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Haaf S, Engels E, Kaifer E, Himmel HJ. Hexaguanidino-Triptycenes and Triphenylenes: Electronic Coupling in Molecules Containing Three Redox-Active o-Diguanidinobenzene Units Connected either Directly or Interacting Through Homoconjugation. Chemistry 2024; 30:e202301903. [PMID: 37815019 DOI: 10.1002/chem.202301903] [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: 06/15/2023] [Revised: 09/22/2023] [Accepted: 10/10/2023] [Indexed: 10/11/2023]
Abstract
Novel redox-active hexaguanidine molecules with multiple redox states were synthesized by connecting three o-diguanidinobenzene units. In 2,3,6,7,14,15-hexaguanidino-triptycenes, the three redox-active o-diguanidinobenzene units are connected through C-C bonds to the sp3 -hybridized bridgehead C atoms, and in 2,3,6,7,10,11-hexaguanidino-triphenylenes they are directly connected. The connectivity difference leads to different electronic coupling between the three redox-active o-diguanidinobenzene units, with homoconjugation being present in the triptycene, but not in the triphenylene compounds. Motivated by the appearance of an intense low-energy electronic transition, we especially analysed the effect of homoconjugation on the electronic structure and charge delocalization in the dicationic redox state of the triptycene derivatives. Then, several trinuclear high-spin cobalt (and copper) complexes were synthesized with the triphenylene and triptycene ligands, and the magnetic coupling and redox properties analysed. By choice of the coligands (hexafluoroacetylacetonate, trifluoroacetylacetonate and acetylacetonate), oxidation could be switched between metal- and ligand-centered redox events, leading to drastic changes in the magnetic or optical properties, especially as a consequence of homoconjugation in the triptycene derivatives.
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Affiliation(s)
- Sebastian Haaf
- Inorganic Chemistry, Ruprecht-Karls University Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Eliane Engels
- Inorganic Chemistry, Ruprecht-Karls University Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Elisabeth Kaifer
- Inorganic Chemistry, Ruprecht-Karls University Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hans-Jörg Himmel
- Inorganic Chemistry, Ruprecht-Karls University Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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2
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Wild U, Hübner O, Meiners P, Kaifer E, Enders M, Himmel HJ. Intramolecular Through-Space Double-Electron Transfer Between A Pair of Redox-Active Guanidine Units Aligned by Dithiolate Bridges. Chemistry 2023; 29:e202302418. [PMID: 37606189 DOI: 10.1002/chem.202302418] [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: 07/27/2023] [Revised: 08/22/2023] [Accepted: 08/22/2023] [Indexed: 08/23/2023]
Abstract
Using unconventional synthesis protocols, two redox-active triguanidine units are connected by a dithiolate bridge, aligning the two redox-active units in close proximity. The reduced, neutral and the tetracationic redox states with two dicationic triguanidine units are isolated and fully characterized. Then, the dicationic redox states are prepared by mixing the neutral and tetracationic molecules. At low temperatures, the dications are diamagnetic (singlet ground state) with two different triguanidine units (neutral and dicationic). At room temperature, the triplet state with two radical monocationic triguanidine units is populated. At low temperature (210 K), chemical exchange by intramolecular through-space electron-transfer between the two triguanidine units is evidenced by EXSY NMR spectroscopy. Intramolecular through-space transfer of two electrons from the neutral to the dicationic triguanidine unit is accompanied by migration of the counterions in opposite direction. The rate of double-electron transfer critically depends on the bridge. No electron-transfer is measured in the absence of a bridge (in a mixture of one dicationic and one neutral triguanidine), and relatively slow electron transfer if the bridge does not allow the two triguanidine units to approach each other close enough. The results give detailed, quantitative insight into the factors that influence intramolecular through-space double-electron-transfer processes.
