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Bühler J, Muntwyler A, Roithmeyer H, Adams P, Besmer ML, Blacque O, Tilley SD. Immobilised Ruthenium Complexes for the Electrooxidation of 5-Hydroxymethylfurfural. Chemistry 2024; 30:e202304181. [PMID: 38285807 DOI: 10.1002/chem.202304181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/26/2024] [Accepted: 01/29/2024] [Indexed: 01/31/2024]
Abstract
Abundantly available biomass-based platform chemicals, including 5-hydroxymethylfurfural (HMF), are essential stepping stones in steering the chemical industry away from fossil fuels. The efficient catalytic oxidation of HMF to its diacid derivative, 2,5-furandicarboxylic acid (FDCA), is a promising research area with potential applications in the polymer industry. Currently, the most encouraging approaches are based on solid-state catalysts and are often conducted in basic aqueous media, conditions where HMF oxidation competes with its decomposition. Efficient molecular catalysts are practically unknown for this reaction. In this study, we report on the synthesis and electrocatalysis of surface-bound molecular ruthenium complexes for the transformation of HMF to FDCA under acidic conditions. Catalyst immobilisation on mesoporous indium tin oxide electrodes is achieved through the incorporation of phosphonic acid anchoring groups. Screening experiments with HMF and further reaction intermediates revealed the catalytic route and bottlenecks in the catalytic synthesis of FDCA. Utilising these immobilised electrocatalysts, FDCA yields of up to 85 % and faradaic efficiencies of 91 % were achieved, without any indication of substrate decomposition. Surface analysis by X-ray photoelectron spectroscopy (XPS) post-electrocatalysis unveiled the desorption of the catalyst from the electrode surface as a limiting factor in terms of catalytic performance.
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Affiliation(s)
- Jan Bühler
- Department of Chemistry, University of Zurich Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Alissa Muntwyler
- Department of Chemistry, University of Zurich Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Helena Roithmeyer
- Department of Chemistry, University of Zurich Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Pardis Adams
- Department of Chemistry, University of Zurich Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Manuel Luca Besmer
- Department of Chemistry, University of Zurich Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Olivier Blacque
- Department of Chemistry, University of Zurich Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - S David Tilley
- Department of Chemistry, University of Zurich Winterthurerstrasse 190, 8057, Zurich, Switzerland
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2
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Chen J, Song W, Yao J, Wu Z, Lee YM, Wang Y, Nam W, Wang B. Hydrogen Bonding-Assisted and Nonheme Manganese-Catalyzed Remote Hydroxylation of C-H Bonds in Nitrogen-Containing Molecules. J Am Chem Soc 2023; 145:5456-5466. [PMID: 36811463 DOI: 10.1021/jacs.2c13832] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The development of catalytic systems capable of oxygenating unactivated C-H bonds with excellent site-selectivity and functional group tolerance under mild conditions remains a challenge. Inspired by the secondary coordination sphere (SCS) hydrogen bonding in metallooxygenases, reported herein is an SCS solvent hydrogen bonding strategy that employs 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as a strong hydrogen bond donor solvent to enable remote C-H hydroxylation in the presence of basic aza-heteroaromatic rings with a low loading of a readily available and inexpensive manganese complex as a catalyst and hydrogen peroxide as a terminal oxidant. We demonstrate that this strategy represents a promising compliment to the current state-of-the-art protection approaches that rely on precomplexation with strong Lewis and/or Brønsted acids. Mechanistic studies with experimental and theoretical approaches reveal the existence of a strong hydrogen bonding between the nitrogen-containing substrate and HFIP, which prevents the catalyst deactivation by nitrogen binding and deactivates the basic nitrogen atom toward oxygen atom transfer and the α-C-H bonds adjacent to the nitrogen center toward H-atom abstraction. Moreover, the hydrogen bonding exerted by HFIP has also been demonstrated not only to facilitate the O-O bond heterolytic cleavage of a putative MnIII-OOH precursor to generate MnV(O)(OC(O)CH2Br) as an active oxidant but also to affect the stability and the activity of MnV(O)(OC(O)CH2Br).
