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Wu X, Hu Y, Zhang S, Xie J. Shapeshifting Nucleophiles HO -(NH 3) n React with Methyl Chloride. J Phys Chem A 2024; 128:2556-2564. [PMID: 38530765 DOI: 10.1021/acs.jpca.3c07553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
The microsolvated anions HO-(NH3)n were found to induce new nucleophile NH2-(H2O)(NH3)n-1 via intramolecular proton transfer. Hence, the ion-molecule nucleophilic substitution (SN2) reaction between CH3Cl and these shapeshifting nucleophiles lead to both the HO- path and NH2- path, meaning that the respective attacking nucleophile is HO- or NH2-. The CCSD(T) level of calculation was performed to characterize the potential energy surfaces. Calculations indicate that the HO- species are lower in energy than the NH2- species, and the SN2 reaction barriers are lower for the HO- path than the NH2--path. Incremental solvation increases the barrier for both paths. Comparison between HO-(NH3)n and HOO-(NH3)n confirmed the existence of an α-effect under microsolvated conditions. Comparison between HO-(NH3)n and HO-(H2O)n indicated that the more polarized H2O stabilizes the nucleophiles more than NH3, and thus, the hydrated systems have higher SN2 reaction barriers. The aforementioned barrier changes can be explained by the differential stabilization of the nucleophile and HOMO levels upon solvation, thus affecting the HOMO-LUMO interaction between the nucleophile and substrate. For the same kind of nucleophilic attacking atom, O or N, the reaction barrier has a good linear correlation with the HOMO level of the nucleophiles. Hence, the HOMO level or the binding energy of microsolvated nucleophiles is a good indicator to evaluate the order of barrier heights. This work expands our understanding of the microsolvation effect on prototype SN2 reactions beyond the water solvent.
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Affiliation(s)
- Xiangyu Wu
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yang Hu
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Shaowen Zhang
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Jing Xie
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
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2
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Hu Y, Wu X, Xie J. Nucleophilic substitution reactions of microsolvated hydroperoxide anion HOO -(NH 3) n with methyl chloride and comparison between ammonia and water as the solvent. Phys Chem Chem Phys 2023; 25:1947-1956. [PMID: 36541372 DOI: 10.1039/d2cp04693h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Similar to microhydrated hydroperoxide anion HOO-(H2O)n, the HOO-(NH3)n=1-3 anion can induce alternative nucleophiles by proton transfer (PT) from the solvent molecule NH3. The PT-induced species NH2-(H2O2)(NH3)n-1 is higher in energy than HOO-(NH3)n, obeying the proton affinity (PA) prediction that HOO- has a higher PA than NH2-. The potential energy profile of HOO-(NH3)n reacting with CH3Cl shows that the transition states of the traditional HOO--SN2 pathway are ∼10 kcal mol-1 lower in energy than those of the PT-induced NH2--SN2 pathway, indicating the latter path is unlikely to compete. The differential solvation energy for reactants and transition states with incremental solvation increases the barrier height of both HOO--/NH2--SN2 pathways and makes the transition structures more product-like. For HOO-(sol)n + CH3Cl → CH3OOH + Cl-(sol)n reactions, the barrier heights for sol = H2O are higher than those for sol = NH3, because H2O is more polar than NH3, and the electrostatic interaction is strengthened, hence H2O molecules stabilize the microsolvated nucleophiles more. In addition, because the H2O molecule is a better proton donor than the NH3 molecule, the PT-induced HO-SN2 pathway is more likely to compete with the HOO-SN2 pathway. The HOMO level of nucleophiles, which negatively correlates with the SN2 barrier heights, is found to be a good descriptor to predict the SN2 barrier height of a microsolvated system with the same attacking nucleophile. This work adds to our understanding of the differential solvent effect on the prototype ion-molecule SN2 reactions.
