1
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Qi JQ, Suo W, Liu J, Sun S, Jiao L, Guo X. Direct Observation of All Open-Shell Intermediates in a Photocatalytic Cycle. J Am Chem Soc 2024; 146:7140-7145. [PMID: 38466365 DOI: 10.1021/jacs.3c14471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Molecular photocatalysis has shown tremendous success in sustainable energy and chemical synthesis. However, visualizing the transient open-shell intermediates in photocatalysis is a significant and long-standing challenge. By employing our recently developed innovative time-resolved electron paramagnetic resonance technique, we directly observed all radicals and radical ions involved in the photocatalytic addition of pempidine to tert-butyl acrylate. The full picture of the photocatalytic cycle is vividly illustrated by the fine structures, chemical kinetics, and dynamic spin polarization of all open-shell intermediates directly observed in this prototypical system. Given the universality of this methodology, we believe it greatly empowers the research paradigm of direct observation in both photocatalysis and radical chemistry.
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Affiliation(s)
- Jian-Qing Qi
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Weiqun Suo
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jing Liu
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Songtao Sun
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Lei Jiao
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Xingwei Guo
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing 100084, China
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2
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Schwengers SA, Gerosa GG, Amatov T, Yasukawa N, Brunen S, Leutzsch M, Mitschke B, Shevchenko GA, List B. Direct Regioselective Dehydrogenation of α-Substituted Cyclic Ketones. Angew Chem Int Ed Engl 2023; 62:e202307081. [PMID: 37337974 DOI: 10.1002/anie.202307081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 06/21/2023]
Abstract
We disclose a highly regioselective, catalytic one-step dehydrogenation of α-substituted cyclic ketones in the presence of 2,3-dichlorobenzo-5,6-dicyano-1,4-benzoquinone (DDQ). The high regioselectivity originates from a phosphoric acid-catalyzed enolization, selectively affording the thermodynamically preferred enol, followed by the subsequent oxidation event. Our method provides reliable access to several α-aryl and α-alkyl substituted α,β-unsaturated ketones.
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Affiliation(s)
| | | | - Tynchtyk Amatov
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Naoki Yasukawa
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Sebastian Brunen
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Benjamin Mitschke
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Grigory André Shevchenko
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Benjamin List
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
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3
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Wang M, Wang C, Xie X, Pan D, Liu L, Chen Q, Li Z, Zhang Q, Xu Z. Non-classical C-saccharide linkage of dehydroalanine: synthesis of C-glycoamino acids and C-glycopeptides. Chem Commun (Camb) 2023; 59:3305-3308. [PMID: 36847114 DOI: 10.1039/d2cc06653j] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Herein, a non-classical C-saccharide linkage is reported via a C5 radical of pentose or C6 radical of hexose addition to Michael acceptors. C(sp3)-S cleaved glycosyl thianthrenium salts are developed as the glycosyl radical agents. The reaction provides an efficient toolkit to synthesize β-glycosyl substituted unnatural amino acids as well as for the late-stage C-saccharide modification of peptides.
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Affiliation(s)
- Mengran Wang
- Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou 730000, China. .,Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Chao Wang
- Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou 730000, China. .,Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Xiuling Xie
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Da Pan
- School of Pharmacy, Lanzhou University, Lanzhou 730000, China
| | - Liangyu Liu
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Qiao Chen
- School of Pharmacy, Lanzhou University, Lanzhou 730000, China
| | - Zhixuan Li
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Qi Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Zhaoqing Xu
- Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066, Lanzhou 730000, China. .,Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
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4
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Mulks FF, Melaimi M, Yan X, Baik MH, Bertrand G. How To Enhance the Efficiency of Breslow Intermediates for SET Catalysis. J Org Chem 2023; 88:2535-2542. [PMID: 36719963 DOI: 10.1021/acs.joc.2c02978] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Oxidative carbene organocatalysis, which proceeds via single electron transfer (SET) pathways, has been limited by the moderately reducing properties of deprotonated Breslow intermediates BI-s derived from thiazol-2-ylidene 1 and 1,2,4-triazolylidene 2. Using computational methods, we assess the redox potentials of BI-s based on ten different types of known stable carbenes and report our findings concerning the key parameters influencing the steps of the catalytic cycle. From the calculated values of the first oxidation potential of BI-s derived from carbenes 1 to 10, it appears that, apart from the diamidocarbene 7, all the others are more reducing than thiazol-2-ylidene 1 and the 1,2,4-triazolylidene 2. We observed that while the reducing power of BI-s significantly decreases with increasing solvent polarity, the redox potential of the oxidant can increase at a greater rate, thus facilitating the reaction. The cation, associated with the base, also plays an important role when a nonpolar solvent is used; large and weakly coordinating cations such as Cs+ are beneficial. The radical-radical coupling step is probably the most challenging step due to both electronic and steric constraints. Based on our results, we predict that mesoionic carbene 3 and abnormal NHC 4 are the most promising candidates for oxidative carbene organocatalysis.
