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Wang J, Jing X, Yang Y, Xu B, Jia R, Duan C. Enzymatic Activation and Continuous Electrochemical Production of Methane from Dilute CO 2 Sources with a Self-Healing Capsule. J Am Chem Soc 2024; 146:19951-19961. [PMID: 38963753 DOI: 10.1021/jacs.4c03367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/06/2024]
Abstract
Converting dilute CO2 source into value-added chemicals and fuels is a promising route to reduce fossil fuel consumption and greenhouse gas emission, but integrating electrocatalysis with CO2 capture still faced marked challenges. Herein, we show that a self-healing metal-organic macrocycle functionalized as an electrochemical catalyst to selectively produce methane from flue gas and air with the lowest applied potential so far (0.06 V vs reversible hydrogen electrode, RHE) through an enzymatic activation fashion. The capsule emulates the enzyme' pocket to abstract one in situ-formed CO2-adduct molecule with the commercial amino alcohols, forming an easy-to-reduce substrate-involving clathrate to combine the CO2 capture with electroreduction for a thorough CO2 reduction. We find that the self-healing system exhibited enzymatic kinetics for the first time with the Michaelis-Menten mechanism in the electrochemical reduction of CO2 and maintained a methane Faraday efficiency (FE) of 74.24% with a selectivity of over 99% for continuous operation over 200 h. A consecutive working lab at 50 mA·cm-2, in an eleven-for-one (10 h working and 1 h healing) electrolysis manner, gives a methane turnover number (TON) of more than 10,000 within 100 h. The integrated electrolysis with CO2 capture facilitates the thorough reduction of flue gas (ca. 13.0% of CO2) and first time of air (ca. 400 ppm of CO2 to 42.7 mL CH4 from 1.0 m3 air). The new self-healing strategy of molecular electrocatalyst with an enzymatic activation manner and anodic shifting of the applied potentials provided a departure from the existing electrochemical catalytic techniques.
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Affiliation(s)
- Jinfeng Wang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Xu Jing
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Yang Yang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Baijie Xu
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Ruiming Jia
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Chunying Duan
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
- State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210008, China
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2
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van der Zee LJC, Hofman J, van Gaalen JM, Slootweg JC. Mechanistic studies on single-electron transfer in frustrated Lewis pairs and its application to main-group chemistry. Chem Soc Rev 2024; 53:4862-4876. [PMID: 38623621 PMCID: PMC11104263 DOI: 10.1039/d4cs00185k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Indexed: 04/17/2024]
Abstract
Advances in the field of frustrated Lewis pair (FLP) chemistry have led to the discovery of radical pairs, obtained by a single-electron transfer (SET) from the Lewis base to the Lewis acid. Radical pairs are intriguing for their potential to enable cooperative activation of challenging substrates (e.g., CH4, N2) in a homolytic fashion, as well as the exploration of novel radical reactions. In this review, we will cover the two known mechanisms of SET in FLPs-thermal and photoinduced-along with methods (i.e., CV, DFT, UV-vis) to predict the mechanism and to characterise the involved electron donors and acceptors. Furthermore, the available techniques (i.e., EPR, UV-vis, transient absorption spectroscopy) for studying the corresponding radical pairs will be discussed. Initially, two model systems (PMes3/CPh3+ and PMes3/B(C6F5)3) will be reviewed to highlight the difference between a thermal and a photoinduced SET mechanism. Additionally, three cases are analysed to provide further tools and insights into characterizing electron donors and acceptors, and the associated radical pairs. Firstly, a thermal SET process between LiHMDS and [TEMPO][BF4] is discussed. Next, the influence of Lewis acid complexation on the electron acceptor will be highlighted to facilitate a SET between (pBrPh)3N and TCNQ. Finally, an analysis of sulfonium salts as electron acceptors will demonstrate how to manage systems with rapidly decomposing radical species. This framework equips the reader with an expanded array of tools for both predicting and characterizing SET events within FLP chemistry, thereby enabling its extension and application to the broader domain of main-group (photo)redox chemistry.
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Affiliation(s)
- Lars J C van der Zee
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, PO box 94157, 1090 GD Amsterdam, The Netherlands.
| | - Jelle Hofman
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, PO box 94157, 1090 GD Amsterdam, The Netherlands.
| | - Joost M van Gaalen
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, PO box 94157, 1090 GD Amsterdam, The Netherlands.
| | - J Chris Slootweg
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, PO box 94157, 1090 GD Amsterdam, The Netherlands.
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3
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Arman A, Sağlam Ş, Üzer A, Apak R. A novel electrochemical sensor based on phosphate-stabilized poly-caffeic acid film in combination with graphene nanosheets for sensitive determination of nitro-aromatic energetic materials. Talanta 2024; 266:125098. [PMID: 37639871 DOI: 10.1016/j.talanta.2023.125098] [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: 01/23/2023] [Revised: 07/31/2023] [Accepted: 08/18/2023] [Indexed: 08/31/2023]
Abstract
This work offers a novel approach and sensor electrode for electrocatalytic reduction of nitro-aromatic explosives (NAEs). This sensor was created by combining electrochemically reduced graphene nanosheets (GNSs) -through cyclic voltammetric reduction of a graphene oxide colloidal solution- with phosphate-stabilized poly-caffeic acid (pCAF) film-modified glassy carbon electrode (GCE). The poly-caffeic acid-modified nonconductive electrode was stabilized with a H2PO4-/HPO42- phosphate buffer at pH 7 and made conductive. The novel electrode, called phosphate stabilized-GC/GNSs/pCAF, was characterized by electrochemical methods and scanning electron microscopy (SEM). The sensor exhibited high performance for trinitrotoluene (TNT) detection with a linear response between 50 and 500 μg L- 1 and a detection limit of 6 μg L-1. In addition to TNT, precise determinations of NAEs such as 2,4-dinitrotoluene (2,4-DNT), tetryl (2,4,6-trinitrophenyl methyl nitramine), trinitro phenol (TNP or picric acid; PA), 2,4-dinitrophenol (2,4-DNP), and 4-amino dinitrotoluene (4A-DNT, an aerobic bacterial degradation product of TNT) were made using the developed sensor electrode and DPV technique. Simultaneous quantification of TNT and DNT was performed with the aid of a computational technique known as multiple linear regression (MLR). The optimized electrode was resistant to interference effects. Satisfactory results on real samples were obtained by applying the modified electrode to the determination of TNT, tetryl, and TNP in contaminated soil. The validation of the proposed method was made against a literature LC-MS/MS method. A statistical comparison of the obtained results was provided using F- and Student's t-tests.
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Affiliation(s)
- Aysu Arman
- Institute of Graduate Studies, Chemistry Department, Istanbul University-Cerrahpaşa, Avcılar, Istanbul, Turkey; Engineering Faculty, Chemistry Department, Istanbul University-Cerrahpaşa, Avcılar, Istanbul, Turkey
| | - Şener Sağlam
- Engineering Faculty, Chemistry Department, Istanbul University-Cerrahpaşa, Avcılar, Istanbul, Turkey
| | - Ayşem Üzer
- Engineering Faculty, Chemistry Department, Istanbul University-Cerrahpaşa, Avcılar, Istanbul, Turkey
| | - Reşat Apak
- Engineering Faculty, Chemistry Department, Istanbul University-Cerrahpaşa, Avcılar, Istanbul, Turkey; Turkish Academy of Sciences (TUBA), Bayraktar Neighborhood, Vedat Dalokay St. No:112, 06670, Çankaya, Ankara, Turkey.