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Affiliation(s)
- Jie Chen
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China
| | - Wenxun Song
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China
| | - Jinping Yao
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China
| | - Zhimin Wu
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yong Wang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Bin Wang
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China
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3
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Vereshchuk N, Gil-Sepulcre M, Ghaderian A, Holub J, Gimbert-Suriñach C, Llobet A. Metamorphic oxygen-evolving molecular Ru and Ir catalysts. Chem Soc Rev 2023; 52:196-211. [PMID: 36459110 DOI: 10.1039/d2cs00463a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Today sustainable and clean energy conversion strategies are based on sunlight and the use of water as a source of protons and electrons, in a similar manner as it happens in Photosystem II. To achieve this, the charge separation state induced by light has to be capable of oxidising water by 4 protons and 4 electrons and generating molecular oxygen. This oxidation occurs by the intermediacy of a catalyst capable of finding low-energy pathways via proton-coupled electron transfer steps. The high energy involved in the thermodynamics of water oxidation reaction, coupled with its mechanistic complexity, is responsible for the difficulty of discovering efficient and oxidatively robust molecules capable of achieving such a challenging task. A significant number of Ru coordination complexes have been identified as water oxidation catalysts (WOCs) and are among the best understood from a mechanistic perspective. In this review, we describe the catalytic performance of these complexes and focus our attention on the factors that influence their performance during catalysis, especially in cases where a detailed mechanistic investigation has been carried out. The collective information extracted from all the catalysts studied allows one to identify the key features that govern the complex chemistry associated with the catalytic water oxidation reaction. This includes the stability of trans-O-Ru-O groups, the change in coordination number from CN6 to CN7 at Ru high oxidation states, the ligand flexibility, the capacity to undergo intramolecular proton transfer, the bond strain, the axial ligand substitution, and supramolecular effects. Overall, combining all this information generates a coherent view of this complex chemistry.
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Affiliation(s)
- Nataliia Vereshchuk
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007 Tarragona, Spain. .,Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo s/n, 43007 Tarragona, Spain
| | - Marcos Gil-Sepulcre
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007 Tarragona, Spain.
| | - Abolfazl Ghaderian
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007 Tarragona, Spain. .,Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo s/n, 43007 Tarragona, Spain
| | - Jan Holub
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007 Tarragona, Spain. .,Department of Inorganic Chemistry, University of Chemistry and Technology, Prague, CZ-16628 Prague, Czech Republic
| | - Carolina Gimbert-Suriñach
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007 Tarragona, Spain. .,Departament de Química, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain
| | - Antoni Llobet
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Avda. Països Catalans 16, 43007 Tarragona, Spain. .,Departament de Química, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain
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4
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Recent progress in oxidation chemistry of high-valent ruthenium-oxo and osmium-oxo complexes and related species. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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5
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Ranu B, Egorov I, Mukherjee A, Santra S, Kopchuk D, Kovalev I, Zyryanov G, Majee A, Chupakhin O, Liu Y. Mechanochemically Induced Cross Dehydrogenative Coupling Reactions under Ball Milling. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202200296] [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)
| | - Ilya Egorov
- Ural Federal University named after the first President of Russia B N Yeltsin RUSSIAN FEDERATION
| | - Anindita Mukherjee
- Ural'skij federal'nyj universitet imeni pervogo Prezidenta Rossii B N El'cina RUSSIAN FEDERATION
| | - Sougata Santra
- Ural Federal University named after the first President of Russia B N Yeltsin RUSSIAN FEDERATION
| | - Dmitry Kopchuk
- Institute of Organic Synthesis UB RAS RUSSIAN FEDERATION
| | | | - Grigory Zyryanov
- Ural Federal University named after the first President of Russia B N Yeltsin RUSSIAN FEDERATION
| | | | - Oleg Chupakhin
- Ural Federal University named after the first President of Russia B N Yeltsin RUSSIAN FEDERATION
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Bühler J, Zurflüh J, Siol S, Blacque O, Sévery L, Tilley D. Electrochemical Ruthenium-Catalysed C–H Activation in Water Through Heterogenization of a Molecular Catalyst. Catal Sci Technol 2022. [DOI: 10.1039/d1cy01999f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Efficient catalytic oxidative C–H activation of organic substrates remains an important challenge in synthetic chemistry. Here, we show that the combination of a transition metal catalyst, surface immobilisation and an...
