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Gál DR, Papp D, Czakó G. Benchmark ab initio characterization of the multi-channel Cl + CH 3X [X = F, Cl, Br, I] reactive potential energy surfaces. Phys Chem Chem Phys 2024; 26:17695-17706. [PMID: 38869051 DOI: 10.1039/d4cp01578a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
We determine benchmark geometries and relative energies for the stationary points of the Cl + CH3X [X = F, Cl, Br, I] reactions. We consider four possible reaction pathways: hydrogen abstraction, hydrogen substitution, halogen abstraction, and halogen substitution, where the substitution processes can proceed via either Walden inversion or front-side attack. We perform geometry optimizations and obtain harmonic vibrational frequencies at the explicitly-correlated UCCSD(T)-F12b/aug-cc-pVTZ level of theory, followed by UCCSD(T)-F12b/aug-cc-pVQZ single-point computations to make finite-basis-set error negligible. To reach chemical (<1 kcal mol-1), or even subchemical (<0.5 kcal mol-1) accuracy, we include core-correlation, scalar relativistic, post-(T), spin-orbit-splitting and zero-point-energy contributions, as well, in the relative energies of all the stationary points. Our benchmark 0 K reaction enthalpies are compared to available experimental results and show good agreement. The stationary-point structures and energetics are interpreted in terms of Hammond's postulate and used to make predictions related to the dynamical behavior of these reactive systems.
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Affiliation(s)
- Dorina R Gál
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Dóra Papp
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
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2
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Tasi DA, Czakó G. Benchmark ab initio characterization of the complex potential energy surfaces of the HOO - + CH 3Y [Y = F, Cl, Br, I] reactions. Phys Chem Chem Phys 2024; 26:16048-16059. [PMID: 38779842 DOI: 10.1039/d4cp01071j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
The α-effect is a well-known phenomenon in organic chemistry, and is related to the enhanced reactivity of nucleophiles involving one or more lone-pair electrons adjacent to the nucleophilic center. The gas-phase bimolecular nucleophilic substitution (SN2) reactions of α-nucleophile HOO- with methyl halides have been thoroughly investigated experimentally and theoretically; however, these investigations have mainly focused on identifying and characterizing the α-effect of HOO-. Here, we perform the first comprehensive high-level ab initio mapping for the HOO- + CH3Y [Y = F, Cl, Br and I] reactions utilizing the modern explicitly-correlated CCSD(T)-F12b method with the aug-cc-pVnZ [n = 2-4] basis sets. The present ab initio characterization considers five distinct product channels of SN2: (CH3OOH + Y-), proton abstraction (CH2Y- + H2O2), peroxide ion substitution (CH3OO- + HY), SN2-induced elimination (CH2O + HY + HO-) and SN2-induced rearrangement (CH2(OH)O- + HY). Moreover, besides the traditional back-side attack Walden inversion, the pathways of front-side attack, double inversion and halogen-bond complex formation have also been explored for SN2. With regard to the Walden inversion of HOO- + CH3Cl, the previously unaddressed discrepancies concerning the geometry of the corresponding transition state are clarified. For the HOO- + CH3F reaction, the recently identified SN2-induced elimination is found to be more exothermic than the SN2 channel, submerged by ∼36 kcal mol-1. The accuracy of our high-level ab initio calculations performed in the present study is validated by the fact that our new benchmark 0 K reaction enthalpies show excellent agreement with the experimental data in nearly all cases.