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Affiliation(s)
- Yang Hu
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Xiangyu Wu
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Jing Xie
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
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3
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Wu X, Liu Q, Zhao Y, Zhang L, Du J. Reaction Kinetic Model Considering the Solvation Effect Based on the FMO Theory and Deep Learning. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c01473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Xinyuan Wu
- Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Institute of Chemical Process Systems Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian116024, China
| | - Qilei Liu
- Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Institute of Chemical Process Systems Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian116024, China
| | - Yujing Zhao
- Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Institute of Chemical Process Systems Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian116024, China
| | - Lei Zhang
- Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Institute of Chemical Process Systems Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian116024, China
| | - Jian Du
- Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Institute of Chemical Process Systems Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian116024, China
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4
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Edeleva M, Van Steenberge PH, Sabbe MK, D’hooge DR. Connecting Gas-Phase Computational Chemistry to Condensed Phase Kinetic Modeling: The State-of-the-Art. Polymers (Basel) 2021; 13:3027. [PMID: 34577928 PMCID: PMC8467432 DOI: 10.3390/polym13183027] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 02/06/2023] Open
Abstract
In recent decades, quantum chemical calculations (QCC) have increased in accuracy, not only providing the ranking of chemical reactivities and energy barriers (e.g., for optimal selectivities) but also delivering more reliable equilibrium and (intrinsic/chemical) rate coefficients. This increased reliability of kinetic parameters is relevant to support the predictive character of kinetic modeling studies that are addressing actual concentration changes during chemical processes, taking into account competitive reactions and mixing heterogeneities. In the present contribution, guidelines are formulated on how to bridge the fields of computational chemistry and chemical kinetics. It is explained how condensed phase systems can be described based on conventional gas phase computational chemistry calculations. Case studies are included on polymerization kinetics, considering free and controlled radical polymerization, ionic polymerization, and polymer degradation. It is also illustrated how QCC can be directly linked to material properties.
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Affiliation(s)
- Mariya Edeleva
- Laboratory for Chemical Technology (LCT), Ghent University, Technologiepark 125, 9052 Zwijnaarde, Belgium; (P.H.M.V.S.); (M.K.S.)
| | - Paul H.M. Van Steenberge
- Laboratory for Chemical Technology (LCT), Ghent University, Technologiepark 125, 9052 Zwijnaarde, Belgium; (P.H.M.V.S.); (M.K.S.)
| | - Maarten K. Sabbe
- Laboratory for Chemical Technology (LCT), Ghent University, Technologiepark 125, 9052 Zwijnaarde, Belgium; (P.H.M.V.S.); (M.K.S.)
- Industrial Catalysis and Adsorption Technology (INCAT), Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium
| | - Dagmar R. D’hooge
- Laboratory for Chemical Technology (LCT), Ghent University, Technologiepark 125, 9052 Zwijnaarde, Belgium; (P.H.M.V.S.); (M.K.S.)
- Centre for Textile Science and Engineering (CTSE), Ghent University, Technologiepark 70a, 9052 Zwijnaarde, Belgium
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5
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Fu Y, Bernasconi L, Liu P. Ab Initio Molecular Dynamics Simulations of the S N1/S N2 Mechanistic Continuum in Glycosylation Reactions. J Am Chem Soc 2021; 143:1577-1589. [PMID: 33439656 PMCID: PMC8162065 DOI: 10.1021/jacs.0c12096] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We report a computational approach to evaluate the reaction mechanisms of glycosylation using ab initio molecular dynamics (AIMD) simulations in explicit solvent. The reaction pathways are simulated via free energy calculations based on metadynamics and trajectory simulations using Born-Oppenheimer molecular dynamics. We applied this approach to investigate the mechanisms of the glycosylation of glucosyl α-trichloroacetimidate with three acceptors (EtOH, i-PrOH, and t-BuOH) in three solvents (ACN, DCM, and MTBE). The reactants and the solvents are treated explicitly using density functional theory. We show that the profile of the free energy surface, the synchronicity of the transition state structure, and the time gap between leaving group dissociation and nucleophile association can be used as three complementary indicators to describe the glycosylation mechanism within the SN1/SN2 continuum for a given reaction. This approach provides a reliable means to rationalize and predict reaction mechanisms and to estimate lifetimes of oxocarbenium intermediates and their dependence on the glycosyl donor, acceptor, and solvent environment.
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Affiliation(s)
- Yue Fu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Leonardo Bernasconi
- Center for Research Computing, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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Rohrbach S, Smith AJ, Pang JH, Poole DL, Tuttle T, Chiba S, Murphy JA. Concerted Nucleophilic Aromatic Substitution Reactions. Angew Chem Int Ed Engl 2019; 58:16368-16388. [PMID: 30990931 PMCID: PMC6899550 DOI: 10.1002/anie.201902216] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/11/2019] [Indexed: 12/31/2022]
Abstract
Recent developments in experimental and computational chemistry have identified a rapidly growing class of nucleophilic aromatic substitutions that proceed by concerted (cSN Ar) rather than classical, two-step, SN Ar mechanisms. Whereas traditional SN Ar reactions require substantial activation of the aromatic ring by electron-withdrawing substituents, such activating groups are not mandatory in the concerted pathways.