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7
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Jin JC, Liu XY, Yang GP, Hou L, Wang YY. A microporous anionic metal–organic framework for aqueous encapsulation and highly reversible sensitization of light-emitting Tb 3+ ions. NEW J CHEM 2022. [DOI: 10.1039/d1nj02418c] [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
An anionic porous material can serve as both a host and an antenna for protecting and sensitizing extra-framework light-emitting Eu3+/Tb3+ ions. The Tb3+ uptake and release is a reversible process and the cationic Tb3+ can be gradually released.
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Affiliation(s)
- J. C. Jin
- Address Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi’an 710069, P. R. China
- Anhui Provincial Laboratory of Biomimetic Sensor and Detecting Technology, West Anhui University, Anhui 237012, P. R. China
| | - X. Y. Liu
- Address Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi’an 710069, P. R. China
- State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, Yinchuan 750021, P. R. China
| | - G. P. Yang
- Address Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi’an 710069, P. R. China
| | - L. Hou
- Address Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi’an 710069, P. R. China
| | - Y. Y. Wang
- Address Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi’an 710069, P. R. China
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8
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Sun J, Yin Y, Li W, Jin O, Na N. CHEMICAL REACTION MONITORING BY AMBIENT MASS SPECTROMETRY. MASS SPECTROMETRY REVIEWS 2022; 41:70-99. [PMID: 33259644 DOI: 10.1002/mas.21668] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/16/2020] [Accepted: 10/22/2020] [Indexed: 06/12/2023]
Abstract
Chemical reactions conducted in different media (liquid phase, gas phase, or surface) drive developments of versatile techniques for the detection of intermediates and prediction of reasonable reaction pathways. Without sample pretreatment, ambient mass spectrometry (AMS) has been applied to obtain structural information of reactive molecules that differ in polarity and molecular weight. Commercial ion sources (e.g., electrospray ionization, atmospheric pressure chemical ionization, and direct analysis in real-time) have been reported to monitor substrates and products by offline reaction examination. While the interception or characterization of reactive intermediates with short lifetime are still limited by the offline modes. Notably, online ionization technologies, with high tolerance to salt, buffer, and pH, can achieve direct sampling and ionization of on-going reactions conducted in different media (e.g., liquid phase, gas phase, or surface). Therefore, short-lived intermediates could be captured at unprecedented timescales, and the reaction dynamics could be studied for mechanism examinations without sample pretreatments. In this review, via various AMS methods, chemical reaction monitoring and mechanism elucidation for different classifications of reactions have been reviewed. The developments and advances of common ionization methods for offline reaction monitoring will also be highlighted.
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Affiliation(s)
- Jianghui Sun
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Yiyan Yin
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Weixiang Li
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Ouyang Jin
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Na Na
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
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9
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Griffin JD, Vogt DB, Du Bois J, Sigman MS. Mechanistic Guidance Leads to Enhanced Site-Selectivity in C–H Oxidation Reactions Catalyzed by Ruthenium bis(Bipyridine) Complexes. ACS Catal 2021. [DOI: 10.1021/acscatal.1c02593] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Jeremy D. Griffin
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - David B. Vogt
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - J. Du Bois
- Department of Chemistry, Stanford University, 337 Campus Drive, Stanford, California 94305, United States
| | - Matthew S. Sigman
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
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10
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Li Z, Wang Z, Chekshin N, Qian S, Qiao JX, Cheng PT, Yeung KS, Ewing WR, Yu JQ. A tautomeric ligand enables directed C‒H hydroxylation with molecular oxygen. Science 2021; 372:1452-1457. [PMID: 34840353 DOI: 10.1126/science.abg2362] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hydroxylation of aryl carbon-hydrogen bonds with transition metal catalysts has proven challenging when oxygen is used as the oxidant. Here, we report a palladium complex bearing a bidentate pyridine/pyridone ligand that efficiently catalyzes this reaction at ring positions adjacent to carboxylic acids. Infrared, x-ray, and computational analysis support a possible role of ligand tautomerization from mono-anionic (L,X) to neutral (L,L) coordination in the catalytic cycle of aerobic carbon-hydrogen hydroxylation reaction. The conventional site selectivity dictated by heterocycles is overturned by this catalyst, thus allowing late-stage modification of compounds of pharmaceutical interest at previously inaccessible sites.