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Affiliation(s)
- Domonkos A Tasi
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
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3
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Ballay B, Szűcs T, Papp D, Czakó G. Phosphorus-centered ion-molecule reactions: benchmark ab initio characterization of the potential energy surfaces of the X - + PH 2Y [X, Y = F, Cl, Br, I] systems. Phys Chem Chem Phys 2023; 25:28925-28940. [PMID: 37855143 DOI: 10.1039/d3cp03733a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
In the present work we determine the benchmark relative energies and geometries of all the relevant stationary points of the X- + PH2Y [X, Y = F, Cl, Br, I] identity and non-identity reactions using state-of-the-art electronic-structure methods. These phosphorus-centered ion-molecule reactions follow two main reaction routes: bimolecular nucleophilic substitution (SN2), leading to Y- + PH2X, and proton transfer, resulting in HX + PHY- products. The SN2 route can proceed through Walden-inversion, front-side-attack retention, and double-/multiple-inversion pathways. In addition, we also identify the following product channels: H--formation, PH2-- and PH2-formation, 1PH- and 3PH-formation, H2-formation and HY + PHX- formation. The benchmark classical relative energies are obtained by taking into account the core-correlation, scalar relativistic, and post-(T) corrections, which turn out to be necessary to reach subchemical (<1 kcal mol-1) accuracy of the results. Classical relative energies are augmented with zero-point-energy contributions to gain the benchmark adiabatic energies.
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Affiliation(s)
- Boldizsár Ballay
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Tímea Szűcs
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Dóra Papp
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
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Zhao S, Fu G, Zhen W, Yang L, Sun J, Zhang J. Reaction mechanism conversion induced by the contest of nucleophile and leaving group. Phys Chem Chem Phys 2022; 24:24146-24154. [PMID: 36168813 DOI: 10.1039/d2cp01987f] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Direct dynamic simulations have been employed to investigate the OH- + CH3Cl reaction with the chosen B3LYP/aug-cc-pVDZ method. The calculated rate coefficient for the bimolecular nucleophilic substitution reaction (SN2), 1.0 × 10-9 cm3 mol-1 s-1 at 300 K, agrees well with the experimental result of (1.3-1.6) × 10-9 cm3 mol-1 s-1. The simulations reveal that the majority of the SN2 reactions are temporarily trapped in the hydrogen-bonded complex at Ecoll = 0.89 kcal mol-1. Importantly, the influences of the leaving group and nucleophile have been discussed by comparisons of X- + CH3Y (X = F, OH; Y = Cl, I) reactions. For the X = F- reactions, the reaction probability of SN2 increases along the increased leaving group ability Cl < I, suggesting that the thermodynamic factor plays a key role. The indirect mechanisms were found to be dominant for both reactions. In contrast, for X = OH-, the fraction of SN2 drops with the enhanced leaving group ability. In particular, a dramatic transition occurs for the dominant atomic reaction mechanisms, i.e., from complex-mediated indirect to direct, implying an interesting contest between the leaving group and the nucleophile and the importance of the dynamic factors, i.e., the dipole moment, steric hindrance, and electronegativity.
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Affiliation(s)
- Siwei Zhao
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Gang Fu
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Wenqing Zhen
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Li Yang
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China. .,State Key Lab of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, P. R. China
| | - Jianmin Sun
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China. .,State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150001, P. R. China
| | - Jiaxu Zhang
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China. .,State Key Lab of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, P. R. China