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Affiliation(s)
- Simon Rohrbach
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
| | - Andrew J. Smith
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
| | - Jia Hao Pang
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological UniversitySingapore637371Singapore
| | - Darren L. Poole
- GlaxoSmithKline Medicines Research CentreGunnels Wood RoadStevenageSG1 2NYUK
| | - Tell Tuttle
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
| | - Shunsuke Chiba
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological UniversitySingapore637371Singapore
| | - John A. Murphy
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
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7
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Rohrbach S, Smith AJ, Pang JH, Poole DL, Tuttle T, Chiba S, Murphy JA. Konzertierte nukleophile aromatische Substitutionen. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902216] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Simon Rohrbach
- Department of Pure and Applied ChemistryUniversity of Strathclyde 295 Cathedral Street Glasgow G1 1XL Großbritannien
| | - Andrew J. Smith
- Department of Pure and Applied ChemistryUniversity of Strathclyde 295 Cathedral Street Glasgow G1 1XL Großbritannien
| | - Jia Hao Pang
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapur
| | - Darren L. Poole
- GlaxoSmithKline Medicines Research Centre Gunnels Wood Road Stevenage SG1 2NY Großbritannien
| | - Tell Tuttle
- Department of Pure and Applied ChemistryUniversity of Strathclyde 295 Cathedral Street Glasgow G1 1XL Großbritannien
| | - Shunsuke Chiba
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapur
| | - John A. Murphy
- Department of Pure and Applied ChemistryUniversity of Strathclyde 295 Cathedral Street Glasgow G1 1XL Großbritannien
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8
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Enneiymy M, Le Drian C, Becht JM. Green reusable Pd nanoparticles embedded in phytochemical resins for mild hydrogenations of nitroarenes. NEW J CHEM 2019. [DOI: 10.1039/c9nj04474d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reusable biosourced Pd NPs are prepared and used under environment-friendly conditions for mild and chemospecific hydrogenations of nitroarenes.
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Affiliation(s)
- Mohamed Enneiymy
- Université de Haute-Alsace
- CNRS
- IS2M UMR 7361
- F-68100 Mulhouse
- France
| | - Claude Le Drian
- Université de Haute-Alsace
- CNRS
- IS2M UMR 7361
- F-68100 Mulhouse
- France
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9
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Van Lommel R, Moors SLC, De Proft F. Solvent and Autocatalytic Effects on the Stabilisation of the σ-Complex during Electrophilic Aromatic Chlorination. Chemistry 2018. [PMID: 29516648 DOI: 10.1002/chem.201800385] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The solvent and autocatalytic effects of the electrophilic aromatic chlorination of benzene are studied using a combined approach of static calculations and ab initio metadynamics simulations. Different possible reaction pathways are investigated and the influence of the solvents (CCl4 , acetonitrile and acetic acid) is thoroughly assessed. Our results show that the stability and lifetime of a charged σ-complex is increased by electrostatic stabilisation effects of the environment, which can originate from catalytic HCl, solvating effects of polar solvents (acetonitrile), or specific hydrogen bonding interactions with the solvent (acetic acid). Metadynamics simulations reveal a new chlorine addition mechanism explaining the autocatalytic effects of the reaction. The strength of combining static calculations and metadynamics simulations is highlighted, which provide complementary insight into chemical reactions in solvent.