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Affiliation(s)
- Zhen Li
- The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Zhen Wang
- The Scripps Research Institute, La Jolla, CA 92037, USA
| | | | - Shaoqun Qian
- The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jennifer X Qiao
- Discovery Chemistry, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Peter T Cheng
- Discovery Chemistry, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Kap-Sun Yeung
- Bristol-Myers Squibb Research and Development, Cambridge, MA 02142, USA
| | - William R Ewing
- Discovery Chemistry, Bristol-Myers Squibb, Princeton, NJ 08543, USA
| | - Jin-Quan Yu
- The Scripps Research Institute, La Jolla, CA 92037, USA
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11
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Robinson SG, Mack JBC, Alektiar SN, Du Bois J, Sigman MS. Electrochemical Ruthenium-Catalyzed C-H Hydroxylation of Amine Derivatives in Aqueous Acid. Org Lett 2020; 22:7060-7063. [PMID: 32419465 DOI: 10.1021/acs.orglett.0c01313] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The development of an electrochemically driven, ruthenium-catalyzed C-H hydroxylation reaction of amine-derived substrates bearing tertiary C-H bonds is described. The reaction is performed under constant current electrolysis in a divided cell to afford alcohol products in yields comparable to those of our previously reported process, which requires the use of stoichiometric H5IO6 for catalytic turnover. With aqueous acid as solvent, the cathodic electrode reaction simply involves the reduction of protons to evolve hydrogen gas. The optimized protocol offers a convenient, efficient, and atom-economical method for sp3-C-H bond oxidation.
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Affiliation(s)
- Sophia G Robinson
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - James B C Mack
- Department of Chemistry, Stanford University, 337 Campus Drive, Stanford, California 94305, United States
| | - Sara N Alektiar
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - J Du Bois
- Department of Chemistry, Stanford University, 337 Campus Drive, Stanford, California 94305, United States
| | - Matthew S Sigman
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
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12
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Doiuchi D, Nakamura T, Hayashi H, Uchida T. Non‐Heme‐Type Ruthenium Catalyzed Chemo‐ and Site‐Selective C−H Oxidation. Chem Asian J 2020; 15:762-765. [DOI: 10.1002/asia.202000134] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/17/2020] [Indexed: 01/17/2023]
Affiliation(s)
- Daiki Doiuchi
- Department of Chemistry Graduate School of ScienceKyushu University 744, Motooka, Nishi-ku Fukuoka 819-0395 Japan
| | - Tatsuya Nakamura
- Department of Chemistry Graduate School of ScienceKyushu University 744, Motooka, Nishi-ku Fukuoka 819-0395 Japan
| | - Hiroki Hayashi
- Faculty of Arts and ScienceKyushu University 744, Motooka, Nishi-ku Fukuoka 819-0395 Japan
| | - Tatsuya Uchida
- Faculty of Arts and ScienceKyushu University 744, Motooka, Nishi-ku Fukuoka 819-0395 Japan
- International Institute for Carbon-Neutral Energy Research (WPI−I2CNER)Kyushu University 744, Motooka, Nishi-ku Fukuoka 819-0395 Japan
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13
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Robinson SG, Sigman MS. Integrating Electrochemical and Statistical Analysis Tools for Molecular Design and Mechanistic Understanding. Acc Chem Res 2020; 53:289-299. [PMID: 31920070 DOI: 10.1021/acs.accounts.9b00527] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Medicinal chemistry campaigns set the foundation for streamlined molecular design strategies through the development of quantitative structure-activity models. Our group's enduring underlying interest in reaction mechanism propelled our adaption of a similar strategy to unite mechanistic interrogation and catalyst optimization