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Affiliation(s)
- Florian F Mulks
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.,UCSD-CNRS Joint Research Chemistry Laboratory (UMI 3555), Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, United States
| | - Mohand Melaimi
- UCSD-CNRS Joint Research Chemistry Laboratory (UMI 3555), Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, United States
| | - Xiaoyu Yan
- Department of Chemistry, Renmin University of China, Beijing 100872, People's Republic of China
| | - Mu-Hyun Baik
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Guy Bertrand
- UCSD-CNRS Joint Research Chemistry Laboratory (UMI 3555), Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, United States
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5
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Devarahosahalli Veeranna K, Kanti Das K, Baskaran S. Reversal of polarity by catalytic SET oxidation: synthesis of azabicyclo[ m. n.0]alkanes via chemoselective reduction of amidines. Org Biomol Chem 2021; 19:4054-4059. [PMID: 33885121 DOI: 10.1039/d1ob00416f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A one-pot catalytic method has been developed for the stereoselective synthesis of cyclopropane-fused cyclic amidines using CuBr2/K2S2O8 as an efficient single electron transfer (SET) oxidative system. The generality of this mild method is demonstrated with a wide variety of substrates to furnish pharmaceutically important amidines containing aza-bicyclic and novel aza-tricyclic frameworks in very good yields. A chemoselective reduction of cyclic amidines to 2-/3-azabicyclo[m.n.0]alkanes and octahydroindoles has been developed using a NaBH4/I2 reagent system. The synthetic scope of the chemoselective reduction of the amidine functionality has been exemplified in the stereoselective synthesis of an iminosugar based (±)-epiquinamide analogue.
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Affiliation(s)
| | - Kanak Kanti Das
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600 036, India.
| | - Sundarababu Baskaran
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600 036, India.
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6
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Rathnayake MD, Weaver JD. Coupling Photocatalysis and Substitution Chemistry to Expand and Normalize Redox-Active Halides. Org Lett 2021; 23:2036-2041. [PMID: 33634699 DOI: 10.1021/acs.orglett.1c00173] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Photocatalysis can generate radicals in a controlled fashion and has become an important synthetic strategy. However, limitations due to the reducibility of alkyl halides prevent their broader implementation. Herein we explore the use of nucleophiles that can substitute the halide and serve as an electron capture motif that normalize the variable redox potentials across substrates. When used with photocatalysis, bench-stable, commercially available collidinium salts prove to be excellent radical precursors with a broad scope.