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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
| | - Paul Meiners
- 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
| | - Markus Enders
- 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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3
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Hua DH, Morita S, Ren Z, Gorla L, Tong Z, Edouarzin E, Averkiev B, Day VW. Indication of Pd–C or Cu–C Intermediates in Bimetallic Nanoclusters During Pd/Au-PVP- or Cu/Au-PVP-Catalyzed Oxidations of endo-4-Oxatricyclo[5.2.1.02,6]-8-decene and Tetrahydro-γ-carbolines. SYNTHESIS-STUTTGART 2022; 55:1227-1240. [PMID: 37151600 PMCID: PMC10162490 DOI: 10.1055/a-2001-6888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
AbstractCatalytic oxidation of tricyclic endo-norbornene-fused tetrahydrofuran with the bimetallic nanocluster Cu/Au-PVP in the presence of H2O2 or t-BuOOH as the oxidant leads to C–H bond oxidation adjacent to the ether function to give 4-oxa-tricyclo[5.2.1.0]-8,9-exo-epoxydecane, however, oxidation with Pd/Au-PVP takes place at the C=C double bond to give the same epoxide and the oxidative three-bond forming dimeric product, dodecahydro-1,4:6,9-dimethanodibenzofurano[2,3-b:7,8-b′]bisoxolane. Formation of the latter product suggests the involvement of a reactive Pd–C intermediate. Similarly, oxidative C–C bond-forming reactions are observed in cycloaddition reactions of N2-Boc-1,2,3,4-tetrahydro-γ-carbolines and 2,3-dihydroxybenzoic acid with Cu/Au-PVP (2–5 mol%) and H2O2 at 25 °C, providing two-bond-forming [4+2] cycloadducts. Under similar reaction conditions, Pd/Au-PVP did not produce the corresponding cycloadduct, indicating a need for complexation between Cu and the carboxylic acid group of 2,3-dihydroxybenzoic acid and the allylic amine function of the γ-carbolines during the cyclization reaction. The reported intermolecular coupling reactions using Pd/Au-PVP or Cu/Au-PVP nanocluster catalysts under oxidative conditions at 25 °C are unprecedented.
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Affiliation(s)
- Duy H. Hua
- Department of Chemistry, Kansas State University
| | | | - Zhaoyang Ren
- Department of Chemistry, Kansas State University
| | | | - Zongbo Tong
- Department of Chemistry, Kansas State University
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4
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A cobalt redox switch driving alcohol dehydrogenation by redox coupled molecular swing. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.06.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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5
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Wild U, Hübner O, Enders M, Kaifer E, Himmel HJ. Connecting Organic Redox‐Active Building Blocks Through Mild Non‐Catalytic C‐H Activation. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ute Wild
- Ruprecht Karls Universitat Heidelberg Fakultat fur Chemie und Geowissenschaften Chemistry GERMANY
| | - Olaf Hübner
- Ruprecht Karls Universitat Heidelberg Fakultat fur Chemie und Geowissenschaften Chemistry GERMANY
| | - Markus Enders
- Ruprecht Karls Universitat Heidelberg Fakultat fur Chemie und Geowissenschaften Chemistry GERMANY
| | - Elisabeth Kaifer
- Ruprecht Karls Universitat Heidelberg Fakultat fur Chemie und Geowissenschaften Chemistry GERMANY
| | - Hans-Jörg Himmel
- Ruprecht-Karls-Universität Heidelberg Institut für Anorganische Chemie Im Neuenheimer Feld 270 69120 Heidelberg GERMANY
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6
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Steuer L, Kaifer E, Himmel HJ. Redox‐Active Dendrimer‐Like Oligoguanidines and Their Use in a Proton‐Coupled Electron Transfer Reaction. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Lena Steuer
- Ruprecht Karls Universitat Heidelberg Fakultat fur Chemie und Geowissenschaften Chemistry GERMANY
| | - Elisabeth Kaifer
- Ruprecht Karls Universitat Heidelberg Fakultat fur Chemie und Geowissenschaften Chemistry GERMANY
| | - Hans-Jörg Himmel
- Ruprecht-Karls-Universität Heidelberg Institut für Anorganische Chemie Im Neuenheimer Feld 270 69120 Heidelberg GERMANY
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7