by relating reaction outputs to molecular descriptors. Through collaborative opportunities, we have recently expanded these predictive statistical modeling tools to electrocatalysis and the design of redox-active organic molecules for application as electrolytes in nonaqueous redox flow batteries. Utilizing small, strategically designed data sets for a given core structure, we develop predictive statistical models that enable rapid virtual screening campaigns to identify analogues with enhanced properties. This process relates structural parameters to the output of interest, providing insight into the structural features that influence the output under study. Furthermore, the weighting of the coefficients for each parameter in the model can furnish mechanistic insight. Such a synergistic implementation of experimental and computational tools for mechanistic insight provides a means of forecasting properties of analogues without necessitating the synthesis and analysis of each molecule of interest. Through collaborative efforts, we have demonstrated the effectiveness of these tools for predicting diverse outputs such as stability, redox potential, and nonaqueous solubility. In this Account, we outline our entry into the field of organic electrochemistry and the implementation of statistical modeling tools for designing organic electrolytes. Through these projects we were exposed to the power of electrochemical techniques as a mechanistic tool, which has provided access to critical information that would otherwise be difficult to obtain. Utilizing electroanalytical techniques, we have quantified the rates of disproportionation of a variety of cobalt complexes and developed statistical models that provide critical insight into understanding of fundamental processes involved in the disproportionation of organometallic complexes. Electroanalytical tools have also been effective in elucidating the active catalyst oxidation state in different catalytic organometallic systems for C-H functionalization. Thus, our foray into electrolyte design and electrocatalysis, in which the statistical modeling tools developed for mechanistic insight were applied in a new context, came full circle to the core foundation of our group: mechanistic understanding.
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Affiliation(s)
- Sophia G. Robinson
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Matthew S. Sigman
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
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14
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Chen X, Wang Q, Shen H, Li G, Yang YF, She YB. Mechanism and stereoselectivity of benzylic C-H hydroxylation by Ru-porphyrin: a computational study. Org Biomol Chem 2020; 18:346-352. [PMID: 31845954 DOI: 10.1039/c9ob02415h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The mechanism and origin of the stereoselectivity of asymmetric benzylic C-H hydroxylation by Ru-porphyrin were elucidated with density functional theory calculations. The reaction proceeds via a hydrogen-atom abstraction/oxygen-rebound pathway, wherein a high-valent ruthenium-oxo species abstracts a hydrogen atom from ethylbenzene to generate a radical pair intermediate, followed by the oxygen-rebound process to form 1-phenylethanol. The hydrogen-atom abstraction step is the rate- and stereoselectivity-determining step. Based on the mechanistic model, the computed stereoselectivity is in agreement with the experimental observations. Analysis of the distortion/interaction model suggests that stereoselectivity is determined by both the distortion energy of the ethylbenzene and the interaction energy between the ethylbenzene and the chiral Ru-porphyrin. The steric repulsion between the phenyl group of ethylbenzene and the bulky substituent of Ru-porphyrin is the leading cause of chiral induction.
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Affiliation(s)
- Xiahe Chen
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China.
