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Altalhi WAO, Chan B, O'Hair RAJ. Methide Affinity Scale: Key Thermodynamic Data Underpinning Catalysis, Organic Synthesis, and Organometallic and Polymer Chemistry. J Phys Chem A 2024; 128:977-988. [PMID: 38295100 DOI: 10.1021/acs.jpca.3c05974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
Methide transfer reactions play important roles in many areas of chemistry, including the Grignard reaction, in the transmetalation steps of metal-catalyzed cross-coupling reactions, and in the generation of cationic metal polymerization catalysts. Methide affinities (MAs) are the key thermodynamic quantity that underpin such reactions, and yet comprehensive methide affinity scales are poorly developed. Here, B3LYP-D3BJ/def2-TZVP calculations are used to calculate the energy changes (MAs) for cations (MeZ → Z+ + Me-), neutrals (MeY- → Y + Me-), and anions (MeX2- → X- + Me-) derived from permethyl species of all group s and p elements. The MAs range from 2525.8 for the singlet cation F+ to -820.4 kJ/mol for the tetramethylborate anion, Me4B-. The cations show the clearest trends: the MAs in all cases decrease going down the group, while moving across a period, the MAs increase from group 1 to group 2 and then decrease for group 3, remaining about the same or with a modest increase moving to group 4, and then continue to increase across a period to a maximum for the halogens (group 17). The anions and dianions are sensitive to hypervalency; those elements that cannot expand the octet have very unfavorable MAs (e.g., MA of Me4C requires the formation of Me5C- and of Me4B- requires the formation of Me5B2-). To address whether the anion MeY- and dianion MeZ2- are stable, the vertical detachment energies of the anions and dianions were calculated. All of the anions are thermodynamically stable with respect to electron loss, except for Me4N-, while the dianions are all thermodynamically unstable with respect to electron loss. The kinetic stability of the dianions with respect to methide and electron loss was also evaluated for the lowest MAs. The only dianions that might be kinetically stable and observable in the gas phase are Me4Ca2-, Me4Sr2-, and Me4Ba2-. The dianion CF3CaF32- is predicted to be both thermodynamically and kinetically stable in the gas phase.
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Affiliation(s)
- Weam A O Altalhi
- School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
- Department of Chemistry, Prince Sattam Bin Abdulaziz University, Hotat Bani Tamim 16511, Saudi Arabia
| | - Bun Chan
- Graduate School of Engineering, Nagasaki University, Bunkyo 1-14, Nagasaki 852-8521, Japan
- Computational Molecular Science Research Team, RIKEN Center for Computational Science, 7-1-26 minatojima-minami, Cyuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Richard A J O'Hair
- School of Chemistry and Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
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Lin Y, Shi H. Rhodium-Catalyzed Addition of (Trialkylsilyl)arenes to Electrophiles via π-Coordination-Driven C-Si Bond Activation. J Am Chem Soc 2023; 145:22753-22761. [PMID: 37787751 DOI: 10.1021/jacs.3c08603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Aromatic organosilicon compounds serve as valuable synthons due to their diverse reactivities, excellent compatibility with various functional groups, and ready availability. However, (trialkylsilyl)arenes, despite their potential utility, are generally considered unsuitable substrates for transition-metal-catalyzed cross-coupling due to the low polarity of their covalent C(aryl)-Si bonds and the significant steric hindrance imposed by alkyl substituents. These factors render them inert toward reactions with transition metals, such as transmetalation and oxidative addition. In this study, we present a method for the rhodium-catalyzed addition of (trialkylsilyl)arenes to electrophiles via π-coordination-driven desilylation. We propose that a dicationic rhodium species activates the unbiased C(aryl)-Si bond, increasing its polarity by forming an η6-arene complex, thereby facilitating heterolysis. The resulting phenyl anion complex readily engages in addition reactions with external electrophiles, effectively forming C-C bonds. Through comprehensive computational studies, we have unraveled an unexpected stepwise pathway for desilylation with fluoride. This pathway involves the addition of fluoride to the aromatic ring, followed by a 1,2-migration of fluoride, ultimately culminating in the departure of fluorotrimethylsilane.
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Affiliation(s)
- Yunzhi Lin
- Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang Province, China
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, 600 Dunyu Road, Hangzhou 310030, Zhejiang Province, China
| | - Hang Shi
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, 600 Dunyu Road, Hangzhou 310030, Zhejiang Province, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
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Reisinger D, Kriehuber MU, Bender M, Bautista-Anguís D, Rieger B, Schlögl S. Thermally Latent Bases in Dynamic Covalent Polymer Networks and their Emerging Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2300830. [PMID: 36916976 DOI: 10.1002/adma.202300830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/05/2023] [Indexed: 06/16/2023]
Abstract
A novel strategy allowing temporal control of dynamic bond exchange in covalently crosslinked polymer networks via latent transesterification catalysts is introduced. Obtained by a straightforward air- and water-tolerant synthesis, the latent catalyst is designed for an irreversible temperature-mediated release of a strong organic base. Its long-term inactivity at temperatures below 50 °C provides the unique opportunity to equip dynamic covalent networks with creep resistance and high bond-exchange rates, once activated. The presented thermally latent base catalyst is conveniently introducible in readily available building blocks and, as proof of concept, applied in a radically polymerized thiol-ene network. Light-mediated curing is used for 3D-printing functional objects, on which the possibility of spatially controlled reshaping and welding based on dynamic transesterification is illustrated. Since the catalyst is thermally activated, limitations regarding sample geometry and optical transparency do not apply, which facilitates a transfer to well-established industrial technologies. Consequently, fiber-reinforced and highly filled magneto-active thiol-ene polymer composites are fabricated by a thermal curing approach. The on-demand activation of dynamic transesterification is demonstrated by (magneto-assisted) reshaping experiments, highlighting a wide range of potential future applications offered by the presented concept.