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Espinosa-Garcia J, Rangel C, Corchado JC. Current Status of the X + C 2H 6 [X ≡ H, F( 2P), Cl( 2P), O( 3P), OH] Hydrogen Abstraction Reactions: A Theoretical Review. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27123773. [PMID: 35744901 PMCID: PMC9228020 DOI: 10.3390/molecules27123773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/08/2022] [Accepted: 06/08/2022] [Indexed: 12/03/2022]
Abstract
This paper is a detailed review of the chemistry of medium-size reactive systems using the following hydrogen abstraction reactions with ethane, X + C2H6 → HX + C2H5; X ≡ H, F(2P), Cl(2P), O(3P) and OH, and focusing attention mainly on the theoretical developments. These bimolecular reactions range from exothermic to endothermic systems and from barrierless to high classical barriers of activation. Thus, the topography of the reactive systems changes from reaction to reaction with the presence or not of stabilized intermediate complexes in the entrance and exit channels. The review begins with some reflections on the inherent problems in the theory/experiment comparison. When one compares kinetics or dynamics theoretical results with experimental measures, one is testing both the potential energy surface describing the nuclei motion and the kinetics or dynamics method used. Discrepancies in the comparison may be due to inaccuracies of the surface, limitations of the kinetics or dynamics methods, and experimental uncertainties that also cannot be ruled out. The paper continues with a detailed review of some bimolecular reactions with ethane, beginning with the reactions with hydrogen atoms. The reactions with halogens present a challenge owing to the presence of stabilized intermediate complexes in the entrance and exit channels and the influence of the spin-orbit states on reactivity. Reactions with O(3P) atoms lead to three surfaces, which is an additional difficulty in the theoretical study. Finally, the reactions with the hydroxyl radical correspond to a reactive system with ten atoms and twenty-four degrees of freedom. Throughout this review, different strategies in the development of analytical potential energy surfaces describing these bimolecular reactions have been critically analyzed, showing their advantages and limitations. These surfaces are fitted to a large number of ab initio calculations, and we found that a huge number of calculations leads to accurate surfaces, but this information does not guarantee that the kinetics and dynamics results match the experimental measurements.
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Tajti V, Czakó G. Vibrational mode-specific dynamics of the F - + CH 3CH 2Cl multi-channel reaction. Phys Chem Chem Phys 2022; 24:8166-8181. [PMID: 35343535 DOI: 10.1039/d2cp00685e] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate the mode-specific dynamics of the ground-state, C-Cl stretching (v10), CH2 wagging (v7), sym-CH2 stretching (v1), and sym-CH3 stretching (v3) excited F- + CH3CH2Cl(vk = 0, 1) [k = 10, 7, 1, 3] → Cl- + CH3CH2F (SN2), HF + CH3CHCl-, FH⋯Cl- + C2H4, and Cl- + HF + C2H4 (E2) reactions using a full-dimensional high-level analytical global potential energy surface and the quasi-classical trajectory method. Excitation of the C-Cl stretching, CH2 stretching, and CH2/CH3 stretching modes enhances the SN2, proton abstraction, and FH⋯Cl- and E2 channels, respectively. Anti-E2 dominates over syn-E2 (kinetic anti-E2 preference) and the thermodynamically-favored SN2 (wider reactive anti-E2 attack angle range). The direct (a) SN2, (b) proton abstraction, (c) FH⋯Cl- + C2H4, (d) syn-E2, and (e) anti-E2 channels proceed with (a) back-side/backward, (b) isotropic/forward, (c) side-on/forward, (d) front-side/forward, and (e) back-side/forward attack/scattering, respectively. The HF products are vibrationally cold, especially for proton abstraction, and their rotational excitation increases for proton abstraction, anti-E2, and syn-E2, in order. Product internal-energy and mode-specific vibrational distributions show that CH3CH2F is internally hot with significant C-F stretching and CH2 wagging excitations, whereas C2H4 is colder. One-dimensional Gaussian binning technique is proved to solve the normal mode analysis failure caused by methyl internal rotation.