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Volpato GA, Colusso E, Paoloni L, Forchetta M, Sgarbossa F, Cristino V, Lunardon M, Berardi S, Caramori S, Agnoli S, Sabuzi F, Umari P, Martucci A, Galloni P, Sartorel A. Artificial photosynthesis: photoanodes based on polyquinoid dyes onto mesoporous tin oxide surface. Photochem Photobiol Sci 2021; 20:1243-1255. [PMID: 34570354 DOI: 10.1007/s43630-021-00097-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/30/2021] [Indexed: 12/27/2022]
Abstract
Dye-sensitized photoelectrochemical cells represent an appealing solution for artificial photosynthesis, aimed at the conversion of solar light into fuels or commodity chemicals. Extensive efforts have been directed towards the development of photoelectrodes combining semiconductor materials and organic dyes; the use of molecular components allows to tune the absorption and redox properties of the material. Recently, we have reported the use of a class of pentacyclic quinoid organic dyes (KuQuinone) chemisorbed onto semiconducting tin oxide as photoanodes for water oxidation. In this work, we investigate the effect of the SnO2 semiconductor thickness and morphology and of the dye-anchoring group on the photoelectrochemical performance of the electrodes. The optimized materials are mesoporous SnO2 layers with 2.5 μm film thickness combined with a KuQuinone dye with a 3-carboxylpropyl-anchoring chain: these electrodes achieve light-harvesting efficiency of 93% at the maximum absorption wavelength of 533 nm, and photocurrent density J up to 350 μA/cm2 in the photoelectrochemical oxidation of ascorbate, although with a limited incident photon-to-current efficiency of 0.075%. Calculations based on the density functional theory (DFT) support the role of the reduced species of the KuQuinone dye via a proton-coupled electron transfer as the competent species involved in the electron transfer to the tin oxide semiconductor. Finally, a preliminary investigation of the photoelectrodes towards benzyl alcohol oxidation is presented, achieving photocurrent density up to 90 μA/cm2 in acetonitrile in the presence of N-hydroxysuccinimide and pyridine as redox mediator and base, respectively. These results support the possibility of using molecular-based materials in synthetic photoelectrochemistry.
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Affiliation(s)
- Giulia Alice Volpato
- Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, 35131, Padua, Italy
| | - Elena Colusso
- Department of Industrial Engineering and INSTM, University of Padova, F. Marzolo 9, 35131, Padua, Italy
| | - Lorenzo Paoloni
- Department of Physics and Astronomy, University of Padova, Via F. Marzolo 8, 35131, Padua, Italy
| | - Mattia Forchetta
- Department of Chemical Science and Technologies, University of Rome "Tor Vergata", Via della Ricerca Scientifica, snc, 00133, Rome, Italy
| | - Francesco Sgarbossa
- Department of Physics and Astronomy, University of Padova, Via F. Marzolo 8, 35131, Padua, Italy
| | - Vito Cristino
- Department of Chemical and Pharmaceutical Sciences, Centro Interuniversitario per la Conversione Chimica dell'Energia Solare (SolarChem), Sez. di Ferrara, University of Ferrara, Via L. Borsari 46, 44121, Ferrara, Italy
| | - Marco Lunardon
- Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, 35131, Padua, Italy
| | - Serena Berardi
- Department of Chemical and Pharmaceutical Sciences, Centro Interuniversitario per la Conversione Chimica dell'Energia Solare (SolarChem), Sez. di Ferrara, University of Ferrara, Via L. Borsari 46, 44121, Ferrara, Italy
| | - Stefano Caramori
- Department of Chemical and Pharmaceutical Sciences, Centro Interuniversitario per la Conversione Chimica dell'Energia Solare (SolarChem), Sez. di Ferrara, University of Ferrara, Via L. Borsari 46, 44121, Ferrara, Italy
| | - Stefano Agnoli
- Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, 35131, Padua, Italy
| | - Federica Sabuzi
- Department of Chemical Science and Technologies, University of Rome "Tor Vergata", Via della Ricerca Scientifica, snc, 00133, Rome, Italy
| | - Paolo Umari
- Department of Physics and Astronomy, University of Padova, Via F. Marzolo 8, 35131, Padua, Italy.
| | - Alessandro Martucci
- Department of Industrial Engineering and INSTM, University of Padova, F. Marzolo 9, 35131, Padua, Italy.
| | - Pierluca Galloni
- Department of Chemical Science and Technologies, University of Rome "Tor Vergata", Via della Ricerca Scientifica, snc, 00133, Rome, Italy.
| | - Andrea Sartorel
- Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, 35131, Padua, Italy.