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Affiliation(s)
- David Reisinger
- Polymer Competence Center Leoben GmbH, Roseggerstraße 12, Leoben, 8700, Austria
| | | | - Marcel Bender
- Processing of Composites Group, Montanuniversität Leoben, Otto Glöckel-Straße 2, Leoben, 8700, Austria
| | | | - Bernhard Rieger
- WACKER-Chair of Macromolecular Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Sandra Schlögl
- Polymer Competence Center Leoben GmbH, Roseggerstraße 12, Leoben, 8700, Austria
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4
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Yu IF, Manske JL, Diéguez-Vázquez A, Misale A, Pashenko AE, Mykhailiuk PK, Ryabukhin SV, Volochnyuk DM, Hartwig JF. Catalytic undirected borylation of tertiary C-H bonds in bicyclo[1.1.1]pentanes and bicyclo[2.1.1]hexanes. Nat Chem 2023; 15:685-693. [PMID: 36973434 PMCID: PMC10684141 DOI: 10.1038/s41557-023-01159-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 02/14/2023] [Indexed: 03/29/2023]
Abstract
Catalytic borylations of sp3 C-H bonds occur with high selectivities for primary C-H bonds or secondary C-H bonds that are activated by nearby electron-withdrawing substituents. Catalytic borylation at tertiary C-H bonds has not been observed. Here we describe a broadly applicable method for the synthesis of boron-substituted bicyclo[1.1.1]pentanes and (hetero)bicyclo[2.1.1]hexanes by an iridium-catalysed borylation of the bridgehead tertiary C-H bond. This reaction is highly selective for the formation of bridgehead boronic esters and is compatible with a broad range of functional groups (>35 examples). The method is applicable to the late-stage modification of pharmaceuticals containing this substructure and the synthesis of novel bicyclic building blocks. Kinetic and computational studies suggest that C-H bond cleavage occurs with a modest barrier and that the turnover-limiting step of this reaction is an isomerization that occurs prior to reductive elimination that forms the C-B bond.
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Affiliation(s)
- Isaac F Yu
- Department of Chemistry, University of California, Berkeley, CA, USA
| | - Jenna L Manske
- Department of Chemistry, University of California, Berkeley, CA, USA
| | | | | | - Alexander E Pashenko
- The Institute of High Technologies, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
- Enamine Ltd, Kyiv, Ukraine
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Pavel K Mykhailiuk
- The Institute of High Technologies, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
- Enamine Ltd, Kyiv, Ukraine
| | - Sergey V Ryabukhin
- The Institute of High Technologies, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
- Enamine Ltd, Kyiv, Ukraine
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Dmitriy M Volochnyuk
- The Institute of High Technologies, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine.
- Enamine Ltd, Kyiv, Ukraine.
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv, Ukraine.
| | - John F Hartwig
- Department of Chemistry, University of California, Berkeley, CA, USA.
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Perez EH, Schleif T, Messinger JP, Rullán Buxó AG, Moss OC, Greis K, Johnson MA. Structures and Chemical Rearrangements of Benzoate Derivatives Following Gas Phase Decarboxylation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1914-1920. [PMID: 36084146 DOI: 10.1021/jasms.2c00188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Decarboxylation of carboxylate ions in the gas phase provides a useful window into the chemistry displayed by these reactive carbanion intermediates. Here, we explore the species generated by decarboxylation of two benzoate derivatives: 2-formylbenzoate (2FBA) and 2-benzoylbenzoate (2BBA). The nascent product anions are transferred to a cryogenic ion trap where they are cooled to ∼15 K and analyzed by their pattern of vibrational bands obtained with IR photodissociation spectroscopy of weakly bound H2 molecules. The structures of the quenched species are then determined by comparison of these spectra with those predicted by electronic structure calculations for local minima on the potential energy surface. The 2-phenide carbanion generated by decarboxylation of 2FBA occurs in two isomeric forms that differ in the orientation of the formyl group, both of which yield a very large (∼110 cm-1) redshift in the stretching frequency of the H2 molecule attached to the anionic carbon center. Although calculated to be a local minimum, the analogous 2-phenide species could not be isolated upon decarboxylation of 2BBA. Rather, the anionic product adopts a ring-closed structure, indicating efficient nucleophilic attack on the pendant phenyl group by the nascent phenide. The barrier for ring closing is evaluated with electronic structure calculations.
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Affiliation(s)
- Evan H Perez
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Tim Schleif
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Joseph P Messinger
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Anna G Rullán Buxó
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Olivia C Moss
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Kim Greis
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Mark A Johnson
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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Zheng Y, Wu X, Ru C, Zhao H, Han X, Wu J, Pan X. Synthesis, structure and reactivity of a boron-containing spirocycle carbanion. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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Gong X, Çağlayan M, Ye Y, Liu K, Gascon J, Dutta Chowdhury A. First-Generation Organic Reaction Intermediates in Zeolite Chemistry and Catalysis. Chem Rev 2022; 122:14275-14345. [PMID: 35947790 DOI: 10.1021/acs.chemrev.2c00076] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Zeolite chemistry and catalysis are expected to play a decisive role in the next decade(s) to build a more decentralized renewable feedstock-dependent sustainable society owing to the increased scrutiny over carbon emissions. Therefore, the lack of fundamental and mechanistic understanding of these processes is a critical "technical bottleneck" that must be eliminated to maximize economic value and minimize waste. We have identified, considering this objective, that the chemistry related to the first-generation reaction intermediates (i.e., carbocations, radicals, carbenes, ketenes, and carbanions) in zeolite chemistry and catalysis is highly underdeveloped or undervalued compared to other catalysis streams (e.g., homogeneous catalysis). This limitation can often be attributed to the technological restrictions to detect such "short-lived and highly reactive" intermediates at the interface (gas-solid/solid-liquid); however, the recent rise of sophisticated spectroscopic/analytical techniques (including under in situ/operando conditions) and modern data analysis methods collectively compete to unravel the impact of these organic intermediates. This comprehensive review summarizes the state-of-the-art first-generation organic reaction intermediates in zeolite chemistry and catalysis and evaluates their existing challenges and future prospects, to contribute significantly to the "circular carbon economy" initiatives.
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Affiliation(s)
- Xuan Gong
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, Hubei P. R. China
| | - Mustafa Çağlayan
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Yiru Ye
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, Hubei P. R. China
| | - Kun Liu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, Hubei P. R. China
| | - Jorge Gascon
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
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Petroselli M, Bacchiocchi C. Kinetic vs. thermodynamic control of β-functionalized cyclic ketones: a theoretical investigation of regioselective formation of enolates. Org Chem Front 2022. [DOI: 10.1039/d2qo01343f] [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 reported theoretical study sheds light on the regioselective formation of enolates in β-functionalized ketones, highlighting the importance of non-covalent interactions.