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4
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van der Zee LJ, Pahar S, Richards E, Melen RL, Slootweg JC. Insights into Single-Electron-Transfer Processes in Frustrated Lewis Pair Chemistry and Related Donor-Acceptor Systems in Main Group Chemistry. Chem Rev 2023; 123:9653-9675. [PMID: 37431868 PMCID: PMC10416219 DOI: 10.1021/acs.chemrev.3c00217] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Indexed: 07/12/2023]
Abstract
The activation and utilization of substrates mediated by Frustrated Lewis Pairs (FLPs) was initially believed to occur solely via a two-electron, cooperative mechanism. More recently, the occurrence of a single-electron transfer (SET) from the Lewis base to the Lewis acid was observed, indicating that mechanisms that proceed via one-electron-transfer processes are also feasible. As such, SET in FLP systems leads to the formation of radical ion pairs, which have recently been more frequently observed. In this review, we aim to discuss the seminal findings regarding the recently established insights into the SET processes in FLP chemistry as well as highlight examples of this radical formation process. In addition, applications of reported main group radicals will also be reviewed and discussed in the context of the understanding of SET processes in FLP systems.
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Affiliation(s)
- Lars J.
C. van der Zee
- Van
’t Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
| | - Sanjukta Pahar
- Cardiff
Catalysis Institute, Cardiff University, Translational Research Hub, Maindy
Road, Cathays, Cardiff, CF24 4HQ Wales, United Kingdom
| | - Emma Richards
- Cardiff
Catalysis Institute, Cardiff University, Translational Research Hub, Maindy
Road, Cathays, Cardiff, CF24 4HQ Wales, United Kingdom
| | - Rebecca L. Melen
- Cardiff
Catalysis Institute, Cardiff University, Translational Research Hub, Maindy
Road, Cathays, Cardiff, CF24 4HQ Wales, United Kingdom
| | - J. Chris Slootweg
- Van
’t Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
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5
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Miller JL, Lawrence JMIA, Rodriguez Del Rey FO, Floreancig PE. Synthetic applications of hydride abstraction reactions by organic oxidants. Chem Soc Rev 2022; 51:5660-5690. [PMID: 35712818 DOI: 10.1039/d1cs01169c] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Carbon-hydrogen bond functionalizations provide an attractive method for streamlining organic synthesis, and many strategies have been developed for conducting these transformations. Hydride-abstracting reactions have emerged as extremely effective methods for oxidative bond-forming processes due to their mild reaction conditions and high chemoselectivity. This review will predominantly focus on the mechanism, reaction development, natural product synthesis applications, approaches to catalysis, and use in enantioselective processes for hydride abstractions by quinone, oxoammonium ion, and carbocation oxidants. These are the most commonly employed hydride-abstracting agents, but recent efforts illustrate the potential for weaker ketone and triaryl borane oxidants, which will be covered at the end of the review.
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Affiliation(s)
- Jenna L Miller
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA.
| | - Jean-Marc I A Lawrence
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA.
| | | | - Paul E Floreancig
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA.
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6
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Proton coupled electron transport of pH sensitive coumarin based ruthenium(II) complex: A functional mimic of photosystem II. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2021. [DOI: 10.1016/j.jpap.2021.100057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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7
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Smith DK. Exploring the Role of H-Bonding in Organic Electrochemistry - From Supramolecular Applications to Mechanistic Investigations. CHEM REC 2021; 21:2488-2501. [PMID: 34487420 DOI: 10.1002/tcr.202100186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/22/2021] [Indexed: 11/09/2022]
Abstract
H-bonds can exert a substantial impact on the course of organic electrode reactions due to their ability to stabilize charged intermediates and products formed during these reactions, as well as facilitate proton-coupled electron transfer (PCET) reactions. This has fundamental implications for the mechanism of organic electrode reactions, but also practical impact in supramolecular chemistry and potentially synthetic electrochemistry. My group's main focus has been on the supramolecular applications, using electron transfer to alter the strength of H-bonds to create highly redox-responsive H-bond dimers. Initially we sought to avoid proton transfer because we feared that would lead to irreversible electrochemistry. However, inevitably proton transfer did show up, but, to our surprise, did not lead to irreversible electrochemistry. To explain this, we developed a new mechanism, the "wedge scheme", that shows how H-bonding can facilitate reversible electron and proton transfer. This insight recently led us to a new PCET-based design strategy for the creation of our most highly redox-responsive H-bond dimers yet.
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Affiliation(s)
- Diane K Smith
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Dr, San Diego, CA, 92182, USA
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8
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Walter P, Hübner O, Kaifer E, Himmel HJ. Proton-Coupled Electron Transfer (PCET) with 1,4-Bisguanidino-Benzene Derivatives: Comparative Study and Use in Acid-Initiated C-H Activation. Chemistry 2021; 27:11943-11956. [PMID: 34132428 PMCID: PMC8457230 DOI: 10.1002/chem.202101539] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Indexed: 11/18/2022]
Abstract
Proton‐coupled electron transfer (PCET) is of key importance in modern synthetic chemistry. Redox‐active guanidines were established by our group as valuable alternatives to toxic high‐potential benzoquinones in a variety of different PCET reactions. In this work, the PCET reactivity of a series of 1,4‐bisguanidino‐benzenes varying in their redox potentials and proton affinities is evaluated. The relevant redox and protonation states are fully characterized, and the compounds sorted with respect to their PCET reactivity by comparative PCET experiments supplemented by quantum‐chemical calculations. Depending on the studied reactions, the driving force is either electron transfer or proton transfer; thereby the influence of both processes on the overall reactivity could be assessed. Then, two of the PCET reagents are applied in representative oxidative aryl‐aryl coupling reactions, namely the intramolecular coupling of 3,3’’‐4,4’’‐tetramethoxy‐o‐terphenyl to give the corresponding triphenylene, the intermolecular coupling of N‐ethylcarbazole to give N,N’‐diethyl‐3,3’‐bicarbazole, and in the oxidative lactonization of 2‐[(4‐methoxyphenyl)methyl]‐benzoic acid. Under mild conditions, the reactions proceed fast and efficient. Only small amounts of acid are needed, in clear contrast to the corresponding coupling reactions with traditional high‐potential benzoquinones such as DDQ or chloranil requiring a large excess of a strong acid.
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Affiliation(s)
- Petra Walter
- Inorganic Chemistry, Ruprecht-Karls University of Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Olaf Hübner
- Inorganic Chemistry, Ruprecht-Karls University of Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Elisabeth Kaifer
- Inorganic Chemistry, Ruprecht-Karls University of Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hans-Jörg Himmel
- Inorganic Chemistry, Ruprecht-Karls University of Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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9
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Maskey R, Bendel C, Malzacher J, Greb L. Completing the Redox-Series of Silicon Trisdioxolene: ortho-Quinone and Lewis Superacid Make a Powerful Redox Catalyst. Chemistry 2020; 26:17386-17389. [PMID: 33108014 PMCID: PMC7839739 DOI: 10.1002/chem.202004712] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Indexed: 12/25/2022]
Abstract
Quinones are mild oxidants, the redox potentials of which can be increased by supramolecular interactions. Whereas this goal has been achieved by hydrogen bonding or molecular encapsulation, a Lewis acid-binding strategy for redox amplification of quinones is unexplored. Herein, the redox chemistry of silicon tris(perchloro)dioxolene 1 was studied, which is the formal adduct of ortho-perchloroquinone QCl with the Lewis superacid bis(perchlorocatecholato)silane 2. By isolating the anionic monoradical 1.- , the redox-series of a century-old class of compounds was completed. Cyclic voltammetry measurements revealed that the redox potential in 1 was shifted by more than 1 V into the anodic direction compared to QCl , reaching that of "magic blue" or NO+ . It allowed oxidation of challenging substrates such as aromatic hydrocarbons and could be applied as an efficient redox catalyst. Remarkably, this powerful reagent formed in situ by combining the two commercially available precursors SiI4 and QCl .