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Affiliation(s)
- Manjula D Rathnayake
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences, Stillwater, Oklahoma 74078, United States
| | - Jimmie D Weaver
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences, Stillwater, Oklahoma 74078, United States
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7
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Fang Y, Yadav I, Osterloh WR, Chaudhri N, Sankar M, Kadish KM. Electrochemistry of Tri‐substituted Porphyrins with
β
‐Appended Ethyl Acetoacetate and Acetylacetone in Neutral and Basic Nonaqueous Solvents. ChemElectroChem 2020. [DOI: 10.1002/celc.202000191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yuanyuan Fang
- School of Chemistry and Chemical Engineering Jiangsu University Zhenjiang 212013 China
- Department of Chemistry University of Houston Houston, TX 77204-5003 USA
| | - Inderpal Yadav
- Department of Chemistry Indian Institute of Technology Roorkee Roorkee 247667 India
| | - W. Ryan Osterloh
- Department of Chemistry University of Houston Houston, TX 77204-5003 USA
| | - Nivedita Chaudhri
- Department of Chemistry Indian Institute of Technology Roorkee Roorkee 247667 India
| | - Muniappan Sankar
- Department of Chemistry Indian Institute of Technology Roorkee Roorkee 247667 India
| | - Karl M. Kadish
- Department of Chemistry University of Houston Houston, TX 77204-5003 USA
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8
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Kuo JL, Gunasekara T, Hansen A, Vibbert HB, Bohle F, Norton JR, Grimme S, Quinlivan PJ. Thermodynamics of H+/H•/H–/e– Transfer from [CpV(CO)3H]−: Comparisons to the Isoelectronic CpCr(CO)3H. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00586] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jonathan L. Kuo
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, United States
| | - Thilina Gunasekara
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, United States
| | - Andreas Hansen
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms Universität Bonn, Beringstraße 4, 53115 Bonn, Germany
| | - Hunter B. Vibbert
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, United States
| | - Fabian Bohle
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms Universität Bonn, Beringstraße 4, 53115 Bonn, Germany
| | - Jack R. Norton
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, United States
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms Universität Bonn, Beringstraße 4, 53115 Bonn, Germany
| | - Patrick J. Quinlivan
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, United States
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9
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Regnier V, Romero EA, Molton F, Jazzar R, Bertrand G, Martin D. What Are the Radical Intermediates in Oxidative N-Heterocyclic Carbene Organocatalysis? J Am Chem Soc 2018; 141:1109-1117. [PMID: 30561990 DOI: 10.1021/jacs.8b11824] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The oxidation of the Breslow intermediate resulting from the addition of an N-heterocyclic carbene (NHC) to benzaldehyde triggers a fast deprotonation, followed by a second electron transfer, directly affording the corresponding acylium at E > -0.8 V (versus Fc/Fc+). Similarly, the oxidation of the cinnamaldehyde analogue occurs at an even higher potential and is not a reversible electrochemical process. As a whole, and contrary to previous beliefs, it is demonstrated that Breslow intermediates, which are the key intermediates in NHC-catalyzed transformations of aldehydes, cannot undergo a single electron transfer (SET) with mild oxidants ( E < -1.0 V). Moreover, the corresponding enol radical cations are ruled out as relevant intermediates. It is proposed that oxidative NHC-catalyzed radical transformations of enals proceed either through SET from the corresponding electron-rich enolate or through coupled electron-proton transfer from the enol, in any case generating neutral capto-dative radicals. Relevant electrochemical surrogates of these paramagnetic species have been isolated.
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Affiliation(s)
| | - Erik A Romero
- UMI CNRS 3555, Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093-0343 , United States
| | - Florian Molton
- Univ. Grenoble Alpes , CNRS, DCM , 38000 Grenoble , France
| | - Rodolphe Jazzar
- UMI CNRS 3555, Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093-0343 , United States
| | - Guy Bertrand
- UMI CNRS 3555, Department of Chemistry and Biochemistry , University of California, San Diego , La Jolla , California 92093-0343 , United States
| | - David Martin
- Univ. Grenoble Alpes , CNRS, DCM , 38000 Grenoble , France
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10
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Cinar ME, Lal M, Deiseroth HJ, Schlirf J, Schmittel M. Detection and follow-up reactions of distonic β
, β
-dimesityl enol radical cations containing nitrogen heterocyclic bases. J PHYS ORG CHEM 2018. [DOI: 10.1002/poc.3865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- M. Emin Cinar
- Department Chemie-Biologie; Universität Siegen; Siegen Germany
| | - Mukul Lal
- Department Chemie-Biologie; Universität Siegen; Siegen Germany
| | | | - Jens Schlirf
- Department Chemie-Biologie; Universität Siegen; Siegen Germany
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11
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Shevchenko GA, Oppelaar B, List B. Enolkatalyse ermöglicht eine unerwartete α‐Oxidation zyklischer Ketone mit 1,4‐Benzochinonen. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804445] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Grigory A. Shevchenko
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Deutschland
| | - Barry Oppelaar
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Deutschland
| | - Benjamin List
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Deutschland
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12
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An Unexpected α‐Oxidation of Cyclic Ketones with 1,4‐Benzoquinone by Enol Catalysis. Angew Chem Int Ed Engl 2018; 57:10756-10759. [DOI: 10.1002/anie.201804445] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Indexed: 12/24/2022]