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Affiliation(s)
- Ruben Van Lommel
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium
| | - Samuel L C Moors
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium
| | - Frank De Proft
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium
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10
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11
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Um IH, Kim MY, Dust JM. Medium effect (water versus MeCN) on reactivity and reaction pathways for the SNAr reaction of 1-aryloxy-2,4-dinitrobenzenes with cyclic secondary amines. CAN J CHEM 2017. [DOI: 10.1139/cjc-2017-0454] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A kinetic study on SNAr reactions of 1-aryloxy-2,4-dinitrobenzenes (1a–1h) with a series of cyclic secondary amines in 80 mol% water – 20 mol% DMSO at 25.0 ± 0.1 °C is reported. The plots of kobsd versus amine concentration curve upward except for the reactions of substrates possessing a strong electron-withdrawing group in the leaving aryloxide with strongly basic piperidine. The curved plots indicate that the reactions proceed through both uncatalytic and catalytic routes. Linear Brønsted-type plots have been obtained for the uncatalyzed and catalyzed reactions of 1-(4-nitrophenoxy)-2,4-dinitrobenzene (1a) with βnuc = 0.84 and 0.78, respectively. The Yukawa–Tsuno plot for the uncatalyzed reactions of 1a–1h with piperidine results in an excellent linear correlation with ρ = 1.66 and r = 0.31. In contrast, rate constants for catalyzed reactions are independent of the electronic nature of the substituent in the leaving group. The current SNAr reactions have been proposed to proceed via a zwitterionic intermediate (MC±) that partitions to products through uncatalytic and catalytic routes. The catalyzed reaction from MC± has been concluded to proceed through a concerted mechanism with a six-membered cyclic transition state (TScycl) rather than via a stepwise pathway with a discrete anionic intermediate (MC−), the traditionally accepted mechanism. Medium effects on the reactivity and reaction mechanism are discussed. Particularly, hydrogen bonding of the amines to water precludes formation of kinetically significant dimers found in some aprotic solvents; no explicit role for water in the catalytic transition state is required or proposed. The specific stabilization of the leaving aryloxides substituted with strong electron-withdrawing groups accounts for the lack of the catalytic pathway in these systems (1a–1c) with piperidine nucleophile.
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Affiliation(s)
- Ik-Hwan Um
- Department of Chemistry, Ewha Womans University, Seoul 120-750, Korea
| | - Min-Young Kim
- Department of Chemistry, Ewha Womans University, Seoul 120-750, Korea
| | - Julian M. Dust
- Departments of Chemistry and Environmental Science, Grenfell Campus, Memorial University of Newfoundland, Corner Brook, NL A2H 5G4, Canada
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12
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Tretyakov EV, Fedyushin PA, Panteleeva EV, Stass DV, Bagryanskaya IY, Beregovaya IV, Bogomyakov AS. Substitution of a Fluorine Atom in Perfluorobenzonitrile by a Lithiated Nitronyl Nitroxide. J Org Chem 2017; 82:4179-4185. [PMID: 28358985 DOI: 10.1021/acs.joc.7b00144] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (1) lithium derivative was found to react with perfluorobenzonitrile (2) substituting its para-fluorine atom to form 2-(4-cyanotetrafluorophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl (3), a new nitronyl nitroxide containing a multifunctional framework of strong electron-withdrawing nature. This result shows the possibility of obtaining multifunctional nitronyl nitroxides via the interaction of paramagnetic lithium derivatives as C-nucleophiles with polyfluoroarenes activated for nucleophilic substitution. The reaction regioselectivity is supported by the data of quantum-chemical calculations, which also show that the reaction follows a concerted pathway without formation of an intermediate. Reduction of nitronyl nitroxide 3 in system NaNO2-AcOH yielded corresponding iminonitroxide 4. Characterization of persistent radicals 3 and 4 obtained by the SNF synthetic strategy includes X-ray crystal structures, electron spin resonance data, and static magnetic-susceptibility measurements. X-ray diffraction analysis of both nitronyl nitroxide and iminonitroxide revealed a complete match of the parameters of their crystal lattices.