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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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Liu J, Guðmundsson A, Bäckvall J. Efficient Aerobic Oxidation of Organic Molecules by Multistep Electron Transfer. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202012707] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jie Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical Engineering Hunan University 410082 Changsha China
- Department of Organic Chemistry Arrhenius Laboratory Stockholm University SE-10691 Stockholm Sweden
| | - Arnar Guðmundsson
- Department of Organic Chemistry Arrhenius Laboratory Stockholm University SE-10691 Stockholm Sweden
| | - Jan‐E. Bäckvall
- Department of Organic Chemistry Arrhenius Laboratory Stockholm University SE-10691 Stockholm Sweden
- Department of Natural Sciences Mid Sweden University Holmgatan 10 SE-85170 Sundsvall Sweden
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10
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Liu J, Guðmundsson A, Bäckvall JE. Efficient Aerobic Oxidation of Organic Molecules by Multistep Electron Transfer. Angew Chem Int Ed Engl 2021; 60:15686-15704. [PMID: 33368909 PMCID: PMC9545650 DOI: 10.1002/anie.202012707] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Indexed: 12/17/2022]
Abstract
This Minireview presents recent important homogenous aerobic oxidative reactions which are assisted by electron transfer mediators (ETMs). Compared with direct oxidation by molecular oxygen (O2), the use of a coupled catalyst system with ETMs leads to a lower overall energy barrier via stepwise electron transfer. This cooperative catalytic process significantly facilitates the transport of electrons from the reduced form of the substrate‐selective redox catalyst (SSRCred) to O2, thereby increasing the efficiency of the aerobic oxidation. In this Minireview, we have summarized the advances accomplished in recent years in transition‐metal‐catalyzed as well as metal‐free aerobic oxidations of organic molecules in the presence of ETMs. In addition, the recent progress of photochemical and electrochemical oxidative functionalization using ETMs and O2 as the terminal oxidant is also highlighted. Furthermore, the mechanisms of these transformations are showcased.
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Affiliation(s)
- Jie Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, 410082, Changsha, China.,Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691, Stockholm, Sweden
| | - Arnar Guðmundsson
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691, Stockholm, Sweden
| | - Jan-E Bäckvall
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691, Stockholm, Sweden.,Department of Natural Sciences, Mid Sweden University, Holmgatan 10, SE-85170, Sundsvall, Sweden
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11
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Wild U, Walter P, Hübner O, Kaifer E, Himmel HJ. Evaluation of the Synthetic Scope and the Reaction Pathways of Proton-Coupled Electron Transfer with Redox-Active Guanidines in C-H Activation Processes. Chemistry 2020; 26:16504-16513. [PMID: 32893902 PMCID: PMC7756729 DOI: 10.1002/chem.202003424] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/04/2020] [Indexed: 11/28/2022]
Abstract
Proton‐coupled electron transfer (PCET) is currently intensively studied because of its importance in synthetic chemistry and biology. In recent years it was shown that redox‐active guanidines are capable PCET reagents for the selective oxidation of organic molecules. In this work, the scope of their PCET reactivity regarding reactions that involve C−H activation is explored and kinetic studies carried out to disclose the reaction mechanisms. Organic molecules with potential up to 1.2 V vs. ferrocenium/ferrocene are efficiently oxidized. Reactions are initiated by electron transfer, followed by slow proton transfer from an electron‐transfer equilibrium.
