiwan
| | - Yu‐Sen Chen
- Department of ChemistryNational Cheng Kung University, No. 1 University Rd. 701 Tainan Taiwan
| | - Ya‐Ho Chang
- Department of ChemistryNational Cheng Kung University, No. 1 University Rd. 701 Tainan Taiwan
| | - Chiao‐Ling Lyu
- Department of ChemistryNational Cheng Kung University, No. 1 University Rd. 701 Tainan Taiwan
| | - Chun‐Gang Luo
- Department of ChemistryNational Cheng Kung University, No. 1 University Rd. 701 Tainan Taiwan
| | - Mu‐Jeng Cheng
- Department of ChemistryNational Cheng Kung University, No. 1 University Rd. 701 Tainan Taiwan
| | - Hua‐Fen Hsu
- Department of ChemistryNational Cheng Kung University, No. 1 University Rd. 701 Tainan Taiwan
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46
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Suga T, Shimazu S, Ukaji Y. Low-Valent Titanium-Mediated Radical Conjugate Addition Using Benzyl Alcohols as Benzyl Radical Sources. Org Lett 2018; 20:5389-5392. [DOI: 10.1021/acs.orglett.8b02305] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Takuya Suga
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
| | - Shoma Shimazu
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
| | - Yutaka Ukaji
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
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47
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Yeung D, Penafiel J, Zijlstra HS, McIndoe JS. Oxidation of Titanocene(III): The Deceptive Simplicity of a Color Change. Inorg Chem 2017; 57:457-461. [DOI: 10.1021/acs.inorgchem.7b02705] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Darien Yeung
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Johanne Penafiel
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Harmen S. Zijlstra
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
| | - J. Scott McIndoe
- Department of Chemistry, University of Victoria, PO Box 1700
STN CSC, Victoria, BC V8W 2Y2, Canada
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48
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Bandeira NAG, Veiros LF, Bo C. Hydrogen Generation via Activation of X-H Bonds in Ammonia and Water by an Mo I
Complex. ChemistrySelect 2017. [DOI: 10.1002/slct.201701801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Nuno A. G. Bandeira
- Institute of Chemical Research of Catalonia (ICIQ); Barcelona Institute of Technology (BIST); 16 - Av. Països Catalans 43007 Tarragona Spain
- Centro de Química Estrutural; Instituto Superior Técnico; Universidade de Lisboa; Av. Rovisco Pais 1 1049-001 Lisboa Portugal
- Centro de Química e Bioquímica; Faculdade de Ciências; Universidade de Lisboa; Campo Grande 1749-016 Lisboa Portugal
| | - Luís F. Veiros
- Centro de Química Estrutural; Instituto Superior Técnico; Universidade de Lisboa; Av. Rovisco Pais 1 1049-001 Lisboa Portugal
| | - Carles Bo
- Institute of Chemical Research of Catalonia (ICIQ); Barcelona Institute of Technology (BIST); 16 - Av. Països Catalans 43007 Tarragona Spain
- Departament de Química Física i Inorgànica; Universitat Rovira i Virgili; Av. Marcel.lí Domingo, s/n 43007 Tarragona Spain
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49
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Botubol-Ares J, Hanson JR, Hernández-Galán R, Collado IG. Mild Epoxidation of Allylic Alcohols Catalyzed by Titanium(III) Complexes: Selectivity and Mechanism. ACS OMEGA 2017; 2:3083-3090. [PMID: 31457640 PMCID: PMC6641598 DOI: 10.1021/acsomega.7b00386] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/13/2017] [Indexed: 05/16/2023]
Abstract
A novel methodology for the epoxidation of a broad range of primary, secondary, and tertiary allylic alcohols is described using tert-butyl hydroperoxide as oxidant and Ti(III) species generated by reduction of Ti(IV) complexes, with manganese (0) in 1,4-dioxane under mild reaction conditions. The reaction proceeded with wide substrate scope and high chemo- and diastereoselectivity. A mechanistic pathway for the reaction is also discussed.
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Affiliation(s)
- José
Manuel Botubol-Ares
- Departamento
de Química Orgánica, Facultad de Ciencias, Instituto
de Biomoléculas, Universidad de Cádiz, Campus Universitario Puerto Real
s/n, 11510 Puerto
Real, Cádiz, Spain
| | - James R. Hanson
- Department
of Chemistry, University of Sussex, Brighton, Sussex BN1 9QJ, U.K.
| | - Rosario Hernández-Galán
- Departamento
de Química Orgánica, Facultad de Ciencias, Instituto
de Biomoléculas, Universidad de Cádiz, Campus Universitario Puerto Real
s/n, 11510 Puerto
Real, Cádiz, Spain
| | - Isidro G. Collado
- Departamento
de Química Orgánica, Facultad de Ciencias, Instituto
de Biomoléculas, Universidad de Cádiz, Campus Universitario Puerto Real
s/n, 11510 Puerto
Real, Cádiz, Spain
- E-mail:
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50
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Bezdek MJ, Guo S, Chirik PJ. Coordination-induced weakening of ammonia, water, and hydrazine X-H bonds in a molybdenum complex. Science 2017; 354:730-733. [PMID: 27846601 DOI: 10.1126/science.aag0246] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 07/17/2016] [Accepted: 09/13/2016] [Indexed: 01/20/2023]
Abstract
Although scores of transition metal complexes incorporating ammonia or water ligands have been characterized over the past century, little is known about how coordination influences the strength of the nitrogen-hydrogen and oxygen-hydrogen bonds. Here we report the synthesis of a molybdenum ammonia complex supported by terpyridine and phosphine ligands that lowers the nitrogen-hydrogen bond dissociation free energy from 99.5 (gas phase) to an experimentally measured value of 45.8 kilocalories per mole (agreeing closely with a value of 45.1 kilocalories per mole calculated by density functional theory). This bond weakening enables spontaneous dihydrogen evolution upon gentle heating, as well as the hydrogenation of styrene. Analogous molybdenum complexes promote dihydrogen evolution from coordinated water and hydrazine. Electrochemical and theoretical studies elucidate the contributions of metal redox potential and ammonia acidity to this effect.
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Affiliation(s)
- Máté J Bezdek
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Sheng Guo
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Paul J Chirik
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
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