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Affiliation(s)
- Evgeny V Tretyakov
- N. N. Vorozhtsov Institute of Organic Chemistry , 9 Ac. Lavrentiev Avenue, Novosibirsk 630090, Russia.,Novosibirsk State University , 2 Pirogova Str., Novosibirsk 630090, Russia
| | - Pavel A Fedyushin
- N. N. Vorozhtsov Institute of Organic Chemistry , 9 Ac. Lavrentiev Avenue, Novosibirsk 630090, Russia
| | - Elena V Panteleeva
- N. N. Vorozhtsov Institute of Organic Chemistry , 9 Ac. Lavrentiev Avenue, Novosibirsk 630090, Russia.,Novosibirsk State University , 2 Pirogova Str., Novosibirsk 630090, Russia
| | - Dmitri V Stass
- Novosibirsk State University , 2 Pirogova Str., Novosibirsk 630090, Russia.,Institute of Chemical Kinetics and Combustion , 3 Institutskaya Str., Novosibirsk 630090, Russia
| | - Irina Yu Bagryanskaya
- N. N. Vorozhtsov Institute of Organic Chemistry , 9 Ac. Lavrentiev Avenue, Novosibirsk 630090, Russia.,Novosibirsk State University , 2 Pirogova Str., Novosibirsk 630090, Russia
| | - Irina V Beregovaya
- N. N. Vorozhtsov Institute of Organic Chemistry , 9 Ac. Lavrentiev Avenue, Novosibirsk 630090, Russia
| | - Artem S Bogomyakov
- International Tomography Center , 3a Institutskaya Str., Novosibirsk 630090, Russia
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13
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14
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Moors SLC, Deraet X, Van Assche G, Geerlings P, De Proft F. Aromatic sulfonation with sulfur trioxide: mechanism and kinetic model. Chem Sci 2017; 8:680-688. [PMID: 28451217 PMCID: PMC5297940 DOI: 10.1039/c6sc03500k] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/10/2016] [Indexed: 01/29/2023] Open
Abstract
Electrophilic aromatic sulfonation of benzene with sulfur trioxide is studied with ab initio molecular dynamics simulations in gas phase, and in explicit noncomplexing (CCl3F) and complexing (CH3NO2) solvent models. We investigate different possible reaction pathways, the number of SO3 molecules participating in the reaction, and the influence of the solvent. Our simulations confirm the existence of a low-energy concerted pathway with formation of a cyclic transition state with two SO3 molecules. Based on the simulation results, we propose a sequence of elementary reaction steps and a kinetic model compatible with experimental data. Furthermore, a new alternative reaction pathway is proposed in complexing solvent, involving two SO3 and one CH3NO2.
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Affiliation(s)
- Samuel L C Moors
- Eenheid Algemene Chemie (ALGC) , Vrije Universiteit Brussel (VUB) , Pleinlaan 2, 1050 Elsene , Brussels , Belgium .
| | - Xavier Deraet
- Eenheid Algemene Chemie (ALGC) , Vrije Universiteit Brussel (VUB) , Pleinlaan 2, 1050 Elsene , Brussels , Belgium .
| | - Guy Van Assche
- Physical Chemistry and Polymer Science (FYSC) , Vrije Universiteit Brussel (VUB) , Pleinlaan 2, 1050 Elsene , Brussels , Belgium
| | - Paul Geerlings
- Eenheid Algemene Chemie (ALGC) , Vrije Universiteit Brussel (VUB) , Pleinlaan 2, 1050 Elsene , Brussels , Belgium .
| | - Frank De Proft
- Eenheid Algemene Chemie (ALGC) , Vrije Universiteit Brussel (VUB) , Pleinlaan 2, 1050 Elsene , Brussels , Belgium .
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15
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De Meyer T, Ensing B, Rogge SMJ, De Clerck K, Meijer EJ, Van Speybroeck V. Acidity Constant (pK a ) Calculation of Large Solvated Dye Molecules: Evaluation of Two Advanced Molecular Dynamics Methods. Chemphyschem 2016; 17:3447-3459. [PMID: 27570194 PMCID: PMC5129556 DOI: 10.1002/cphc.201600734] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Indexed: 11/14/2022]
Abstract
pH‐Sensitive dyes are increasingly applied on polymer substrates for the creation of novel sensor materials. Recently, these dye molecules were modified to form a covalent bond with the polymer host. This had a large influence on the pH‐sensitive properties, in particular on the acidity constant (pKa). Obtaining molecular control over the factors that influence the pKa value is mandatory for the future intelligent design of sensor materials. Herein, we show that advanced molecular dynamics (MD) methods have reached the level at which the pKa values of large solvated dye molecules can be predicted with high accuracy. Two MD methods were used in this work: steered or restrained MD and the insertion/deletion scheme. Both were first calibrated on a set of phenol derivatives and afterwards applied to the dye molecule bromothymol blue. Excellent agreement with experimental values was obtained, which opens perspectives for using these methods for designing dye molecules.
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Affiliation(s)
- Thierry De Meyer
- Center for Molecular Modeling, Ghent University, Technologiepark 903, 9052, Zwijnaarde, Belgium.,Department of Textiles, Ghent University, Technologiepark 907, 9052, Zwijnaarde, Belgium
| | - Bernd Ensing
- Amsterdam Center for Multiscale Modeling and Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Sven M J Rogge
- Center for Molecular Modeling, Ghent University, Technologiepark 903, 9052, Zwijnaarde, Belgium
| | - Karen De Clerck
- Department of Textiles, Ghent University, Technologiepark 907, 9052, Zwijnaarde, Belgium
| | - Evert Jan Meijer
- Amsterdam Center for Multiscale Modeling and Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
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