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13
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Bucher G, Lal M, Rana A, Schmittel M. Fragmentation of a dioxolanyl radical via nonstatistical reaction dynamics: characterization of the vinyloxy radical by ns time-resolved laser flash photolysis. Phys Chem Chem Phys 2018; 20:19819-19828. [PMID: 30033465 DOI: 10.1039/c8cp03311k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photochemistry of two Barton esters, one derived from a dioxolane carboxylic acid and the other from pivalic acid, was investigated by product analysis and nanosecond laser flash photolysis (LFP). As expected, photolysis of the pivalate ester resulted in formation of the pyridine-2-thiyl and the t-butyl radical. Photolysis of the Barton ester of 2,2-dimethyl-1,3-dioxolane-4-carboxylic acid, on the other hand, revealed a complex multi-step fragmentation. In addition to the pyridine-2-thiyl and dioxolanyl radical, we gained evidence for the formation of the vinyloxy radical, CH2[double bond, length as m-dash]CHO˙. The latter was identified in the LFP by its π-complexes with benzene and diphenylether, its rapid quenching by electron-rich arenes and tri-n-butyl tin hydride, and its oxidative power in presence of trifluoroacetic acid as demonstrated by the oxidation of ferrocene to ferrocenium. Formation of CH2[double bond, length as m-dash]CHO˙ can be rationalized via fragmentation of the dioxolanyl radical. As the calculated barriers are too high for the reaction sequence to occur on the LFP time scale, we investigated the fragmentation of the photoexcited Barton ester via Born-Oppenheimer molecular dynamics simulations. In one trajectory, we could observe all reaction steps including ring opening of the dioxolanyl radical, suggesting that the excess energy gained in the ester cleavage and decarboxylation may lead to fragmentation of the hot dioxolanyl radical.
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Affiliation(s)
- Götz Bucher
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany
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14
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Hao W, Wu X, Sun JZ, Siu JC, MacMillan SN, Lin S. Radical Redox-Relay Catalysis: Formal [3+2] Cycloaddition of N-Acylaziridines and Alkenes. J Am Chem Soc 2017; 139:12141-12144. [DOI: 10.1021/jacs.7b06723] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Wei Hao
- Department of Chemistry and
Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Xiangyu Wu
- Department of Chemistry and
Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - James Z. Sun
- Department of Chemistry and
Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Juno C. Siu
- Department of Chemistry and
Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Samantha N. MacMillan
- Department of Chemistry and
Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Song Lin
- Department of Chemistry and
Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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15
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Arimitsu S, Oshiro M, Yonamine T. A new umpolung for direct γ-regioselective nucleophilic addition of alcohols to γ-enolizable α,β-unsaturated aldehydes. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2017.05.058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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16
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Burrows ND, Harvey S, Idesis FA, Murphy CJ. Understanding the Seed-Mediated Growth of Gold Nanorods through a Fractional Factorial Design of Experiments. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1891-1907. [PMID: 27983861 DOI: 10.1021/acs.langmuir.6b03606] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Since the development of simple, aqueous protocols for the synthesis of anisotropic metal nanoparticles, research into many promising, valuable applications of gold nanorods has grown considerably, but a number of challenges remain, including gold-particle yield, robustness to minor impurities, and precise control of gold nanorod surface chemistry. Herein we present the results of a composite fractional factorial series of experiments designed to screen seven additional potential avenues of control and to understand the seed-mediated silver-assisted synthesis of gold nanorods. These synthesis variables are the amount of sodium borohydride used and the rate of stirring when producing seed nanoparticles, the age of and the amount of seeds added, the reaction temperature, the amounts of silver nitrate and ascorbic acid added, and the age of the reduced growth solution before seed nanoparticles are added to initiate rod formation. This statistical experimental design and analysis method, besides determining which experimental variables are important and which are not when synthesizing gold nanorods (and quantifying their effects), gives further insight into the mechanism of growth by measuring the degree to which variables interact with each other by mapping out their mechanistic connections. This work demonstrates that when forming gold nanorods by the reduction of auric ions by ascorbic acid onto seed nanoparticles, ascorbic acid determines how much gold is reduced, and the amount of seeds determine how it is divided, yet both influence the intrinsic growth rates, in both width and length, of the forming nanorods. Furthermore, this work shows that the reduction of gold proceeds via direct reduction on the surface of seeds and not through a disproportionation reaction. Further control over the length of gold nanorods can be achieved by tuning the amount of silver nitrate or the reaction temperature. This work shows that silver does not directly influence rod length or width, and a new primary role for silver is proposed as a catalyst promoting the reduction of gold on the ends of forming nanorods. Furthermore, this silver catalyst is removed from the reaction by adsorption onto the surface of the growing nanorod. This work also demonstrates the importance of freshly prepared silver nitrate and ascorbic acid solutions, free from even a few hours of photodegradation, in preparing gold nanorods with high shape purity and gold yield.