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Affiliation(s)
- Ute Wild
- Institut für Anorganische Chemie, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Petra Walter
- Institut für Anorganische Chemie, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Olaf Hübner
- Institut für Anorganische Chemie, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Elisabeth Kaifer
- Institut für Anorganische Chemie, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hans-Jörg Himmel
- Institut für Anorganische Chemie, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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12
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Santana AG, González CC. Tandem Radical Fragmentation/Cyclization of Guanidinylated Monosaccharides Grants Access to Medium-Sized Polyhydroxylated Heterocycles. Org Lett 2020; 22:8492-8495. [PMID: 33074675 DOI: 10.1021/acs.orglett.0c03091] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The fragmentation of anomeric alkoxyl radicals (ARF) and the subsequent cyclization promoted by hypervalent iodine provide an excellent method for the synthesis of guanidino-sugars. The methodology described herein is one of the few existing general methodologies for the formation of medium-sized exo- and endoguanidine-containing heterocycles presenting a high degree of oxygenation in their structure.
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Affiliation(s)
- Andrés G Santana
- Instituto de Productos Naturales y Agrobiología del C.S.I.C., Avenida Astrofísico Francisco Sánchez 3, 38206 La Laguna, Tenerife, Spain
| | - Concepción C González
- Instituto de Productos Naturales y Agrobiología del C.S.I.C., Avenida Astrofísico Francisco Sánchez 3, 38206 La Laguna, Tenerife, Spain
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13
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Berlinck RGS, Bernardi DI, Fill T, Fernandes AAG, Jurberg ID. The chemistry and biology of guanidine secondary metabolites. Nat Prod Rep 2020; 38:586-667. [PMID: 33021301 DOI: 10.1039/d0np00051e] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Covering: 2017-2019Guanidine natural products isolated from microorganisms, marine invertebrates and terrestrial plants, amphibians and spiders, represented by non-ribosomal peptides, guanidine-bearing polyketides, alkaloids, terpenoids and shikimic acid derived, are the subject of this review. The topics include the discovery of new metabolites, total synthesis of natural guanidine compounds, biological activity and mechanism-of-action, biosynthesis and ecological functions.
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Affiliation(s)
- Roberto G S Berlinck
- Instituto de Química de São Carlos, Universidade de São Paulo, CP 780, CEP 13560-970, São Carlos, SP, Brazil.
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Kantlehner W, Tiritiris I, Vettel M, Frey W. Orthoamide und Iminiumsalze, IIC. Darstellung von N-( ω-Ammonioalkyl)- N,N′,N′,N″,N″-peralkylierten Guanidiniumsalzen und N-( ω-Aminoalkyl)- N′,N′,N″,N″-tetramethylguanidinen. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2020. [DOI: 10.1515/znb-2019-0229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
N,N,N′,N′-Tetraalkylchlorformamidiniumchlorides 1a, b react with ω-dimethylaminoalkylamines 19, 20 to give mixtures of N-(ω-dimethylammonioalkyl)-guanidinium salts 12, 13 and N-(ω-dimethylaminoalkyl)-guanidinium salts 21, 22. These mixtures are transformed to mixtures of the ureas 15, 17 and N-(ω-dimethylaminoalkyl)-guanidines 23, 25 on treatment with aqueous sodium hydroxide. The reaction of N-(3-dimethylammoniopropyl)-guanidin 25a with dimethylsulfate in a molar ratio of 1:1 delivers a mixture of the N-(3-dimethylaminopropyl)-N,N,N′,N′,N″,N″-pentamethyl-guanidinium salt 29a and the N-(3-dimethylammoniopropyl)-N,N′,N′,N″,N″-pentamethyl-guanidinium-bis (methylsulfate) 33a. The action of dimethylsulfate on the guanidines 23a, 25a in a molar ratio of 2:1 affords the bisquarternary salts 32a, 33a. Alkylating reagents as methyliodide, benzylbromide, allylbromide and chloroacetonitrile attack N-(2-dimethylaminoethyl)-N′,N′,N″,N″-tetraethylguanidine (23b) in a molar ratio of 1:1 cleanly at the dimethylaminoethylgroup to give the ammonium salts 30a–d. As a strong base the guanidine 23b dehydrochlorinates β-Chlorpropionitrile and chloroacetone under formation of the guanidinium salt 21c. In contrast to this the reaction of ethyl bromoacetate with the N-(2-dimethylaminoethyl)guanidine 23b occurs at the guanidinogroup giving the guanidinium salt 28c. The methylation of the guanidinium chlorides 21a, 22a with dimethyl sulfate affords the bis-quaternary salts 35b, 36b with mixed anions. From the heterocyclic guanidines 14, 16 and the alkylating reagents benzylbromide and ethyl bromoacetate the heterocyclic guanidinium salts 37a, b, 39a, b can be obtained. The reactions with ethyl chloroformiate proceed in an analogous way giving the guanidinium salts 37c, 39c. The N-alkyl-N,N,N′,N′-tetramethyl-(3-ureidopropyl)guanidinium salts 41a, b can be prepared from the N′,N′,N″,N″-tetramethyl-N′′-(3-ureidopropyl) guanidine 17a and the alkylating compounds dimethyl sulfate and benzyl bromide. Several compounds obtained that way were transformed to the corresponding tetraphenyloborates and bis(tetraphenylborates), respectively.