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Affiliation(s)
- Manuel Petroselli
- Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, CH 8093 Zürich, Switzerland
| | - Corrado Bacchiocchi
- School of Science and Technology, Chemistry Division, University of Camerino, Via S. Agostino 1, 62032 Camerino (MC), Italy
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Abstract
We have applied a combination of tandem-mass spectrometry, quantum-chemical calculations, and statistical rate theory computations to examine the gas phase reactions between the trisarylzincate anions ArXZnPh2- (ArX = p-X-C6H4, X = NMe2, OMe, Me, H, F, and Cl) and 2,2,2-trifluoroethanol at T = 310 ± 20 K. The observed reactions bring about the protonation of one of the aryl anions, which is then released as the corresponding arene, while the formed alkoxide binds to the zinc center. The protonation is faster for the more electron-rich aryl groups and shows a linear Hammett plot if the rate constant for X = NMe2 is discarded from the analysis. Although the reactions are highly exothermic, they proceed only with relatively low efficiencies (0.1% ≤ φ ≤ 1.3%). According to the quantum-chemical calculations, this behavior can be ascribed to the reactions proceeding through a double-well potential with a tight transition structure located at the central barrier. Based on these potential energy surfaces, the statistical rate theory computations can reproduce the measured rate constants within factors of 2 to 8. A comparison of the protolysis of the trisarylzincates with that of the corresponding free aryl anions demonstrates how the coordination to the metal center not only stabilizes the carbanions energetically but also moderates their reactivity. Thus, our gas phase study contributes to a better understanding of the fundamentals of organometallic reactivity.
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Affiliation(s)
- Rene Rahrt
- Institut für Organische und Biomolekulare Chemie, Universität Göttingen, Tammannstr. 2, Göttingen 37077, Germany
| | - Konrad Koszinowski
- Institut für Organische und Biomolekulare Chemie, Universität Göttingen, Tammannstr. 2, Göttingen 37077, Germany
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Conder CJ, Jawale H, Wenthold PG. Mass spectrometry studies of nitrene anions. MASS SPECTROMETRY REVIEWS 2021:e21751. [PMID: 34842299 DOI: 10.1002/mas.21751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
Nitrene anions are a class of reactive intermediates that provide a means for studying the corresponding neutral molecules via electron photodetachment spectroscopy and photoelectron spectroscopy. The added electron makes it possible for protected nitrene anions to be manipulated by external electric and magnetic fields of a mass spectrometer. Nitrene anions also display their own unique reactivities as reagents, which have been investigated using ion/molecule reactions. Mass spectrometry of negative ions has thereby provided information on the electronic states, reactivities, and thermochemical properties of nitrene intermediates. This review also includes a discussion of condensed-phase nitrene anions.
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Affiliation(s)
- Cory J Conder
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Harshal Jawale
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Paul G Wenthold
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
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11
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Huo Z, Wang Y, Feng X, He Y, Qiu F. Tracking the deprotonation site of dehydroandrographolide with electrospray ionization mass spectrometry by deuteration. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35:e9152. [PMID: 34181280 DOI: 10.1002/rcm.9152] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/14/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
RATIONALE Dehydroandrographolide (DA) is a diterpene compound of biological interest that contains one α,β-unsaturated lactone group and two hydroxy groups. In the ESI (electrospray ionization) negative ion mode mass spectral analysis of 15-dideuterodehydroandrographolide (15-D2 -DA), the deuterium nucleus at the γ position of the α,β-unsaturated lactone was more easily dedeuterated than deprotonation of the protons from the hydroxy groups. Exploring the rationality of deuteration as a tool for deprotonation position tracking is significant for gas-phase acidity. METHODS The mass spectra of DA and 15-D2 -DA in positive and negative ion mode were acquired by liquid chromatography/ion trap time-of-flight mass spectrometry (LC/IT-TOF) systems. The deprotonation and dedeuteration energies at specific sites were calculated by the B3LYP and M06-2X density functional theory (DFT) methods with the program Gaussian 16. RESULTS The [M + H]+ ion of 15-D2 -DA was 2 amu larger than that of DA due to the substitution of two hydrogens with two deuteriums; however, the anion base peak of 15-D2 -DA was only 1 amu larger than that of the [M - H]- ion of DA. Dedeuteration at the C15 site was proposed according to the mass spectral data. The deprotonation (dedeuteration) energies calculated by the B3LYP/6-311++G(3df,3pd)//B3LYP/6-31 + G(d) and M06-2X-D3/ma-TZVP methods showed that the C-H and C-D bonds at the C15 site have lower deprotonation (dedeuteration) energies than the energies of the hydroxy groups of DA, making their deprotonation (dedeuteration) more thermodynamically favourable. CONCLUSIONS Deuteration of DA provided direct evidence of the deprotonation site of DA in the ESI source of the mass spectrometer, and the DFT method well predicted the gas-phase deprotonation site of DA.
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Affiliation(s)
- Zhipeng Huo
- School of Chinese Materia Medica, and State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
- TCM Research Center, Tasly Academy, Tasly Holding Group Co. Ltd, Tianjin, China
- State Key Laboratory of Critical Technology in Innovative Chinese Medicine, Tasly Pharmaceutical Co. Ltd, Tianjin, China
| | - Yu Wang
- TCM Research Center, Tasly Academy, Tasly Holding Group Co. Ltd, Tianjin, China
- State Key Laboratory of Critical Technology in Innovative Chinese Medicine, Tasly Pharmaceutical Co. Ltd, Tianjin, China
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Tianjin, China
| | - Xinchi Feng
- School of Chinese Materia Medica, and State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yi He
- TCM Research Center, Tasly Academy, Tasly Holding Group Co. Ltd, Tianjin, China
- State Key Laboratory of Critical Technology in Innovative Chinese Medicine, Tasly Pharmaceutical Co. Ltd, Tianjin, China
| | - Feng Qiu
- School of Chinese Materia Medica, and State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
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12
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Eisele NF, Koszinowski K. Direct Detection of Free and Counterion-Bound Carbanions by Electrospray-Ionization Mass Spectrometry. J Org Chem 2021; 86:3750-3757. [PMID: 33599503 DOI: 10.1021/acs.joc.0c02504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We propose electrospray-ionization (ESI) mass spectrometry as a robust and powerful method for the in situ analysis of carbanions. ESI mass spectrometry selectively probes the charged components of the sampled solution and, thus, is ideally suited for the detection of free carbanions. We demonstrate the potential of this method by analyzing acetonitrile solutions of 15 different carbon acids AH, whose acidities cover a range of 11.1 ≤ pKa(DMSO) ≤ 29.5. After treatment with KOtBu as a strong base, all but the two least acidic compounds were successfully detected as free carbanions A- and/or as potassium-bound aggregates [Kn-1An]-. The association equilibria can be shifted toward smaller aggregates and free carbanions by the addition of the crown ether 18-crown-6, which facilitates the evaluation of the mass spectra. When KOtBu was replaced by other bases (LiOH, LiNiPr2, NaH, NaOH, KOH, NBu4OH) or when tetrahydrofuran or methanol was used as a solvent, carbanions were also successfully observed. For further demonstrating the utility of the proposed method, we applied it to the analysis of the Michael addition of deprotonated dimedone to butenone. ESI mass spectrometry allowed us to follow the decrease of the reactant carbanion and the buildup of the product carbanion in time.