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Affiliation(s)
- Rezisha Maskey
- Institute of Inorganic Chemistry, Ruprecht Karl University Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Christoph Bendel
- Institute of Inorganic Chemistry, Ruprecht Karl University Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Jonas Malzacher
- Institute of Inorganic Chemistry, Ruprecht Karl University Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Lutz Greb
- Institute of Inorganic Chemistry, Ruprecht Karl University Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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10
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Holtrop F, Jupp AR, Kooij BJ, van Leest NP, de Bruin B, Slootweg JC. Single-Electron Transfer in Frustrated Lewis Pair Chemistry. Angew Chem Int Ed Engl 2020; 59:22210-22216. [PMID: 32840947 PMCID: PMC7756365 DOI: 10.1002/anie.202009717] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Indexed: 02/05/2023]
Abstract
Frustrated Lewis pairs (FLPs) are well known for their ability to activate small molecules. Recent reports of radical formation within such systems indicate single-electron transfer (SET) could play an important role in their chemistry. Herein, we investigate radical formation upon reacting FLP systems with dihydrogen, triphenyltin hydride, or tetrachloro-1,4-benzoquinone (TCQ) both experimentally and computationally to determine the nature of the single-electron transfer (SET) events; that is, being direct SET to B(C6 F5 )3 or not. The reactions of H2 and Ph3 SnH with archetypal P/B FLP systems do not proceed via a radical mechanism. In contrast, reaction with TCQ proceeds via SET, which is only feasible by Lewis acid coordination to the substrate. Furthermore, SET from the Lewis base to the Lewis acid-substrate adduct may be prevalent in other reported examples of radical FLP chemistry, which provides important design principles for radical main-group chemistry.
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Affiliation(s)
- Flip Holtrop
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Andrew R. Jupp
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Bastiaan J. Kooij
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Nicolaas P. van Leest
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - Bas de Bruin
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
| | - J. Chris Slootweg
- Van't Hoff Institute for Molecular SciencesUniversity of AmsterdamPO Box 941571090 GDAmsterdamThe Netherlands
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11
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Zhong C, Zhao H, Han Q, Cao H, Duan F, Shen J, Xie Y, Guo W, Sun S. Coupling-oxidation process promoted ring-opening degradation of 2-mecapto-5-methyl-1,3,4-thiadizaole in wastewater. WATER RESEARCH 2020; 186:116362. [PMID: 32916619 DOI: 10.1016/j.watres.2020.116362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/28/2020] [Accepted: 08/29/2020] [Indexed: 06/11/2023]
Abstract
As an important raw material and intermediate of widely used antibiotics cefazolin and cefazedone, 2-mecapto-5-methyl-1,3,4-thiadizaole (MMTD) in antibiotic wastewater is hardly decyclized during wastewater treatment, posing great risk to the environment. This work proposed a green "coupling-oxidation" process to enhance ring-opening of MMTD during antibiotic wastewater treatment. In particular, the significant role of humic substances (HS) as pre-coupling reagent was emphasized. Real HS and different model HS, especially quinones, not only efficiently pre-coupled MMTD (>95%) but also promoted the MMTD removal by MnO2 (from 72.4% to 92.4%). Mass spectrometric analysis indicated that MMTD pre-coupled to HS would be oxidized with ring opening to environmental-friendly sulfonated HS, while direct oxidation of MMTD produced MMTD dimers or sulfonated MMTD that would not undergo ring opening. Theoretical calculations indicated that pre-coupling to HS enabled the ring-opening oxidation by increasing the nucleophilicity and decreasing ring-opening barrier of thiadiazole. Based on the density function theory (DFT), the global nucleophilicity index (Nu) followed the trend of HS-MMTD > MMTD dimer > sulfonated MMTD, while the ring-opening barrier followed the trend of HS-MMTD (274 kJ/mol) < first ring of MMTD dimers (286 kJ/mol) < MMTD (338 kJ/mol). Theoretical calculations further confirmed that the cross-coupled HS-MMTD intermediate was more likely to be decyclized than intermediates from direct oxidation. Moreover, nitrogen, acetaldehyde group, sulfate and CO2 were the products of thiadiazole ring degradation. Pre-coupling of MMTD with HS provides a new idea and strategy in developing a green and sustainable scheme for wastewater treatment.
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Affiliation(s)
- Chen Zhong
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - He Zhao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Beijing Engineering Research Center of Process Pollution Control, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China.
| | - Qingzhen Han
- Beijing Engineering Research Center of Process Pollution Control, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
| | - Hongbin Cao
- Beijing Engineering Research Center of Process Pollution Control, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
| | - Feng Duan
- Beijing Engineering Research Center of Process Pollution Control, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
| | - Junyi Shen
- Beijing Engineering Research Center of Process Pollution Control, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China; Suzhou University of Science and Technology, Suzhou 215009, Jiangsu, China
| | - Yongbing Xie
- Beijing Engineering Research Center of Process Pollution Control, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
| | - Wanqian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shanshan Sun
- Beijing Engineering Research Center of Process Pollution Control, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
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12
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Choi H, Baek K, Toenjes ST, Gustafson JL, Smith DK. Redox-Responsive H-Bonding: Amplifying the Effect of Electron Transfer Using Proton-Coupled Electron Transfer. J Am Chem Soc 2020; 142:17271-17276. [PMID: 32981317 DOI: 10.1021/jacs.0c07841] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A new strategy to create highly redox-responsive H-bond dimers based on proton-coupled electron transfer is proposed that capitalizes on the importance of secondary H-bonds in determining overall binding strength in H-bond dimers. Electron transfer induced proton transfer across a H-bond can be used to significantly strengthen the overall binding by both creating strong ionic H-bonds and changing the secondary H-bonds from unfavorable to favorable. The viability and potency of this approach are demonstrated with an electroactive DAD (A = H-acceptor, D = H-donor) array, H(MQ+)H, paired with an electroinactive ADA array, O(NH)O. NMR titration of H(MQ+)H with O(NH)O in 0.1 M NBu4PF6/CD2Cl2 gives a Kassoc of 500 M-1, typical of DAD-ADA dimers. However, upon two-electron reduction in 0.1 M NBu4PF6/CH2Cl2, cyclic voltammetry studies indicate a 1.8 × 105 increase in binding strength, corresponding to a very large Kassoc of 9 × 107 M-1. The latter value is typical of DDD-AAA H-bond dimers, consistent with proton transfer across the central H-bond upon reduction.
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Affiliation(s)
- Hyejeong Choi
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, United States
| | - Kiyeol Baek
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, United States
| | - Sean T Toenjes
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, United States
| | - Jeffrey L Gustafson
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, United States
| | - Diane K Smith
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, United States
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13
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Ng KKL, Devlia R, Foss NL, Alesbrook LS, Hiscock JR, Murray AT. Ionicity-dependent proton-coupled electron transfer of supramolecular self-assembled electroactive heterocycles. Chem Commun (Camb) 2020; 56:11815-11818. [PMID: 33021265 DOI: 10.1039/d0cc05017b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we investigate the electrochemical properties of a class of Supramolecular Self-associated Amphiphilic salts (SSAs). We show that varying ionic strength of an SSA solution can cause a switching of the thermodynamics and kinetics of electron transfer. The effect of self-assembly on proton-coupled electron transfer has implications for the understanding of electron transfer kinetics in aqueous organic redox flow batteries, especially at high concentration where organic-organic intermolecular interactions become dominant even for highly soluble organic species.
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Affiliation(s)
- Kendrick K L Ng
- University of Kent, Park Wood Road, Canterbury, Kent, CT2 7NH, UK.