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Affiliation(s)
- Willi Kantlehner
- Institut für Angewandte Forschung, Abteilung Technische Organische Synthesechemie und Katalyseforschung (TOSKA), Hochschule Aalen , Beethovenstr. 1 , D-73430 Aalen , Germany
- Institut für Organische Chemie, Universität Stuttgart , Pfaffenwaldring 55 , 70569 Stuttgart , Germany
| | - Ioannis Tiritiris
- Institut für Organische Chemie, Universität Stuttgart , Pfaffenwaldring 55 , 70569 Stuttgart , Germany
| | - Markus Vettel
- Institut für Organische Chemie, Universität Stuttgart , Pfaffenwaldring 55 , 70569 Stuttgart , Germany
| | - Wolfgang Frey
- Institut für Organische Chemie, Universität Stuttgart , Pfaffenwaldring 55 , 70569 Stuttgart , Germany
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15
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Wagner C, Kreis F, Popp D, Hübner O, Kaifer E, Himmel H. 1,2,4,5-Tetrakis(tetramethylguanidino)-3,6-diethynyl-benzenes: Fluorescent Probes, Redox-Active Ligands and Strong Organic Electron Donors. Chemistry 2020; 26:10336-10347. [PMID: 32368816 PMCID: PMC7497081 DOI: 10.1002/chem.202001557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/30/2020] [Indexed: 11/25/2022]
Abstract
In this work, the change of reactivity induced by the introduction of two para-ethynyl substituents (CCSi(iPr)3 or CCH) to the organic electron-donor 1,2,4,5-tetrakis(tetramethylguanidino)-benzene is evaluated. The redox-properties and redox-state dependent fluorescence are evaluated, and dinuclear CuI and CuII complexes synthesized. The Lewis-acidic B(C6 F5 )3 substitutes the proton of the ethynyl -CCH groups to give new anionic -CCB(C6 F5 )3 - substituents, leading eventually to a novel dianionic strong electron donor in its diprotonated form. Its two-electron oxidation with dioxygen in the presence of a copper catalyst yields the first redox-active guanidine that is neutral (instead of cationic) in its oxidized form.
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Affiliation(s)
- Conrad Wagner
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Franka Kreis
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Dennis Popp
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Olaf Hübner
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Elisabeth Kaifer
- 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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16
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Lohmeyer L, Kaifer E, Wadepohl H, Himmel H. 1,2,5,6-Tetrakis(guanidino)-Naphthalenes: Electron Donors, Fluorescent Probes and Redox-Active Ligands. Chemistry 2020; 26:5834-5845. [PMID: 32017282 PMCID: PMC7318682 DOI: 10.1002/chem.201905471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/23/2020] [Indexed: 01/07/2023]
Abstract
New redox-active 1,2,5,6-tetrakis(guanidino)-naphthalene compounds, isolable and storable in the neutral and deep-green dicationic redox states and oxidisable further in two one-electron steps to the tetracations, are reported. Protonation switches on blue fluorescence, with the fluorescence intensity (quantum yield) increasing with the degree of protonation. Reactions with N-halogenosuccinimides or N-halogenophthalimides led to a series of new redox-active halogeno- and succinimido-/phthalimido-substituted derivatives. These highly selective reactions are proposed to proceed via the tri- or tetracationic state as the intermediate. The derivatives are oxidised reversibly at slightly higher potentials than that of the unsubstituted compounds to dications and further to tri- and tetracations. The integration of redox-active ligands in the transition-metal complexes shifts the redox potentials to higher values and also allows reversible oxidation in two potentially separated one-electron steps.