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Affiliation(s)
- Niklas F Eisele
- Institut für Organische und Biomolekulare Chemie, Universität Göttingen, Tammannstraße 2, 37077 Göttingen, Germany
| | - Konrad Koszinowski
- Institut für Organische und Biomolekulare Chemie, Universität Göttingen, Tammannstraße 2, 37077 Göttingen, Germany
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Dias HJ, Crevelin EJ, Palaretti V, Vessecchi R, Crotti AEM. Electrospray ionization tandem mass spectrometry of deprotonated dihydrobenzofuran neolignans. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35:e8990. [PMID: 33119941 DOI: 10.1002/rcm.8990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/21/2020] [Accepted: 10/24/2020] [Indexed: 06/11/2023]
Abstract
RATIONALE Although dihydrobenzofuran neolignans (DBNs) display a wide diversity of biological activities, the identification of their in vivo metabolites using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) remains a challenge to be overcome. Recently, ESI-MS/MS data of protonated DBNs have been reported, but they were shown to be limited due to the scarcity of diagnostic ions. METHODS The gas-phase fragmentation pathways of a series of biologically active synthetic benzofuran neolignans (BNs) and DBNs were elucidated by means of negative ESI accurate-mass tandem and sequential mass spectrometry, and thermochemical data estimated using computational chemistry and the B3LYP/6-31+G(d,p) model. RESULTS Deprotonated DBNs produced more diagnostic product ions than the corresponding protonated molecules. Moreover, a series of odd-electron product ions (radical anions) were detected, which has not been reported for protonated DBNs. Direct C2 H3 O2 • elimination from the precursor ion (deprotonated molecule) only occurred for the BNs and can help to distinguish these compounds from the DBNs. The mechanism through which the [M - H - CH3 OH]- ion is formed is strongly dependent on specific structural features. CONCLUSIONS The negative ion mode provides much more information than the positive ion mode (at least one diagnostic product ion was detected for all the analyzed compounds) and does not require the use of additives to produce the precursor ions (deprotonated molecules).
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Affiliation(s)
- Herbert J Dias
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Eduardo J Crevelin
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Vinicius Palaretti
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Ricardo Vessecchi
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Antônio E M Crotti
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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14
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Valadbeigi Y. Acidity enhancement of sulfonic acid derivatives by hydrogen bond networks. COMPUT THEOR CHEM 2021. [DOI: 10.1016/j.comptc.2020.113054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Anstöter CS, Verlet JRR. Gas-Phase Synthesis and Characterization of the Methyl-2,2-dicyanoacetate Anion Using Photoelectron Imaging and Dipole-Bound State Autodetachment. J Phys Chem Lett 2020; 11:6456-6462. [PMID: 32687376 DOI: 10.1021/acs.jpclett.0c02036] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The methyl-2,2-dicyanoacetate anion is synthesized in an electrospray ionization source through a gas-phase reaction involving tetracyanoethylene and methanol. Photoelectron imaging is used to determine the isomeric form of the product. The photoelectron spectra and angular distributions are consistent with only a single isomer. Additionally, mode-specific vibrational autodetachment is observed. This can be correlated with the emission from a photoexcited dipole-bound state by considering the IR spectrum of the neutral molecule, adding further confirmation of the isomeric form and providing a binding energy of the dipole-bound state. Our experiments show how conventional photoelectron imaging can be used to determine detailed information about gas-phase reaction products.
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Affiliation(s)
- Cate S Anstöter
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
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16
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van Stipdonk MJ, Tatosian IJ, Iacovino AC, Bubas AR, Metzler LJ, Sherman MC, Somogyi A. Gas-Phase Deconstruction of UO 22+: Mass Spectrometry Evidence for Generation of [OU VICH] + by Collision-Induced Dissociation of [U VIO 2(C≡CH)] . JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:796-805. [PMID: 30911904 DOI: 10.1007/s13361-019-02179-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/04/2019] [Accepted: 03/05/2019] [Indexed: 06/09/2023]
Abstract
Because of the high stability and inertness of the U=O bonds, activation and/or functionalization of UO22+ and UO2+ remain challenging tasks. We show here that collision-induced dissociation (CID) of the uranyl-propiolate cation, [UVIO2(O2C-C≡CH)]+, can be used to prepare [UVIO2(C≡CH)]+ in the gas phase by decarboxylation. Remarkably, CID of [UVIO2(C≡CH)]+ caused elimination of CO to create [OUVICH]+, thus providing a new example of a well-defined substitution of an "yl" oxo ligand of UVIO22+ in a unimolecular reaction. Relative energies for candidate structures based on density functional theory calculations suggest that the [OUVICH]+ ion is a uranium-methylidyne product, with a U≡C triple bond composed of one σ-bond with contributions from the U df and C sp hybrid orbitals, and two π-bonds with contributions from the U df and C p orbitals. Upon isolation, without imposed collisional activation, [OUVICH]+ appears to react spontaneously with O2 to produce [UVO2]+. Graphical Abstract .
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Affiliation(s)
- Michael J van Stipdonk
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA.
| | - Irena J Tatosian
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA
| | - Anna C Iacovino
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA
| | - Amanda R Bubas
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA
- Department of Chemistry, University of Utah, 315 1400 E, Salt Lake City, UT, 84112, USA
| | - Luke J Metzler
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA
| | - Mary C Sherman
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA
| | - Arpad Somogyi
- Mass Spectrometry and Proteomics Facility, Campus Chemical Instrument Center, The Ohio State University, Columbus, OH, 43210, USA
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17
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Locke GM, Bernhard SSR, Senge MO. Nonconjugated Hydrocarbons as Rigid-Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry. Chemistry 2019; 25:4590-4647. [PMID: 30387906 DOI: 10.1002/chem.201804225] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 10/20/2018] [Indexed: 01/02/2023]
Abstract
Nonconjugated hydrocarbons, like bicyclo[1.1.1]pentane, bicyclo[2.2.2]octane, triptycene, and cubane are a unique class of rigid linkers. Due to their similarity in size and shape they are useful mimics of classic benzene moieties in drugs, so-called bioisosteres. Moreover, they also fulfill an important role in material sciences as linear linkers, in order to arrange various functionalities in a defined spatial manner. In this Review article, recent developments and usages of these special, rectilinear systems are discussed. Furthermore, we focus on covalently linked, nonconjugated linear arrangements and discuss the physical and chemical properties and differences of individual linkers, as well as their application in material and medicinal sciences.