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14
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Verma A, Shivalkar S, Sk MP, Samanta SK, Sahoo AK. Nanocomposite of Ag nanoparticles and catalytic fluorescent carbon dots for synergistic bactericidal activity through enhanced reactive oxygen species generation. NANOTECHNOLOGY 2020; 31:405704. [PMID: 32498056 DOI: 10.1088/1361-6528/ab996f] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Microwave mediated synthesis of catalytic fluorescent carbon dots (Cdots) has been reported using biodegradable starch as precursor. The as-synthesized Cdots were then characterized using various techniques such as fluorescence spectroscopy, fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS) analysis. Interestingly, Cdots showed high catalytic activity in the photo-reduction of Ag+ to silver nanoparticles (Ag NPs). During the photo-reduction process, no additional surface passivating agents was needed to stabilize the Ag NPs. Further, TEM results indicated the formation of Cdot-Ag NP nanocomposite i.e. Ag NPs surrounded with Cdots, and the emission intensity of Cdots was significantly decreased whereas the lifetime of Cdots remained almost unaltered in the presence of Ag NPs following static quenching. Finally, combination therapy of Cdots and Ag NPs using Cdot-Ag NP nanocomposite was performed which indicated synergistic bactericidal activity against antibiotic resistant recombinant E. coli bacteria. The treatment elevated the reactive oxygen species (ROS) level as compared to its individual components. Additionally, the flow cytometer study demonstrated that combination therapy causing bacterial cell wall perforation that was possibly leading to synergistic bactericidal activity against both Gram positive and Gram negative bacteria. The presence of Cdots on the surface of the Ag NPs due to their ground state complexation, possibly facilitated electrons towards Ag NPs which enhanced the ROS production in comparison to only Ag NPs.
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Affiliation(s)
- Arushi Verma
- Department of Applied Sciences, Indian Institute of Information Technology Allahabad, Allahabad 211012, Uttar Pradesh, India
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15
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Holtrop F, Jupp AR, Kooij BJ, Leest NP, Bruin B, Slootweg JC. Single‐Electron Transfer in Frustrated Lewis Pair Chemistry. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009717] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Flip Holtrop
- Van't Hoff Institute for Molecular Sciences University of Amsterdam PO Box 94157 1090 GD Amsterdam The Netherlands
| | - Andrew R. Jupp
- Van't Hoff Institute for Molecular Sciences University of Amsterdam PO Box 94157 1090 GD Amsterdam The Netherlands
| | - Bastiaan J. Kooij
- Van't Hoff Institute for Molecular Sciences University of Amsterdam PO Box 94157 1090 GD Amsterdam The Netherlands
| | - Nicolaas P. Leest
- Van't Hoff Institute for Molecular Sciences University of Amsterdam PO Box 94157 1090 GD Amsterdam The Netherlands
| | - Bas Bruin
- Van't Hoff Institute for Molecular Sciences University of Amsterdam PO Box 94157 1090 GD Amsterdam The Netherlands
| | - J. Chris Slootweg
- Van't Hoff Institute for Molecular Sciences University of Amsterdam PO Box 94157 1090 GD Amsterdam The Netherlands
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16
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Yin Z, Xiao Y, Li H, Chen G, Feng N, Wu J, Li H, Xu H, Cao S. Metal Nanoparticles Confined within an Inorganic-Organic Framework Enable Superior Substrate-Selective Catalysis. ACS APPLIED MATERIALS & INTERFACES 2020; 12:42739-42748. [PMID: 32864954 DOI: 10.1021/acsami.0c10814] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The search for catalysts with a perfect substrate selectivity toward the hydrogenation of nitroarenes is a goal of high importance, which still remains a significant challenge. Here, we designed a new type of catalyst with superior substrate selectivity by combining a space-confined effect and a hydrogen-bonding network, in which metal nanoparticles (MNPs) were confined in hierarchical hollow silica (HHS) with a poly(N-isopropylacrylamide) (PNIPA) coating. Given the strong induced properties of hydrogen-bond donors and acceptors in the HHS support and PNIPA coating, the as-synthesized catalyst would achieve perfect substrate selectivity for the hydrogenation of various nitroarenes and their mixture by thoroughly impeding the reduction of nitroarenes with any hydroxyl or carboxyl groups, which is typically very difficult to be realized over almost all of the reported supported-metal catalysts. Notably, the hydrogenation of nitroarenes can produce almost quantitative yields of anilines over the as-synthesized catalyst. Furthermore, density functional theory and experimental evidence are also provided for the hierarchical structure of HHS and PNIPA coating associated with substrates to demonstrate how a substrate could have access or be blocked into the confined active centers (MNPs). Therefore, this work would open a new window to design efficient catalysts for a wide variety of substrate-selective catalyses.
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Affiliation(s)
- Zhengliang Yin
- School of Materials Science and Engineering, Institute for Energy Research, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Yingguan Xiao
- School of Materials Science and Engineering, Institute for Energy Research, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Hongping Li
- School of Materials Science and Engineering, Institute for Energy Research, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Gang Chen
- School of Materials Science and Engineering, Institute for Energy Research, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Ningdong Feng
- Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Jingjie Wu
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Huaming Li
- School of Materials Science and Engineering, Institute for Energy Research, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Hui Xu
- School of Materials Science and Engineering, Institute for Energy Research, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Shunsheng Cao
- School of Materials Science and Engineering, Institute for Energy Research, Jiangsu University, Zhenjiang 212013, P. R. China
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17
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Li X, Xu J, Li SJ, Qu LB, Li Z, Chi YR, Wei D, Lan Y. Prediction of NHC-catalyzed chemoselective functionalizations of carbonyl compounds: a general mechanistic map. Chem Sci 2020; 11:7214-7225. [PMID: 34123007 PMCID: PMC8159411 DOI: 10.1039/d0sc01793k] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Generally, N-heterocyclic carbene (NHC) complexed with carbonyl compounds would transform into several important active intermediates, i.e., enolates, Breslow intermediates, or acylazolium intermediates, which act as either a nucleophile (Nu) or an electrophile (E) to react with the other E/Nu partner. Hence, the key to predicting the origin of chemoselectivity is to compute the activity (i.e., electrophilic index ω for E and nucleophilic index N for Nu) and stability of the intermediates and products, which are suggested in a general mechanistic map of these reactions. To support this point, we selected and studied different cases of the NHC-catalyzed reactions of carbonyl compounds in the presence of a base and/or an oxidant, in which multiple possible pathways involving acylazolium, enolate, Breslow, and α,β-unsaturated acylazolium intermediates were proposed and a novel index ω + N of the E and Nu partners was employed to exactly predict the energy barrier of the chemoselective step in theory. This work provides a guide for determining the general principle behind organocatalytic reactions with various chemoselectivities, and suggests a general application of the reaction index in predicting the chemoselectivity of the nucleophilic and electrophilic reactions. A novel index ω + N can be used to predict the chemoselectivity according to the general NHC-catalyzed reaction mechanism.![]()
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Affiliation(s)
- Xue Li
- College of Chemistry, Institute of Green Catalysis, Zhengzhou University 100 Science Avenue Zhengzhou Henan 450001 China
| | - Jun Xu
- College of Pharmacy, Guizhou University of Traditional Chinese Medicine Guiyang China
| | - Shi-Jun Li
- College of Chemistry, Institute of Green Catalysis, Zhengzhou University 100 Science Avenue Zhengzhou Henan 450001 China
| | - Ling-Bo Qu
- College of Chemistry, Institute of Green Catalysis, Zhengzhou University 100 Science Avenue Zhengzhou Henan 450001 China
| | - Zhongjun Li
- College of Chemistry, Institute of Green Catalysis, Zhengzhou University 100 Science Avenue Zhengzhou Henan 450001 China
| | - Yonggui Robin Chi
- Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore
| | - Donghui Wei
- College of Chemistry, Institute of Green Catalysis, Zhengzhou University 100 Science Avenue Zhengzhou Henan 450001 China
| | - Yu Lan
- College of Chemistry, Institute of Green Catalysis, Zhengzhou University 100 Science Avenue Zhengzhou Henan 450001 China .,College of Chemistry and Chemical Engineering, Chongqing University Chongqing 400044 China
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18
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Abstract
The genes for Monascus naphthoquinone (monasone) biosynthesis are embedded in and form a composite supercluster with the Monascus azaphilone pigment biosynthetic gene cluster. Early biosynthetic intermediates are shared by the two pathways. Some enzymes encoded by the supercluster play double duty in contributing to both pathways, while others are specific for one or the other pathway. The monasone subcluster is independently regulated and inducible by elicitation with competing microorganisms. This study illustrates genomic and biosynthetic parsimony in fungi and proposes a potential path for the evolution of the mosaic-like azaphilone-naphthoquinone supercluster. The monasone subcluster also encodes a two-tiered self-resistance mechanism that models resistance determinants that may transfer to target microorganisms or emerge in cancer cells in case of naphthoquinone-type cytotoxic agents. Despite the important biological activities of natural product naphthoquinones, the biosynthetic pathways of and resistance mechanisms against such compounds remain poorly understood in fungi. Here, we report that the genes responsible for the biosynthesis of Monascus naphthoquinones (monasones) reside within the gene cluster for Monascus azaphilone pigments (MonAzPs). We elucidate the biosynthetic pathway of monasones by a combination of comparative genome analysis, gene knockouts, heterologous coexpression, and in vivo and in vitro enzymatic reactions to show that this pathway branches from the first polyketide intermediate of MonAzPs. Furthermore, we propose that the monasone subset of biosynthetic genes also encodes a two-tiered resistance strategy in which an inducible monasone-specific exporter expels monasones from the mycelia, while residual intracellular monasones may be rendered nontoxic through a multistep reduction cascade.