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15
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Amtawong J, Balcells D, Wilcoxen J, Handford RC, Biggins N, Nguyen AI, Britt RD, Tilley TD. Isolation and Study of Ruthenium-Cobalt Oxo Cubanes Bearing a High-Valent, Terminal Ru V-Oxo with Significant Oxyl Radical Character. J Am Chem Soc 2019; 141:19859-19869. [PMID: 31697896 DOI: 10.1021/jacs.9b10320] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
High-valent RuV-oxo intermediates have long been proposed in catalytic oxidation chemistry, but investigations into their electronic and chemical properties have been limited due to their reactive nature and rarity. The incorporation of Ru into the [Co3O4] subcluster via the single-step assembly reaction of CoII(OAc)2(H2O)4 (OAc = acetate), perruthenate (RuO4-), and pyridine (py) yielded an unprecedented Ru(O)Co3(μ3-O)4(OAc)4(py)3 cubane featuring an isolable, yet reactive, RuV-oxo moiety. EPR, ENDOR, and DFT studies reveal a valence-localized [RuV(S = 1/2)CoIII3(S = 0)O4] configuration and non-negligible covalency in the cubane core. Significant oxyl radical character in the RuV-oxo unit is experimentally demonstrated by radical coupling reactions between the oxo cubane and both 2,4,6-tri-tert-butylphenoxyl and trityl radicals. The oxo cubane oxidizes organic substrates and, notably, reacts with water to form an isolable μ-oxo bis-cubane complex [(py)3(OAc)4Co3(μ3-O)4Ru]-O-[RuCo3(μ3-O)4(OAc)4(py)3]. Redox activity of the RuV-oxo fragment is easily tuned by the electron-donating ability of the distal pyridyl ligand set at the Co sites demonstrating strong electronic communication throughout the entire cubane cluster. Natural bond orbital calculations reveal cooperative orbital interactions of the [Co3O4] unit in supporting the RuV-oxo moiety via a strong π-electron donation.
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Affiliation(s)
- Jaruwan Amtawong
- Department of Chemistry , University of California at Berkeley , Berkeley , California 94720-1460 , United States
| | - David Balcells
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry , University of Oslo , P.O. Box 1033, Blindern, 0315 Oslo , Norway
| | - Jarett Wilcoxen
- Department of Chemistry , University of California , Davis , California 95616 , United States
| | - Rex C Handford
- Department of Chemistry , University of California at Berkeley , Berkeley , California 94720-1460 , United States
| | - Naomi Biggins
- Department of Chemistry , University of California at Berkeley , Berkeley , California 94720-1460 , United States
| | - Andy I Nguyen
- Department of Chemistry , University of California at Berkeley , Berkeley , California 94720-1460 , United States.,Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - R David Britt
- Department of Chemistry , University of California , Davis , California 95616 , United States
| | - T Don Tilley
- Department of Chemistry , University of California at Berkeley , Berkeley , California 94720-1460 , United States.,Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
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Sandford C, Edwards MA, Klunder KJ, Hickey DP, Li M, Barman K, Sigman MS, White HS, Minteer SD. A synthetic chemist's guide to electroanalytical tools for studying reaction mechanisms. Chem Sci 2019; 10:6404-6422. [PMID: 31367303 PMCID: PMC6615219 DOI: 10.1039/c9sc01545k] [Citation(s) in RCA: 180] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/23/2019] [Indexed: 12/19/2022] Open
Abstract
Monitoring reactive intermediates can provide vital information in the study of synthetic reaction mechanisms, enabling the design of new catalysts and methods. Many synthetic transformations are centred on the alteration of oxidation states, but these redox processes frequently pass through intermediates with short life-times, making their study challenging. A variety of electroanalytical tools can be utilised to investigate these redox-active intermediates: from voltammetry to in situ spectroelectrochemistry and scanning electrochemical microscopy. This perspective provides an overview of these tools, with examples of both electrochemically-initiated processes and monitoring redox-active intermediates formed chemically in solution. The article is designed to introduce synthetic organic and organometallic chemists to electroanalytical techniques and their use in probing key mechanistic questions.
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Affiliation(s)
- Christopher Sandford
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , USA . ; ;
| | - Martin A Edwards
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , USA . ; ;
| | - Kevin J Klunder
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , USA . ; ;
| | - David P Hickey
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , USA . ; ;
| | - Min Li
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , USA . ; ;
| | - Koushik Barman
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , USA . ; ;
| | - Matthew S Sigman
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , USA . ; ;
| | - Henry S White
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , USA . ; ;
| | - Shelley D Minteer
- Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112 , USA . ; ;
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