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Affiliation(s)
- Gemma M Locke
- School of Chemistry, SFI Tetrapyrrole Laboratory, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse Street, Dublin, 2, Ireland
| | - Stefan S R Bernhard
- School of Chemistry, SFI Tetrapyrrole Laboratory, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse Street, Dublin, 2, Ireland
| | - Mathias O Senge
- School of Chemistry, SFI Tetrapyrrole Laboratory, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse Street, Dublin, 2, Ireland
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18
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Wang Y, Cai PJ, Yu ZX. Carbanion Translocations via Intramolecular Proton Transfers: A Quantum Chemical Study. J Org Chem 2017; 82:4604-4612. [DOI: 10.1021/acs.joc.7b00194] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Yi Wang
- Beijing National Laboratory
for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry
and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Pei-Jun Cai
- Beijing National Laboratory
for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry
and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Zhi-Xiang Yu
- Beijing National Laboratory
for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry
and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
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19
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Stanley LH, Anstöter CS, Verlet JRR. Resonances of the anthracenyl anion probed by frequency-resolved photoelectron imaging of collision-induced dissociated anthracene carboxylic acid. Chem Sci 2017; 8:3054-3061. [PMID: 28451374 PMCID: PMC5380881 DOI: 10.1039/c6sc05405f] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/01/2017] [Indexed: 01/04/2023] Open
Abstract
The use of CID and photoelectron spectroscopy of organic carboxylic acid anions is discussed as a route to studying the dynamics of resonances in polyaromatic hydrocarbon (PAH) anions.
Resonances in polyaromatic hydrocarbon (PAH) anions are key intermediates in a number of processes such as electron transfer in organic electronics and electron attachment in the interstellar medium. Here we present a frequency- and angle-resolved photoelectron imaging study of the 9-anthracenyl anion generated through collision induced dissociation (CID) of its electrosprayed deprotonated anthracene carboxylic acid anion. We show that a number of π* resonances are active in the first 2.5 eV above the threshold. The photoelectron spectra and angular distributions revealed that nuclear dynamics compete with autodetachment for one of the resonances, while higher-lying resonances were dominated by prompt autodetachment. Based on electronic structure calculations, these observations were accounted for on the basis of the expected autodetachment rates of the resonances. Virtually no ground state recovery was observed, suggesting that the smallest deprotonated PAH that leads to ground state recovery is the tetracenyl anion, for which clear thermionic emission has been observed. The use of CID and photodissociation of organic carboxylic acid anions is discussed as a route to studying the dynamics of resonances in larger PAH anions.
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Affiliation(s)
| | - Cate S Anstöter
- Department of Chemistry , Durham University , Durham DH1 3LE , UK .
| | - Jan R R Verlet
- Department of Chemistry , Durham University , Durham DH1 3LE , UK .
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20
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Poad BLJ, Reed ND, Hansen CS, Trevitt AJ, Blanksby SJ, Mackay EG, Sherburn MS, Chan B, Radom L. Preparation of an ion with the highest calculated proton affinity: ortho-diethynylbenzene dianion. Chem Sci 2016; 7:6245-6250. [PMID: 30034765 PMCID: PMC6024202 DOI: 10.1039/c6sc01726f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/17/2016] [Indexed: 11/23/2022] Open
Abstract
Owing to the increased proton affinity that results from additional negative charges, multiply-charged anions are shown as a route to preparing powerful ‘superbases’.
Owing to the increased proton affinity that results from additional negative charges, multiply-charged anions have been proposed as one route to prepare and access a range of new and powerful “superbases”. Paradoxically, while the additional electrons in polyanions increase basicity they serve to diminish the electron binding energy and thus, it had been thought, hinder experimental synthesis. We report the synthesis and isolation of the ortho-diethynylbenzene dianion (ortho-DEB2–) and present observations of this novel species undergoing gas-phase proton-abstraction reactions. Using a theoretical model based on Marcus–Hush theory, we attribute the stability of ortho-DEB2– to the presence of a barrier that prevents spontaneous electron detachment. The proton affinity of 1843 kJ mol–1 calculated for this dianion superbase using high-level quantum chemistry calculations significantly exceeds that of the lithium monoxide anion, the most basic system previously prepared. The ortho-diethynylbenzene dianion is therefore the strongest base that has been experimentally observed to date.
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Affiliation(s)
- Berwyck L J Poad
- Central Analytical Research Facility , Institute for Future Environments , Queensland University of Technology , Brisbane , QLD 4001 , Australia . .,School of Chemistry , University of Wollongong , Gwynneville , NSW 2522 , Australia
| | - Nicholas D Reed
- School of Chemistry , University of Wollongong , Gwynneville , NSW 2522 , Australia
| | - Christopher S Hansen
- School of Chemistry , University of Wollongong , Gwynneville , NSW 2522 , Australia
| | - Adam J Trevitt
- School of Chemistry , University of Wollongong , Gwynneville , NSW 2522 , Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility , Institute for Future Environments , Queensland University of Technology , Brisbane , QLD 4001 , Australia .
| | - Emily G Mackay
- Research School of Chemistry , Australian National University , Canberra , ACT 2601 , Australia
| | - Michael S Sherburn
- Research School of Chemistry , Australian National University , Canberra , ACT 2601 , Australia
| | - Bun Chan
- School of Chemistry , University of Sydney , Sydney , NSW 2006 , Australia
| | - Leo Radom
- School of Chemistry , University of Sydney , Sydney , NSW 2006 , Australia
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21
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Navrátil R, Tarábek J, Linhart I, Martinů T. Radical and Nitrenoid Reactivity of 3-Halo-3-phenyldiazirines. Org Lett 2016; 18:3734-7. [PMID: 27437559 DOI: 10.1021/acs.orglett.6b01753] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
3-Halo-3-phenyl-3H-diazirines (halogen = Br or Cl) undergo a dissociative single-electron transfer from alkyllithiums (RLi) in THF-based solvent mixtures. The resulting 3-phenyldiazirinyl radical, observed by EPR spectroscopy, is eventually transformed to benzonitrile. In Et2O, 2 equiv of RLi add to both nitrogens of halodiazirine N═N bond, affording N,N'-dialkylbenzamidines. The nitrenoid reactivity of some N-alkyl-1H-diazirine intermediates is manifested by their insertion into the α-C-H bond of THF or Et2O.