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Affiliation(s)
- Lukas Lohmeyer
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Hubert Wadepohl
- 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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17
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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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18
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Walter P, Kaifer E, Herrmann H, Wadepohl H, Hübner O, Himmel H. Redox‐Active Guanidines with One or Two Guanidino Groups and Their Integration in Low‐Dimensional Perovskite Structures. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900975] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Petra Walter
- 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
| | - Hendrik Herrmann
- Anorganisch‐Chemisches Institut Ruprecht‐Karls‐Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Hubert Wadepohl
- 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
| | - Hans‐Jörg Himmel
- Anorganisch‐Chemisches Institut Ruprecht‐Karls‐Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
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19
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Schön F, Kaifer E, Himmel H. Catalytic Aerobic Phenol Homo‐ and Cross‐Coupling Reactions with Copper Complexes Bearing Redox‐Active Guanidine Ligands. Chemistry 2019; 25:8279-8288. [DOI: 10.1002/chem.201900583] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Indexed: 01/12/2023]
Affiliation(s)
- Florian Schön
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Hans‐Jörg Himmel
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
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20
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Wagner C, Hübner O, Kaifer E, Himmel HJ. Probing the Proton-Coupled Electron-Transfer (PCET) Reactivity of a Cross-Conjugated Cruciform Chromophore by Redox-State-Dependent Fluorescence. Chemistry 2019; 25:3781-3785. [PMID: 30688382 DOI: 10.1002/chem.201900268] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Indexed: 11/07/2022]
Abstract
Proton-coupled electron transfer (PCET) reactions are of great importance in synthetic chemistry and in biology, but the acquisition of kinetic information for these reactions is often difficult. Herein, we report the synthesis of a new PCET reagent, showing redox-state dependent fluorescence, by merging the concept of cross-conjugated cruciform chromophores with the strategy of imposing redox activity and Brønsted basicity to aromatic compounds by substitution with guanidino groups. The compound is isolated and characterized in all stable states-reduced, twofold and fourfold protonated and twofold oxidized-and then applied in PCET reactions by using its redox-state dependent fluorescence signal for kinetic measurements.
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Affiliation(s)
- Conrad Wagner
- Anorganisch-Chemisches Institut, Ruprecht-Karls-University of Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Olaf Hübner
- Anorganisch-Chemisches Institut, Ruprecht-Karls-University of Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches Institut, Ruprecht-Karls-University of Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hans-Jörg Himmel
- Anorganisch-Chemisches Institut, Ruprecht-Karls-University of Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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21
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Ortmeyer J, Vukadinovic Y, Neuba A, Flörke U, Henkel G. Combining a Phenanthroline Moiety with Peralkylated Guanidine Residues: Homometallic Cu
II
, Ni
II
and Zn
II
Halide Complexes with Site‐Differentiating Janus Head Ligands. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Jochen Ortmeyer
- Fakultät für Naturwissenschaften Department Chemie Universität Paderborn Warburger Strasse 100 33098 Paderborn Germany
| | - Yannik Vukadinovic
- Fakultät für Naturwissenschaften Department Chemie Universität Paderborn Warburger Strasse 100 33098 Paderborn Germany
| | - Adam Neuba
- Fakultät für Naturwissenschaften Department Chemie Universität Paderborn Warburger Strasse 100 33098 Paderborn Germany
| | - Ulrich Flörke
- Fakultät für Naturwissenschaften Department Chemie Universität Paderborn Warburger Strasse 100 33098 Paderborn Germany
| | - Gerald Henkel
- Fakultät für Naturwissenschaften Department Chemie Universität Paderborn Warburger Strasse 100 33098 Paderborn Germany