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Affiliation(s)
- Nathan D Burrows
- Department of Chemistry, 600 S. Mathews Avenue, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Samantha Harvey
- Department of Chemistry, 600 S. Mathews Avenue, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Fred A Idesis
- Department of Chemistry, 600 S. Mathews Avenue, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Catherine J Murphy
- Department of Chemistry, 600 S. Mathews Avenue, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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17
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Büldt LA, Guo X, Prescimone A, Wenger OS. A Molybdenum(0) Isocyanide Analogue of Ru(2,2′-Bipyridine)32+: A Strong Reductant for Photoredox Catalysis. Angew Chem Int Ed Engl 2016; 55:11247-50. [DOI: 10.1002/anie.201605571] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Laura A. Büldt
- Department of Chemistry; University of Basel; St. Johanns-Ring 19 and Spitalstrasse 51 4056 Basel Switzerland
| | - Xingwei Guo
- Department of Chemistry; University of Basel; St. Johanns-Ring 19 and Spitalstrasse 51 4056 Basel Switzerland
| | - Alessandro Prescimone
- Department of Chemistry; University of Basel; St. Johanns-Ring 19 and Spitalstrasse 51 4056 Basel Switzerland
| | - Oliver S. Wenger
- Department of Chemistry; University of Basel; St. Johanns-Ring 19 and Spitalstrasse 51 4056 Basel Switzerland
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18
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Büldt LA, Guo X, Prescimone A, Wenger OS. Ein Molybdän(0)-Isocyanid-Komplex als Ru(2,2′-Bipyridin)32+-Analogon: ein starkes Reduktionsmittel für die Photoredoxkatalyse. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201605571] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Laura A. Büldt
- Departement Chemie; Universität Basel; St. Johanns-Ring 19 und Spitalstrasse 51 4056 Basel Schweiz
| | - Xingwei Guo
- Departement Chemie; Universität Basel; St. Johanns-Ring 19 und Spitalstrasse 51 4056 Basel Schweiz
| | - Alessandro Prescimone
- Departement Chemie; Universität Basel; St. Johanns-Ring 19 und Spitalstrasse 51 4056 Basel Schweiz
| | - Oliver S. Wenger
- Departement Chemie; Universität Basel; St. Johanns-Ring 19 und Spitalstrasse 51 4056 Basel Schweiz
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Schroll P, König B. Photocatalytic α-Oxyamination of Stable Enolates, Silyl Enol Ethers, and 2-Oxoalkane Phosphonic Esters. European J Org Chem 2014. [DOI: 10.1002/ejoc.201403433] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Zhang N, Samanta SR, Rosen BM, Percec V. Single Electron Transfer in Radical Ion and Radical-Mediated Organic, Materials and Polymer Synthesis. Chem Rev 2014; 114:5848-958. [DOI: 10.1021/cr400689s] [Citation(s) in RCA: 320] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Na Zhang
- Roy & Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Shampa R. Samanta
- Roy & Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Brad M. Rosen
- DuPont Titanium Technologies, Chestnut Run Plaza, Wilmington, Delaware 19805, United States
| | - Virgil Percec
- Roy & Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
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Vu VH, Louafi F, Girard N, Marion R, Roisnel T, Dorcet V, Hurvois JP. Electrochemical Access to 8-(1-Phenyl-ethyl)-1,4-dioxa-8-aza-spiro[4.5]decane-7-carbonitrile. Application to the Asymmetric Syntheses of (+)-Myrtine and Alkaloid (+)-241D. J Org Chem 2014; 79:3358-73. [DOI: 10.1021/jo500104c] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Van Ha Vu