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Affiliation(s)
- Rafael Navrátil
- Department of Organic Chemistry, University of Chemistry and Technology , Technická 5, 166 28 Prague, Czech Republic
| | - Ján Tarábek
- Institute of Organic Chemistry and Biochemistry CAS, v.v.i., Flemingovo náměstí 542/2, 166 10 Prague, Czech Republic
| | - Igor Linhart
- Department of Organic Chemistry, University of Chemistry and Technology , Technická 5, 166 28 Prague, Czech Republic
| | - Tomáš Martinů
- Department of Organic Chemistry, University of Chemistry and Technology , Technická 5, 166 28 Prague, Czech Republic
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22
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Archambeau A, Nguyen DV, Meyer C, Cossy J. Rhodium(II)-Catalyzed Isomerization of Cyclopropenylmethyl Esters into (Acyloxymethylene)cyclopropanes. Chemistry 2016; 22:6100-10. [DOI: 10.1002/chem.201505063] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Alexis Archambeau
- Laboratoire de Chimie Organique; Institute of Chemistry, Biology, and Innovation (CBI); ESPCI Paris, CNRS (UMR 8231); PSL Research University; 10 rue Vauquelin 75231 Paris Cedex 05 France
| | - Dinh-Vu Nguyen
- Laboratoire de Chimie Organique; Institute of Chemistry, Biology, and Innovation (CBI); ESPCI Paris, CNRS (UMR 8231); PSL Research University; 10 rue Vauquelin 75231 Paris Cedex 05 France
| | - Christophe Meyer
- Laboratoire de Chimie Organique; Institute of Chemistry, Biology, and Innovation (CBI); ESPCI Paris, CNRS (UMR 8231); PSL Research University; 10 rue Vauquelin 75231 Paris Cedex 05 France
| | - Janine Cossy
- Laboratoire de Chimie Organique; Institute of Chemistry, Biology, and Innovation (CBI); ESPCI Paris, CNRS (UMR 8231); PSL Research University; 10 rue Vauquelin 75231 Paris Cedex 05 France
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23
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Danikiewicz W, Zimnicka M. Negative ion gas-phase chemistry of arenes. MASS SPECTROMETRY REVIEWS 2016; 35:123-146. [PMID: 25851641 DOI: 10.1002/mas.21467] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 01/19/2015] [Indexed: 06/04/2023]
Abstract
Reactions of aromatic and heteroaromatic compounds involving anions are of great importance in organic synthesis. Some of these reactions have been studied in the gas phase and are occasionally mentioned in reviews devoted to gas-phase negative ion chemistry, but no reviews exist that collect all existing information about these reactions. This work is intended to fill this gap. In the first part of this review, methods for generating arene anions in the gas phase and studying their physicochemical properties and fragmentation reactions are presented. The main topics in this part are as follows: processes in which gas-phase arene anions are formed, measurements and calculations of the proton affinities of arene anions, proton exchange reactions, and fragmentation processes of substituted arene anions, especially phenide ions. The second part is devoted to gas-phase reactions of arene anions. The most important of these are reactions with electrophiles such as carbonyl compounds and α,β-unsaturated carbonyl and related compounds (Michael acceptors). Other reactions including oxidation of arene anions and halogenophilic reactions are also presented. In the last part of the review, reactions of electrophilic arenes with nucleophiles are discussed. The best known of these is the aromatic nucleophilic substitution (SN Ar) reaction; however, other processes that lead to the substitution of a hydrogen atom in the aromatic ring are also very important. Aromatic substrates in these reactions are usually but not always nitroarenes bearing other substituents in the ring. The first step in these reactions is the formation of an anionic σ-adduct, which, depending on the substituents in the aromatic ring and the structure of the attacking nucleophile, is either an intermediate or a transition state in the reaction path. In the present review, we attempted to collect the results of both experimental and computational studies of the aforementioned reactions conducted since the very beginning of gas-phase negative ion chemistry.
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Affiliation(s)
- Witold Danikiewicz
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Magdalena Zimnicka
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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24
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Grossert JS, Pippione AC, Boschi D, Lolli ML, White RL. Heterocyclic ring cleavage upon collision-induced dissociation of deprotonated 3-hydroxy-1,2,5-oxadiazoles (3-hydroxyfurazans). JOURNAL OF MASS SPECTROMETRY : JMS 2015; 50:1433-1437. [PMID: 26634978 DOI: 10.1002/jms.3724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/02/2015] [Accepted: 10/20/2015] [Indexed: 06/05/2023]
Abstract
A series of 4-substituted 3-hydroxyfurazans were subjected to electrospray ionization tandem mass spectrometry. At low collision energy, oxyisocyanate ([O=C=N-O](-), m/z 58) was formed as the predominant product ion from each deprotonated 3-hydroxyfurazan, indicating cleavage of the heterocyclic ring. The facile energetics of this characteristic fragmentation process was confirmed by density functional computations.
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Affiliation(s)
- J Stuart Grossert
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, PO Box 15000, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Agnese C Pippione
- Dipartimento di Scienza e Tecnologia del Farmaco (DSTF), Università degli Studi di Torino, via Pietro Giuria 9, 10125, Torino, Italy
| | - Donatella Boschi
- Dipartimento di Scienza e Tecnologia del Farmaco (DSTF), Università degli Studi di Torino, via Pietro Giuria 9, 10125, Torino, Italy
| | - Marco L Lolli
- Dipartimento di Scienza e Tecnologia del Farmaco (DSTF), Università degli Studi di Torino, via Pietro Giuria 9, 10125, Torino, Italy
| | - Robert L White
- Department of Chemistry, Dalhousie University, 6274 Coburg Road, PO Box 15000, Halifax, Nova Scotia, B3H 4R2, Canada
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25
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Shen S, Chai Y, Liu Y, Li C, Pan Y. Benzyl anion transfer in the fragmentation of N-(phenylsulfonyl)-benzeneacetamides: a gas-phase intramolecular S(N)Ar reaction. Org Biomol Chem 2015; 13:10205-11. [PMID: 26309220 DOI: 10.1039/c5ob01582k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In this study, we report a gas-phase benzyl anion transfer via intramolecular aromatic nucleophilic substitution (SNAr) during the course of tandem mass spectrometry of deprotonated N-(phenylsulfonyl)-benzeneacetamide. Upon collisional activation, the formation of the initial ion/neutral complex ([C6H5CH2(-)/C6H5SO2NCO]), which was generated by heterolytic cleavage of the CH2-CO bond, is proposed as the key step. Subsequently, the anionic counterpart, benzyl anion, is transferred to conduct the intra-complex SNAr reaction. After losing neutral HNCO, the intermediate gives rise to product ion B at m/z 231, whose structure is confirmed by comparing the multistage spectra with those of deprotonated 2-benzylbenzenesulfinic acid and (benzylsulfonyl)benzene. In addition, intra-complex proton transfer is also observed within the complex [C6H5CH2(-)/C6H5SO2NCO] to generate product ion C at m/z 182. The INC-mediated mechanism was corroborated by theoretical calculations, isotope experiments, breakdown curve, substituent experiments, etc. This work may provide further understanding of the physicochemical properties of the gaseous benzyl anion.