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19
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Spicer RL, Stergiou AD, Young TA, Duarte F, Symes MD, Lusby PJ. Host–Guest-Induced Electron Transfer Triggers Radical-Cation Catalysis. J Am Chem Soc 2020; 142:2134-2139. [DOI: 10.1021/jacs.9b11273] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Rebecca L. Spicer
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Athanasios D. Stergiou
- WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow G12 8QQ, U.K
| | - Tom A. Young
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Fernanda Duarte
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Mark D. Symes
- WestCHEM, School of Chemistry, University of Glasgow, University Avenue, Glasgow G12 8QQ, U.K
| | - Paul J. Lusby
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
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20
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Wild U, Hübner O, Himmel H. Redox-Active Guanidines in Proton-Coupled Electron-Transfer Reactions: Real Alternatives to Benzoquinones? Chemistry 2019; 25:15988-15992. [PMID: 31535741 PMCID: PMC7065378 DOI: 10.1002/chem.201903438] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Indexed: 01/24/2023]
Abstract
Guanidino-functionalized aromatics (GFAs) are readily available, stable organic redox-active compounds. In this work we apply one particular GFA compound, 1,2,4,5-tetrakis(tetramethylguanidino)benzene, in its oxidized form in a variety of oxidation/oxidative coupling reactions to demonstrate the scope of its proton-coupled electron transfer (PCET) reactivity. Addition of an excess of acid boosts its oxidation power, enabling the oxidative coupling of substrates with redox potentials of at least +0.77 V vs. Fc+ /Fc. The green recyclability by catalytic re-oxidation with dioxygen is also shown. Finally, a direct comparison indicates that GFAs are real alternatives to toxic halo- or cyano-substituted benzoquinones.
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Affiliation(s)
- Ute Wild
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Olaf Hübner
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Hans‐Jörg Himmel
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
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21
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Palladium-catalyzed Suzuki-Miyaura coupling of thioureas or thioamides. Nat Commun 2019; 10:5709. [PMID: 31836718 PMCID: PMC6911099 DOI: 10.1038/s41467-019-13701-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 11/19/2019] [Indexed: 11/08/2022] Open
Abstract
Cross-coupling reactions involving metal carbene intermediates play an increasingly important role in C-C bond formation. Expanding the carbene precursors to a broader range of starting materials and more diverse products is an ongoing challenge in synthetic organic chemistry. Herein, we report a Suzuki-Miyaura coupling reaction of in situ-generated Pd-carbene complexes via desulfurization of thioureas or thioamides. This strategy enables the preparation of a broad array of substituted amidinium salts and unsymmetrical diaryl ketones. The reaction is readily scalable, compatible with bromo groups on aromatic rings, tolerant to moisture and air and has a broad substrate scope. Furthermore, a single crystal structure of Pd-diaminocarbene complex is obtained and proven to be the key intermediate in both catalytic and stoichiometric reactions. Preliminary mechanistic studies demonstrate the dual role of the silver salt as a desulfurating reagent assisting the elimination of sulfur and as oxidant facilitating the PdII/Pd0/PdII catalytic cycle.
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22
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Biswas S, Bhattacharya I, Chakraborty T. Identification of an Emitting Metastable State of p-Fluorophenol-Ammonia 1:2 Complex by Laser-Induced Fluorescence Spectroscopy. J Phys Chem A 2019; 123:10563-10570. [PMID: 31714082 DOI: 10.1021/acs.jpca.9b07958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have demonstrated here, for the first time to our knowledge, the formation of an emitting metastable species upon lowest electronic excitation (S1) of a hydrogen-bonded 1:2 complex of para-fluorophenol (pFP) with ammonia (NH3), which is known to be one of the smallest reactive complexes to undergo excited state H-atom transfer (HAT) reaction to produce •NH4(NH3) radical fragment. The emission spectrum of the species is characterized to be red-shifted, broad, and structureless. From the viewpoint of energy balance, an excited state proton transfer (ESPT) is unfavorable, but according to predicted electronic structure parameters, the metastable state species could be stabilized by charge transfer (CT) interaction at the hydrogen-bonded geometry of the complex. We propose that this species could act as an intermediate to the HAT process in the excited state. The observation of such a state could be valuable to understand the complex dynamics of similar events in biologically relevant systems.
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Affiliation(s)
- Souvick Biswas
- School of Chemical Sciences , Indian Association for the Cultivation of Science , 2A Raja S C Mullick Road, Jadavpur , Kolkata 700032 , India
| | - Indrani Bhattacharya
- School of Chemical Sciences , Indian Association for the Cultivation of Science , 2A Raja S C Mullick Road, Jadavpur , Kolkata 700032 , India
| | - Tapas Chakraborty
- School of Chemical Sciences , Indian Association for the Cultivation of Science , 2A Raja S C Mullick Road, Jadavpur , Kolkata 700032 , India
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23
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Ibacache JA, Valderrama JA, Faúndes J, Danimann A, Recio FJ, Zúñiga CA. Green Synthesis and Electrochemical Properties of Mono- and Dimers Derived from Phenylaminoisoquinolinequinones. Molecules 2019; 24:E4378. [PMID: 31801190 PMCID: PMC6930604 DOI: 10.3390/molecules24234378] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 01/08/2023] Open
Abstract
In the search for new quinoid compounds endowed with potential anticancer activity, the synthesis of novel heterodimers containing the cytotoxic 7-phenylaminoisoquinolinequinone and 2-phenylaminonaphthoquinone pharmacophores, connected through methylene and ethylene spacers, is reported. The heterodimers were prepared from their respective isoquinoline and naphthoquinones and 4,4'-diaminodiphenyl alkenes. The access to the target heterodimers and their corresponding monomers was performed both through oxidative amination reactions assisted by ultrasound and CeCl3·7H2O catalysis "in water". This eco-friendly procedure was successfully extended to the one-pot synthesis of homodimers derived from the 7-phenylaminoisoquinolinequinone pharmacophore. The electrochemical properties of the monomers and dimers were determined by cyclic and square wave voltammetry. The number of electrons transferred during the oxidation process, associated to the redox potential EI1/2, was determined by controlled potential coulometry.