- Sciences Chimiques de Rennes, UMR 6226, CNRS−Université de Rennes 1, 2 Avenue Leon Bernard, 35043 Rennes Cedex, France
| | - Fadila Louafi
- Unité de Recherche CHEMS, Faculté des Sciences
Exactes, Université Constantine1, Route de Ain El Bey, 25000 Constantine, Algérie
| | - Nicolas Girard
- Faculté de Pharmacie, Université de Strasbourg UMR 7200 CNRS/UDS, 74 Route du Rhin, 67401 Illkirch Graffenstaden, France
| | - Ronan Marion
- Sciences Chimiques de Rennes, UMR 6226, CNRS−Université de Rennes 1, Campus de Beaulieu,
Avenue du général Leclerc, 35042 Rennes Cedex, France
| | - Thierry Roisnel
- Sciences Chimiques de Rennes, UMR 6226, CNRS−Université de Rennes 1, Campus de Beaulieu,
Avenue du général Leclerc, 35042 Rennes Cedex, France
| | - Vincent Dorcet
- Sciences Chimiques de Rennes, UMR 6226, CNRS−Université de Rennes 1, Campus de Beaulieu,
Avenue du général Leclerc, 35042 Rennes Cedex, France
| | - Jean-Pierre Hurvois
- Sciences Chimiques de Rennes, UMR 6226, CNRS−Université de Rennes 1, 2 Avenue Leon Bernard, 35043 Rennes Cedex, France
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Riahi A, Muzart J, Abe M, Hoffmann N. On the decarboxylation of 2-methyl-1-tetralone-2-carboxylic acid – oxidation of the enol intermediate by triplet oxygen. NEW J CHEM 2013. [DOI: 10.1039/c3nj00457k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Jacobs AC, Resendiz MJE, Greenberg MM. Product and mechanistic analysis of the reactivity of a C6-pyrimidine radical in RNA. J Am Chem Soc 2011; 133:5152-9. [PMID: 21391681 PMCID: PMC3071645 DOI: 10.1021/ja200317w] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nucleobase radicals are the major reactive intermediates produced when hydroxyl radical reacts with nucleic acids. 5,6-Dihydrouridin-6-yl radical (1) was independently generated from a ketone precursor via Norrish Type I photocleavage in a dinucleotide, single-stranded, and double-stranded RNA. This radical is a model of the major hydroxyl radical adduct of uridine. Tandem lesions resulting from addition of the peroxyl radical derived from 1 to the 5'-adjacent nucleotide are observed by ESI-MS. Radical 1 produces direct strand breaks at the 5'-adjacent nucleotide and at the initial site of generation. The preference for cleavage at these two positions depends upon the secondary structure of the RNA and whether O(2) is present or not. Varying the identity of the 5'-adjacent nucleotide has little effect on strand scission. In general, strand scission is significantly more efficient under anaerobic conditions than when O(2) is present. Strand scission is more than twice as efficient in double-stranded RNA than in a single-stranded oligonucleotide under anaerobic conditions. Internucleotidyl strand scission occurs via β-fragmentation following C2'-hydrogen atom abstraction by 1. The subsequently formed olefin cation radical ultimately yields products containing 3'-phosphate or 3'-deoxy-2'-ketouridine termini. These end groups are proposed to result from competing deprotonation pathways. The dependence of strand scission efficiency from 1 on secondary structure under anaerobic conditions suggests that this reactivity may be useful for extracting additional RNA structural information from hydroxyl radical reactions.
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Affiliation(s)
| | | | - Marc M. Greenberg
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218
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