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Affiliation(s)
- Shanshan Shen
- Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
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26
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Oliveira AM, Lu YJ, Lehman JH, Changala PB, Baraban JH, Stanton JF, Lineberger WC. Photoelectron Spectroscopy of the Methide Anion: Electron Affinities of •CH3 and •CD3 and Inversion Splittings of CH3– and CD3–. J Am Chem Soc 2015; 137:12939-45. [PMID: 26389796 DOI: 10.1021/jacs.5b07013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | - Joshua H. Baraban
- Department
of Chemistry, University of Texas, Austin, Texas 78712, United States
| | - John F. Stanton
- Department
of Chemistry, University of Texas, Austin, Texas 78712, United States
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27
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Lesage D, Barozzino-Consiglio G, Duwald R, Fressigné C, Harrison-Marchand A, Faull KF, Maddaluno J, Gimbert Y. A Lithium Amide Protected Against Protonation in the Gas Phase: Unexpected Effect of LiCl. J Org Chem 2015; 80:6441-6. [DOI: 10.1021/acs.joc.5b00875] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Denis Lesage
- Sorbonne
Universités, UPMC UNIV Paris 06, Institut Parisien de Chimie Moléculaire, UMR CNRS 8232, Case 45, 4 Place Jussieu, 75252 Paris Cedex 05, France
| | | | - Romain Duwald
- Normandie
Université (COBRA), UMR CNRS-Université de Rouen-INSA de Rouen 6014, 76821 Mont St Aignan Cedex, France
| | - Catherine Fressigné
- Normandie
Université (COBRA), UMR CNRS-Université de Rouen-INSA de Rouen 6014, 76821 Mont St Aignan Cedex, France
| | - Anne Harrison-Marchand
- Normandie
Université (COBRA), UMR CNRS-Université de Rouen-INSA de Rouen 6014, 76821 Mont St Aignan Cedex, France
| | - Kym F. Faull
- Pasarow
Mass Spectrometry Laboratory, Semel Institute for Neuroscience and
Human Behavior and Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, California, 90019 United States
| | - Jacques Maddaluno
- Normandie
Université (COBRA), UMR CNRS-Université de Rouen-INSA de Rouen 6014, 76821 Mont St Aignan Cedex, France
| | - Yves Gimbert
- Université
Grenoble Alpes (DCM), UMR CNRS-UJF 5250 BP 53, 38041 Grenoble Cedex 9, France
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28
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Crestoni ME, Chiavarino B, Fornarini S. Nitrosyl–heme and anion–arene complexes: structure, reactivity and spectroscopy. PURE APPL CHEM 2015. [DOI: 10.1515/pac-2014-1203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
AbstractTwo topics are selected and illustrated to exemplify (i) a biological and (ii) an organic ionic intermediate. The reactivity behavior of NO adducts with ferric and ferrous hemes has shown remarkable similarities when examined in the gas phase, demonstrating that the largely different NO affinity displayed in solution and in biological media is due to the different coordination environment. In fact, ferrous hemes present a vacant or highly labile axial coordination site, prone to readily bind NO. The vibrational signatures of the NO ligand have also been probed in vacuo for the first time in the nitrosyl complexes deriving from ferrous and ferric hemes under strictly comparable five-coordination at the metal center. Negatively charged σ-adducts, from the association of anions with 1,3,5-trinitrobenzene, an exemplary π-electron-deficient arene, have been probed by IRMPD spectroscopy and found to display variable binding motifs from a strongly covalent σ-adduct (Meisenheimer complex) to a weakly covalent σ-complex, depending on the anion basicity.