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Affiliation(s)
- Juana Andrea Ibacache
- Facultad de Química y Biología, Universidad de Santiago de Chile, Alameda 3363, casilla 40, Santiago 9170022, Chile; (J.F.); (A.D.)
| | - Jaime A. Valderrama
- Facultad de Ciencias de la Salud, Universidad Arturo Prat, casilla 121, Iquique 1100000, Chile
| | - Judith Faúndes
- Facultad de Química y Biología, Universidad de Santiago de Chile, Alameda 3363, casilla 40, Santiago 9170022, Chile; (J.F.); (A.D.)
| | - Alex Danimann
- Facultad de Química y Biología, Universidad de Santiago de Chile, Alameda 3363, casilla 40, Santiago 9170022, Chile; (J.F.); (A.D.)
| | - Francisco J. Recio
- Facultad de Química y Farmacia, Universidad Católica de Chile, casilla 306, Santiago 7820436, Chile; (F.J.R.); (C.A.Z.)
| | - César A. Zúñiga
- Facultad de Química y Farmacia, Universidad Católica de Chile, casilla 306, Santiago 7820436, Chile; (F.J.R.); (C.A.Z.)
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24
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Liu C, Niazi MR, Perepichka DF. Strong Enhancement of π‐Electron Donor/Acceptor Ability by Complementary DD/AA Hydrogen Bonding. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910288] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Cheng‐Hao Liu
- Department of ChemistryMcGill University 801 Sherbrooke Street W Quebec H3A 0B1 Canada
| | - Muhammad Rizwan Niazi
- Department of ChemistryMcGill University 801 Sherbrooke Street W Quebec H3A 0B1 Canada
| | - Dmitrii F. Perepichka
- Department of ChemistryMcGill University 801 Sherbrooke Street W Quebec H3A 0B1 Canada
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25
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Liu CH, Niazi MR, Perepichka DF. Strong Enhancement of π-Electron Donor/Acceptor Ability by Complementary DD/AA Hydrogen Bonding. Angew Chem Int Ed Engl 2019; 58:17312-17321. [PMID: 31560447 DOI: 10.1002/anie.201910288] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Indexed: 11/11/2022]
Abstract
π-Conjugated organic materials possess a wide range of tunable optoelectronic properties which are dictated by their molecular structure and supramolecular arrangement. While many efforts have been put into tuning the molecular structure to achieve the desired properties, rational supramolecular control remains a challenge. Here, we report a novel series of supramolecular materials formed by the co-assembly of weak π-electron donor (indolo[2,3-a]carbazole) and acceptor (aromatic o-quinones) molecules via complementary hydrogen bonding. The resulting polarization creates a drastic perturbation of the molecular energy levels, causing strong charge transfer in the weak donor-acceptor pairs. This leads to a significant lowering (up to 1.5 eV) of the band gaps, intense absorption in the near-IR region, very short π-stacking distances (≥3.15 Å), and strong ESR signals in the co-crystals. By varying the strength of the acceptor, the characteristics of the complexes can be tuned between intrinsic, gate-, or light-induced semiconductivity with a p-type or ambipolar transport mechanism.
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Affiliation(s)
- Cheng-Hao Liu
- Department of Chemistry, McGill University, 801 Sherbrooke Street W, Quebec, H3A 0B1, Canada
| | - Muhammad Rizwan Niazi
- Department of Chemistry, McGill University, 801 Sherbrooke Street W, Quebec, H3A 0B1, Canada
| | - Dmitrii F Perepichka
- Department of Chemistry, McGill University, 801 Sherbrooke Street W, Quebec, H3A 0B1, Canada
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26
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Complexes of damirone A/C, batzelline A/D, makaluvamine O and makaluvone with guanidinium and magnesium cations: a theoretical study. Struct Chem 2019. [DOI: 10.1007/s11224-019-01325-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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27
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Milić JV, Schneeberger T, Zalibera M, Diederich F, Boudon C, Ruhlmann L. Spectro-electrochemical toolbox for monitoring and controlling quinone-mediated redox-driven molecular gripping. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.04.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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28
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Koike T, Kosai T, Iwamoto T. 1,4‐Dehydrogenation with a Two‐Coordinate Cyclic (Alkyl)(amino)silylene. Chemistry 2019; 25:9295-9302. [DOI: 10.1002/chem.201901407] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/26/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Taichi Koike
- Department of ChemistryGraduate School of ScienceTohoku University Aoba-ku Sendai 980-8578 Japan
| | - Tomoyuki Kosai
- Department of ChemistryGraduate School of ScienceTohoku University Aoba-ku Sendai 980-8578 Japan
| | - Takeaki Iwamoto
- Department of ChemistryGraduate School of ScienceTohoku University Aoba-ku Sendai 980-8578 Japan
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29
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Sandoval BA, Kurtoic SI, Chung MM, Biegasiewicz KF, Hyster TK. Photoenzymatic Catalysis Enables Radical-Mediated Ketone Reduction in Ene-Reductases. Angew Chem Int Ed Engl 2019; 58:8714-8718. [PMID: 30951226 PMCID: PMC6570536 DOI: 10.1002/anie.201902005] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/22/2019] [Indexed: 11/12/2022]
Abstract
Flavin-dependent ene-reductases (EREDs) are known to stereoselectively reduce activated alkenes, but are inactive toward carbonyls. Demonstrated here is that in the presence of photoredox catalysts, these enzymes will reduce aromatic ketones. Mechanistic experiments suggest this reaction proceeds through ketyl radical formation, a reaction pathway that is distinct from the native hydride-transfer mechanism. Furthermore, this reactivity is accessible without modification of either the enzyme or cofactors, allowing both native and non-natural mechanisms to occur simultaneously. Based on control experiments, we hypothesize that binding to the enzyme active site attenuates the reduction potential of the substrate, enabling single-electron reduction. This reactivity highlights opportunities to access new catalytic manifolds by merging photoredox catalysis with biocatalysis.