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22
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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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23
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Stone IB, Jermaks J, MacMillan SN, Lambert TH. The Hydrazine-O 2 Redox Couple as a Platform for Organocatalytic Oxidation: Benzo[c]cinnoline-Catalyzed Oxidation of Alkyl Halides to Aldehydes. Angew Chem Int Ed Engl 2018; 57:12494-12498. [PMID: 30016572 DOI: 10.1002/anie.201807134] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 07/13/2018] [Indexed: 11/07/2022]
Abstract
An organocatalytic oxidation platform that capitalizes on the capacity of hydrazines to undergo rapid autoxidation to diazenes is described. Commercially available benzo[c]cinnoline is shown to catalyze the oxidation of alkyl halides to aldehydes in a novel mechanistic paradigm involving nucleophilic attack, prototropic shift, and hydrolysis. The hydrolysis and reoxidation events occur readily with only adventitious oxygen and water. A survey of the scope of viable substrates is shown along with mechanistic and computational studies that give insight into this mode of catalysis.
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Affiliation(s)
- Ilana B Stone
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Janis Jermaks
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Samantha N MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Tristan H Lambert
- Department of Chemistry, Columbia University, New York, NY, 10027, USA.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
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24
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Stone IB, Jermaks J, MacMillan SN, Lambert TH. The Hydrazine–O
2
Redox Couple as a Platform for Organocatalytic Oxidation: Benzo[
c
]cinnoline‐Catalyzed Oxidation of Alkyl Halides to Aldehydes. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201807134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ilana B. Stone
- Department of Chemistry Columbia University New York NY 10027 USA
| | - Janis Jermaks
- Department of Chemistry and Chemical Biology Cornell University Ithaca NY 14853 USA
| | | | - Tristan H. Lambert
- Department of Chemistry Columbia University New York NY 10027 USA
- Department of Chemistry and Chemical Biology Cornell University Ithaca NY 14853 USA
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25
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Schneider S, Brohmann M, Lorenz R, Hofstetter YJ, Rother M, Sauter E, Zharnikov M, Vaynzof Y, Himmel HJ, Zaumseil J. Efficient n-Doping and Hole Blocking in Single-Walled Carbon Nanotube Transistors with 1,2,4,5-Tetrakis(tetramethylguanidino)ben-zene. ACS NANO 2018; 12:5895-5902. [PMID: 29787248 DOI: 10.1021/acsnano.8b02061] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Efficient, stable, and solution-based n-doping of semiconducting single-walled carbon nanotubes (SWCNTs) is highly desired for complementary circuits but remains a significant challenge. Here, we present 1,2,4,5-tetrakis(tetramethylguanidino)benzene (ttmgb) as a strong two-electron donor that enables the fabrication of purely n-type SWCNT field-effect transistors (FETs). We apply ttmgb to networks of monochiral, semiconducting (6,5) SWCNTs that show intrinsic ambipolar behavior in bottom-contact/top-gate FETs and obtain unipolar n-type transport with 3-5-fold enhancement of electron mobilities (approximately 10 cm2 V-1 s-1), while completely suppressing hole currents, even at high drain voltages. These n-type FETs show excellent on/off current ratios of up to 108, steep subthreshold swings (80-100 mV/dec), and almost no hysteresis. Their excellent device characteristics stem from the reduction of the work function of the gold electrodes via contact doping, blocking of hole injection by ttmgb2+ on the electrode surface, and removal of residual water from the SWCNT network by ttmgb protonation. The ttmgb-treated SWCNT FETs also display excellent environmental stability under bias stress in ambient conditions. Complementary inverters based on n- and p-doped SWCNT FETs exhibit rail-to-rail operation with high gain and low power dissipation. The simple and stable ttmgb molecule thus serves as an example for the larger class of guanidino-functionalized aromatic compounds as promising electron donors for high-performance thin film electronics.
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