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Affiliation(s)
- Maria Elisa Crestoni
- 1Dipartimento di Chimica e Tecnologie del Farmaco, Università degli Studi di Roma La Sapienza, P.le A. Moro 5, I-00185, Roma, Italy
| | - Barbara Chiavarino
- 1Dipartimento di Chimica e Tecnologie del Farmaco, Università degli Studi di Roma La Sapienza, P.le A. Moro 5, I-00185, Roma, Italy
| | - Simonetta Fornarini
- 1Dipartimento di Chimica e Tecnologie del Farmaco, Università degli Studi di Roma La Sapienza, P.le A. Moro 5, I-00185, Roma, Italy
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29
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O’Hair RAJ, Rijs NJ. Gas phase studies of the Pesci decarboxylation reaction: synthesis, structure, and unimolecular and bimolecular reactivity of organometallic ions. Acc Chem Res 2015; 48:329-40. [PMID: 25594228 DOI: 10.1021/ar500377u] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
CONSPECTUS: Decarboxylation chemistry has a rich history, and in more recent times, it has been recruited in the quest to develop cheaper, cleaner, and more efficient bond-coupling reactions. Thus, over the past two decades, there has been intense investigation into new metal-catalyzed reactions of carboxylic substrates. Understanding the elementary steps of metal-mediated transformations is at the heart of inventing new reactions and improving the performance of existing ones. Fortunately, during the same time period, there has been a convergence in mass spectrometry (MS) techniques, which allows these catalytic processes to be examined efficiently in the gas phase. Thus, electrospray ionization (ESI) sources have been combined with ion-trap mass spectrometers, which in turn have been modified to either accept radiation from tunable OPO lasers for spectroscopy based structural assignment of ions or to allow the study of ion-molecule reactions (IMR). The resultant "complete" gas-phase chemical laboratories provide a platform to study the elementary steps of metal-catalyzed decarboxylation reactions in exquisite detail. In this Account, we illustrate how the powerful combination of ion trap mass spectrometry experiments and DFT calculations can be systematically used to examine the formation of organometallic ions and their chemical transformations. Specifically, ESI-MS allows the transfer of inorganic carboxylate complexes, [RCO2M(L)n](x), (x = charge) from the condensed to the gas phase. These mass selected ions serve as precursors to organometallic ions [RM(L)n](x) via neutral extrusion of CO2, accessible by slow heating in the ion trap using collision induced dissociation (CID). This approach provides access to an array of organometallic ions with well-defined stoichiometry. In terms of understanding the decarboxylation process, we highlight the role of the metal center (M), the organic group (R), and the auxiliary ligand (L), along with cluster nuclearity, in promoting the formation of the organometallic ion. Where isomeric organometallic ions are generated and normal MS approaches cannot distinguish them, we describe approaches to elucidate the decarboxylation mechanism via determination of their structure. These "unmasked" organometallic ions, [RM(L)n](x), can also be structurally interrogated spectroscopically or via CID. We have thus compared the gas-phase structures and decomposition of several highly reactive and synthetically important organometallic ions for the first time. Perhaps the most significant aspect of this work is the study of bimolecular reactions, which provides experimental information on mechanistically obscure bond-formation and cross-coupling steps and the intrinsic reactivity of ions. We have sought to understand transformations of substrates including acid-base and hydrolysis reactions, along with reactions resulting in C-C bond formation. Our studies also allow a direct comparison of the performance of different metal catalysts in the individual elementary steps associated with protodecarboxylation and decarboxylative alkylation cycles. Electronic structure (DFT and ab initio) and dynamics (RRKM) calculations provide further mechanistic insights into these reactions. The broad implications of this research are that new reactions can be discovered and that the performance of metal catalysts can be evaluated in terms of each of their elementary steps. This has been particularly useful for the study of metal-mediated decarboxylation reactions.
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Affiliation(s)
- Richard A. J. O’Hair
- School of Chemistry, University of Melbourne, Melbourne, Victoria 3010, Australia
- Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
- ARC Centre of Excellence in Free Radical Chemistry and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Nicole J. Rijs
- School of Chemistry, University of Melbourne, Melbourne, Victoria 3010, Australia
- Bio21 Institute of Molecular Science and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
- ARC Centre of Excellence in Free Radical Chemistry and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 115, 10623 Berlin, Germany
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Li J, Khairallah GN, O’Hair RAJ. Dimethylcuprate-Mediated Transformation of Acetate to Dithioacetate. Organometallics 2015. [DOI: 10.1021/om501117p] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Jiawei Li
- School
of Chemistry, Bio21
Institute of Molecular Science and Biotechnology, and ARC Centre of Excellence for Free Radical Chemistry
and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - George N. Khairallah
- School
of Chemistry, Bio21
Institute of Molecular Science and Biotechnology, and ARC Centre of Excellence for Free Radical Chemistry
and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Richard A. J. O’Hair
- School
of Chemistry, Bio21
Institute of Molecular Science and Biotechnology, and ARC Centre of Excellence for Free Radical Chemistry
and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
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Perrin CL, Reyes-Rodríguez GJ. Selectivity and Isotope Effects in Hydronation of a Naked Aryl Anion. J Am Chem Soc 2014; 136:15263-9. [DOI: 10.1021/ja507517g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Charles L. Perrin
- Department of Chemistry & Biochemistry, University of California-San Diego, La Jolla, California 92093-0358, United States
| | - Gabriel J. Reyes-Rodríguez
- Department of Chemistry & Biochemistry, University of California-San Diego, La Jolla, California 92093-0358, United States
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Hanzlová E, Váňa J, Shaffer CJ, Roithová J, Martinů T. Evidence for the cyclic CN2 carbene in the gas phase. Org Lett 2014; 16:5482-5. [PMID: 25296289 DOI: 10.1021/ol5027602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
3-Halodiazirine-3-carboxylic acids (c-CN2XCOOH, X = Cl or Br) were prepared from their esters and converted to the corresponding sodium salts. Collision-induced dissociation (CID) of the carboxylate ions led exclusively to the loss of CO2 and the resulting c-CN2X(-) ions dissociated to c-CN2 carbene at low energies. The bond dissociation energy (BDE) for c-CN2Br(-) was found to be less than 8 kcal/mol using CID of the anion generated by electrospray ionization of the carboxylate. The analogous difluoro system (CF2XCOOH/CF2X(-)/CF2) exhibits similar dissociative behavior. All experimental BDEs are in very good agreement with MP4/aug-cc-pVTZ calculations.
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Affiliation(s)
- Eva Hanzlová
- Department of Organic Chemistry, University of Chemical Technology , Technická 5, 166 28 Prague, Czech Republic
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Lin X, Ye X, Sun X, Zhang Y, Gao L, Song Z. [1,5]-Anion relay via intramolecular proton transfer to generate 3,3-bis(silyl) allyloxy lithium: a useful scaffold for syn-addition to aldehydes and ketones. Org Lett 2014; 16:1084-7. [PMID: 24499418 DOI: 10.1021/ol4036402] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A [1,5]-anion relay has been achieved in 3,3-bis(silyl) benzyl enol ether. Deprotonation at the sterically more accessible benzyl position triggers an intramolecular proton transfer to generate the thermodynamically more stable 3,3-bis(silyl) allyloxy lithium. This endo-oriented allyl anion is stable at -78 °C and undergoes diastereoselective syn-addition at the γ-position with aldehydes and ketones to give monobenzyl-substituted 1,2-diols.
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Affiliation(s)
- Xinglong Lin
- Key Laboratory of Drug-Targeting of Education Ministry and Department of Medicinal Chemistry, West China School of Pharmacy, ‡State Key Laboratory of Biotherapy, West China Hospital, Sichuan University , Chengdu 610041, P. R. China
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Rijs NJ, Yoshikai N, Nakamura E, O’Hair RAJ. Unraveling Organocuprate Complexity: Fundamental Insights into Intrinsic Group Transfer Selectivity in Alkylation Reactions. J Org Chem 2014; 79:1320-34. [DOI: 10.1021/jo4027325] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
| | - Naohiko Yoshikai
- Division
of Chemistry and Biological Chemistry, School of Physical and Mathematical
Sciences, Nanyang Technological University, Singapore 637371
| | - Eiichi Nakamura
- Department
of Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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