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Affiliation(s)
- Braddock A Sandoval
- Department of Chemistry, Princeton University, Frick Chemical Laboratory, Princeton, NJ, 08544, USA
| | - Sarah I Kurtoic
- Department of Chemistry, Princeton University, Frick Chemical Laboratory, Princeton, NJ, 08544, USA
| | - Megan M Chung
- Department of Chemistry, Princeton University, Frick Chemical Laboratory, Princeton, NJ, 08544, USA
| | - Kyle F Biegasiewicz
- Department of Chemistry, Princeton University, Frick Chemical Laboratory, Princeton, NJ, 08544, USA
| | - Todd K Hyster
- Department of Chemistry, Princeton University, Frick Chemical Laboratory, Princeton, NJ, 08544, USA
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30
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Milić JV, Diederich F. The Quest for Molecular Grippers: Photo‐Electric Control of Molecular Gripping Machinery. Chemistry 2019; 25:8440-8452. [DOI: 10.1002/chem.201900852] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 03/25/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Jovana V. Milić
- Laboratory of Photonics and InterfacesÉcole Polytechnique Fédéralé de Lausanne 1015 Lausanne Switzerland
| | - François Diederich
- Department of Chemistry and Applied BiosciencesETH Zurich Vladimir-Prelog-Weg 3 8010 Zurich Switzerland
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31
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Sandoval BA, Kurtoic SI, Chung MM, Biegasiewicz KF, Hyster TK. Photoenzymatic Catalysis Enables Radical‐Mediated Ketone Reduction in Ene‐Reductases. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902005] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Braddock A. Sandoval
- Department of ChemistryPrinceton UniversityFrick Chemical Laboratory Princeton NJ 08544 USA
| | - Sarah I. Kurtoic
- Department of ChemistryPrinceton UniversityFrick Chemical Laboratory Princeton NJ 08544 USA
| | - Megan M. Chung
- Department of ChemistryPrinceton UniversityFrick Chemical Laboratory Princeton NJ 08544 USA
| | - Kyle F. Biegasiewicz
- Department of ChemistryPrinceton UniversityFrick Chemical Laboratory Princeton NJ 08544 USA
| | - Todd K. Hyster
- Department of ChemistryPrinceton UniversityFrick Chemical Laboratory Princeton NJ 08544 USA
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32
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Liu JJ. Photochromism and decolorization controlled by auxiliary ligands of complexes derived from 1-methyl-4,4′-bipyridinium cation. Appl Organomet Chem 2019. [DOI: 10.1002/aoc.4578] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Jin-jian Liu
- Key Laboratory of Magnetic Molecules, Magnetic Information Materials Ministry of Education, School of Chemical and Material Science; Shanxi Normal University; Linfen 041004 China
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33
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Wild U, Hübner O, Greb L, Enders M, Kaifer E, Himmel HJ. Twofold Oxidized and Twofold Protonated Redox-Active Guanidine: An Ultimate Intermediate in Proton-Coupled Electron-Transfer Reactions. European J Org Chem 2018. [DOI: 10.1002/ejoc.201801378] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ute Wild
- Anorganisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Olaf Hübner
- Anorganisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Lutz Greb
- Anorganisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Markus Enders
- Anorganisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Hans-Jörg Himmel
- Anorganisch-Chemisches Institut; Ruprecht-Karls-Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Germany
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Ruccolo S, Qin Y, Schnedermann C, Nocera DG. General Strategy for Improving the Quantum Efficiency of Photoredox Hydroamidation Catalysis. J Am Chem Soc 2018; 140:14926-14937. [DOI: 10.1021/jacs.8b09109] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Serge Ruccolo
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138−2902, United States
| | - Yangzhong Qin
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138−2902, United States
| | - Christoph Schnedermann
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138−2902, United States
| | - Daniel G. Nocera
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138−2902, United States
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Li X, Wang Y, Wang Y, Tang M, Qu LB, Li Z, Wei D. Insights into the N-Heterocyclic Carbene (NHC)-Catalyzed Oxidative γ-C(sp 3)-H Deprotonation of Alkylenals and Cascade [4 + 2] Cycloaddition with Alkenylisoxazoles. J Org Chem 2018; 83:8543-8555. [PMID: 29927597 DOI: 10.1021/acs.joc.8b01112] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The N-heterocyclic carbene (NHC)-catalyzed oxidative C-H deprotonations have attracted increasing attention; however, the general mechanism regarding this kind of oxidative organocatalysis remains unclear. In this paper, the competing mechanisms and origin of the stereoselectivity of the NHC-catalyzed oxidative γ-C(sp3)-H deprotonation of alkylenals and cascade [4 + 2] cycloaddition with alkenylisoxazoles were systematically investigated for the first time using density functional theory (DFT). The computed results indicate that the oxidation of the Breslow intermediate by 3,3',5,5'-tetra- tert-butyl diphenoquinone (DQ) via a hydride transfer to oxygen (HTO) pathway is the most favorable among the four competing pathways. In addition, the analyses demonstrate that oxidant DQ plays a double role, i.e., strengthening the acidity of the hydrogen of the γ-carbon of alkylenal and forming π···π interactions with conjugated C═C bonds to promote the γ-C(sp3)-H deprotonation. The NHC catalyst acts as a Lewis base, and the hydrogen-bond network between the NHC and the substrate formed in the key Michael addition step is responsible for the origin of the stereoselectivity. Further DFT calculations reveal that the nonpolar solvent can stabilize the nonpolar R isomer but destabilize the polar S isomer for the stereoselectivity-determining transition states, thus improving the stereoselectivity.
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36
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Gentry EC, Rono LJ, Hale ME, Matsuura R, Knowles RR. Enantioselective Synthesis of Pyrroloindolines via Noncovalent Stabilization of Indole Radical Cations and Applications to the Synthesis of Alkaloid Natural Products. J Am Chem Soc 2018; 140:3394-3402. [PMID: 29432006 PMCID: PMC5896747 DOI: 10.1021/jacs.7b13616] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
While interest in the synthetic chemistry of radical cations continues to grow, controlling enantioselectivity in the reactions of these intermediates remains a challenge. Based on recent insights into the oxidation of tryptophan in enzymatic systems, we report a photocatalytic method for the generation of indole radical cations as hydrogen-bonded adducts with chiral phosphate anions. These noncovalent open-shell complexes can be intercepted by the stable nitroxyl radical TEMPO· to form alkoxyamine-substituted pyrroloindolines with high levels of enantioselectivity. Further elaboration of these optically enriched adducts can be achieved via a catalytic single-electron oxidation/mesolytic cleavage sequence to furnish transient carbocation intermediates that may be intercepted by a wide range of nucleophiles. Taken together, this two-step sequence provides a simple catalytic method to access a wide range of substituted pyrroloindolines in enantioenriched form via a standard experimental protocol from a common synthetic intermediate. The design, development, mechanistic study, and scope of this process are presented, as are applications of this method to the synthesis of several dimeric pyrroloindoline natural products.
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Affiliation(s)
- Emily C. Gentry
- Department of Chemistry, Princeton University, Princeton NJ 08544, USA
| | - Lydia J. Rono
- Department of Chemistry, Princeton University, Princeton NJ 08544, USA
| | - Martina E. Hale
- Department of Chemistry, Princeton University, Princeton NJ 08544, USA
| | - Rei Matsuura
- Department of Chemistry, Princeton University, Princeton NJ 08544, USA
| | - Robert R. Knowles
- Department of Chemistry, Princeton University, Princeton NJ 08544, USA
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37
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Huang X, Wang J, Li T, Wang J, Xu M, Yu W, El Abed A, Zhang X. Review on optofluidic microreactors for artificial photosynthesis. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:30-41. [PMID: 29379698 PMCID: PMC5769083 DOI: 10.3762/bjnano.9.5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 12/06/2017] [Indexed: 05/23/2023]
Abstract
Artificial photosynthesis (APS) mimics natural photosynthesis (NPS) to store solar energy in chemical compounds for applications such as water splitting, CO2 fixation and coenzyme regeneration. NPS is naturally an optofluidic system since the cells (typical size 10 to 100 µm) of green plants, algae, and cyanobacteria enable light capture, biochemical and enzymatic reactions and the related material transport in a microscale, aqueous environment. The long history of evolution has equipped NPS with the remarkable merits of a large surface-area-to-volume ratio, fast small molecule diffusion and precise control of mass transfer. APS is expected to share many of the same advantages of NPS and could even provide more functionality if optofluidic technology is introduced. Recently, many studies have reported on optofluidic APS systems, but there is still a lack of an in-depth review. This article will start with a brief introduction of the physical mechanisms and will then review recent progresses in water splitting, CO2 fixation and coenzyme regeneration in optofluidic APS systems, followed by discussions on pending problems for real applications.
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Affiliation(s)
- Xiaowen Huang
- Energy Research Institute, Shandong Academy of Sciences, Jinan, Shandong 250014, China
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China
| | - Jianchun Wang
- Energy Research Institute, Shandong Academy of Sciences, Jinan, Shandong 250014, China
| | - Tenghao Li
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China
| | - Jianmei Wang
- Energy Research Institute, Shandong Academy of Sciences, Jinan, Shandong 250014, China
| | - Min Xu
- Energy Research Institute, Shandong Academy of Sciences, Jinan, Shandong 250014, China
| | - Weixing Yu
- Key Laboratory of Spectral Imaging Technology, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an, Shaanxi 710119, China
| | - Abdel El Abed
- Laboratoire de Photonique Quantique et Moléculaire, UMR 8537, Ecole Normale Supérieure de Cachan, CentraleSupélec, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan, France
| | - Xuming Zhang
- Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China
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38
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Milić J, Zalibera M, Talaat D, Nomrowski J, Trapp N, Ruhlmann L, Boudon C, Wenger OS, Savitsky A, Lubitz W, Diederich F. Photoredox-Switchable Resorcin[4]arene Cavitands: Radical Control of Molecular Gripping Machinery via Hydrogen Bonding. Chemistry 2017; 24:1431-1440. [DOI: 10.1002/chem.201704788] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Indexed: 01/10/2023]
Affiliation(s)
- Jovana Milić
- Laboratory of Organic Chemistry; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Michal Zalibera
- Institute of Physical Chemistry and Chemical Physics; Slovak University of Technology; Radlinského 9 81237 Bratislava Slovakia
- Max Planck Institute for Chemical Energy Conversion; Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
| | - Darius Talaat
- Laboratory of Organic Chemistry; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Julia Nomrowski
- Department of Chemistry; University of Basel; St. Johanns-Ring 19 4056 Basel Switzerland
| | - Nils Trapp
- Laboratory of Organic Chemistry; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Laurent Ruhlmann
- Laboratoire d'Électrochimie et Chimie Physique du Corps Solide, Institut de Chimie de Strasbourg; Université de Strasbourg; 4 rue Blaise Pascal, CS 90032 67081 Strasbourg France
| | - Corinne Boudon
- Laboratoire d'Électrochimie et Chimie Physique du Corps Solide, Institut de Chimie de Strasbourg; Université de Strasbourg; 4 rue Blaise Pascal, CS 90032 67081 Strasbourg France
| | - Oliver S. Wenger
- Department of Chemistry; University of Basel; St. Johanns-Ring 19 4056 Basel Switzerland
| | - Anton Savitsky
- Max Planck Institute for Chemical Energy Conversion; Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion; Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
| | - François Diederich
- Laboratory of Organic Chemistry; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
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Morales-Rivera CA, Floreancig PE, Liu P. Predictive Model for Oxidative C–H Bond Functionalization Reactivity with 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone. J Am Chem Soc 2017; 139:17935-17944. [DOI: 10.1021/jacs.7b08902] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | - Paul E. Floreancig
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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40
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Kim B, Storch G, Banerjee G, Mercado BQ, Castillo-Lora J, Brudvig GW, Mayer JM, Miller SJ. Stereodynamic Quinone-Hydroquinone Molecules That Enantiomerize at sp 3-Carbon via Redox-Interconversion. J Am Chem Soc 2017; 139:15239-15244. [PMID: 28931280 DOI: 10.1021/jacs.7b09176] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Since the discovery of molecular chirality, nonsuperimposable mirror-image organic molecules have been found to be essential across biological and chemical processes and increasingly in materials science. Generally, carbon centers containing four different substituents are configurationally stable, unless bonds to the stereogenic carbon atom are broken and re-formed. Herein, we describe sp3-stereogenic carbon-bearing molecules that dynamically isomerize, interconverting between enantiomers without cleavage of a constituent bond, nor through remote functional group migration. The stereodynamic molecules were designed to contain a pair of redox-active substituents, quinone and hydroquinone groups, which allow the enantiomerization to occur via redox-interconversion. In the presence of an enantiopure host, these molecules undergo a deracemization process that allows observation of enantiomerically enriched compounds. This work reveals a fundamentally distinct enantiomerization pathway available to chiral compounds, coupling redox-interconversion to chirality.
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Affiliation(s)
- Byoungmoo Kim
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Golo Storch
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Gourab Banerjee
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Brandon Q Mercado
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Janelle Castillo-Lora
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Gary W Brudvig
- 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
| | - Scott J Miller
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
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Yamaguchi K, Murai T, Kutsumizu S, Miwa Y, Ebihara M, Guo J, Tokitoh N. Experimental and Theoretical Examination of the Radical Cations Obtained from the Chemical and Electrochemical Oxidation of 5-Aminothiazoles. ChemistryOpen 2017; 6:282-287. [PMID: 28413765 PMCID: PMC5390811 DOI: 10.1002/open.201700016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Indexed: 11/11/2022] Open
Abstract
Chemical or electrochemical one-electron oxidation of 5-N-arylaminothiazoles was found to afford stable radical cations. For chemical oxidation, 1 equivalent of [(4-BrC6H4)3N][SbCl6] (Magic Blue, MB) was added to CH2Cl2 solutions of the thiazoles, and the thus-obtained radicals showed light absorption in the near-infrared region. Electrochemical oxidation also led to bathochromic shifts in the absorption bands, and the obtained spectra were similar to those derived from the chemically oxidized species. These radicals afforded electron paramagnetic resonance (EPR) spectra that are consistent with the notion of stable nitrogen radicals (half-life≤385 h). The EPR spectrum of a thiazole containing 4-dimethylaminophenyl groups on the nitrogen atom at the 5-position changed significantly upon adding >3 equivalents of MB. Details of the electronic structures of the experimentally obtained radical cations were generated from theoretical calculations.
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Affiliation(s)
- Kirara Yamaguchi
- Department of Chemistry and Biomolecular Science, Faculty of EngineeringGifu University, YanagidoGifu501–1193Japan
| | - Toshiaki Murai
- Department of Chemistry and Biomolecular Science, Faculty of EngineeringGifu University, YanagidoGifu501–1193Japan
| | - Shoichi Kutsumizu
- Department of Chemistry and Biomolecular Science, Faculty of EngineeringGifu University, YanagidoGifu501–1193Japan
| | - Yohei Miwa
- Department of Chemistry and Biomolecular Science, Faculty of EngineeringGifu University, YanagidoGifu501–1193Japan
| | - Masahiro Ebihara
- Department of Chemistry and Biomolecular Science, Faculty of EngineeringGifu University, YanagidoGifu501–1193Japan
| | - Jing‐Dong Guo
- Institute for Chemical ResearchKyoto University, Gokasho UjiKyoto611-0011Japan
| | - Norihiro Tokitoh
- Institute for Chemical ResearchKyoto University, Gokasho UjiKyoto611-0011Japan
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42
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Li WB, Yao QX, Sun L, Yang XD, Guo RY, Zhang J. A viologen-based coordination polymer exhibiting high sensitivity towards various light sources. CrystEngComm 2017. [DOI: 10.1039/c6ce02496c] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Rusch F, Schober JC, Brasholz M. Visible-Light Photocatalytic Aerobic Benzylic C(sp3
)−H Oxygenations with the 3
DDQ*/tert
-Butyl Nitrite Co-catalytic System. ChemCatChem 2016. [DOI: 10.1002/cctc.201600704] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Fabian Rusch
- Department of Chemistry; Institute of Organic Chemistry; University of Hamburg; Martin-Luther-King-Platz 6 20146 Hamburg Germany
| | - Jan-Christian Schober
- Department of Chemistry; Institute of Organic Chemistry; University of Hamburg; Martin-Luther-King-Platz 6 20146 Hamburg Germany
| | - Malte Brasholz
- Department of Chemistry; Institute of Organic Chemistry; University of Hamburg; Martin-Luther-King-Platz 6 20146 Hamburg Germany
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45
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Nepal B, Scheiner S. Enhancing the Reduction Potential of Quinones via Complex Formation. J Org Chem 2016; 81:4316-24. [PMID: 27135719 DOI: 10.1021/acs.joc.6b00755] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Quantum calculations are used to study the manner in which quinones interact with proton-donating molecules. For neutral donors, a stacked geometry is favored over a H-bond structure. The former is stabilized by charge transfers from the N or O lone pairs to the quinone's π* orbitals. Following the addition of an electron to the quinone, the radical anion forms strong H-bonded complexes with the various donors. The presence of the donor enhances the electron affinity of the quinone. This enhancement is on the order of 15 kcal/mol for neutral donors, but up to as much as 85 kcal/mol for a cationic donor. The increase in electron affinity is larger for electron-rich quinones than for their electron-deficient counterparts, containing halogen substituents. Similar trends are in evidence when the systems are immersed in aqueous solvent.
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Affiliation(s)
- Binod Nepal
- Department of Chemistry and Biochemistry, Utah State University , Logan, Utah 84322-0300, United States
| | - Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University , Logan, Utah 84322-0300, United States
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