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Affiliation(s)
- Viktor Tajti
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
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7
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Dékány AÁ, Kovács GZ, Czakó G. High-Level Systematic Ab Initio Comparison of Carbon- and Silicon-Centered S N2 Reactions. J Phys Chem A 2021; 125:9645-9657. [PMID: 34709818 PMCID: PMC8591615 DOI: 10.1021/acs.jpca.1c07574] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
We characterize the
stationary points along the Walden inversion,
front-side attack, and double-inversion pathways of the X– + CH3Y and X– + SiH3Y [X,
Y = F, Cl, Br, I] SN2 reactions using chemically accurate
CCSD(T)-F12b/aug-cc-pVnZ [n = D,
T, Q] levels of theory. At the carbon center, Walden inversion dominates
and proceeds via prereaction (X–···H3CY) and postreaction (XCH3···Y–) ion-dipole wells separated by a usually submerged
transition state (X–H3C–Y)−, front-side attack occurs over high barriers, double inversion is
the lowest-energy retention pathway for X = F, and hydrogen- (F–···HCH2Y) and halogen-bonded
(X–···YCH3) complexes
exist in the entrance channel. At the silicon center, Walden inversion
proceeds through a single minimum (X–SiH3–Y)−, the front-side attack is competitive via a usually
submerged transition state separating pre- and postreaction minima
having X–Si–Y angles close to 90°, double inversion
occurs over positive, often high barriers, and hydrogen- and halogen-bonded
complexes are not found. In addition to the SN2 channels
(Y– + CH3X/SiH3X), we report
reaction enthalpies for proton abstraction (HX + CH2Y–/SiH2Y–), hydride substitution
(H– + CH2XY/SiH2XY), XH···Y– complex formation (XH···Y– + 1CH2/1SiH2), and halogen
abstraction (XY + CH3–/SiH3– and XY– + CH3/SiH3).
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Affiliation(s)
- Attila Á Dékány
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Gyula Z Kovács
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
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8
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Tsutsumi T, Ono Y, Taketsugu T. Visualization of reaction route map and dynamical trajectory in reduced dimension. Chem Commun (Camb) 2021; 57:11734-11750. [PMID: 34642706 DOI: 10.1039/d1cc04667e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the quantum chemical approach, chemical reaction mechanisms are investigated based on a potential energy surface (PES). Automated reaction path search methods enable us to construct a global reaction route map containing multiple reaction paths corresponding to a series of elementary reaction processes. The on-the-fly molecular dynamics (MD) method provides a classical trajectory exploring the full-dimensional PES based on electronic structure calculations. We have developed two reaction analysis methods, the on-the-fly trajectory mapping method and the reaction space projector (ReSPer) method, by introducing a structural similarity to a pair of geometric structures and revealed dynamic aspects affecting chemical reaction mechanisms. In this review, we will present the details of these analysis methods and discuss the dynamics effects of reaction path curvature and reaction path bifurcation with applications to the CH3OH + OH- collision reaction and the Au5 cluster branching and isomerization reactions.
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Affiliation(s)
- Takuro Tsutsumi
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
| | - Yuriko Ono
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
| | - Tetsuya Taketsugu
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan. .,Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
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9
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Meyer J, Tajti V, Carrascosa E, Győri T, Stei M, Michaelsen T, Bastian B, Czakó G, Wester R. Atomistic dynamics of elimination and nucleophilic substitution disentangled for the F - + CH 3CH 2Cl reaction. Nat Chem 2021; 13:977-981. [PMID: 34373599 PMCID: PMC7611763 DOI: 10.1038/s41557-021-00753-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 06/15/2021] [Indexed: 02/08/2023]
Abstract
Chemical reaction dynamics are studied to monitor and understand the concerted motion of several atoms while they rearrange from reactants to products. When the number of atoms involved increases, the number of pathways, transition states and product channels also increases and rapidly presents a challenge to experiment and theory. Here we disentangle the dynamics of the competition between bimolecular nucleophilic substitution (SN2) and base-induced elimination (E2) in the polyatomic reaction F- + CH3CH2Cl. We find quantitative agreement for the energy- and angle-differential reactive scattering cross-sections between ion-imaging experiments and quasi-classical trajectory simulations on a 21-dimensional potential energy hypersurface. The anti-E2 pathway is most important, but the SN2 pathway becomes more relevant as the collision energy is increased. In both cases the reaction is dominated by direct dynamics. Our study presents atomic-level dynamics of a major benchmark reaction in physical organic chemistry, thereby pushing the number of atoms for detailed reaction dynamics studies to a size that allows applications in many areas of complex chemical networks and environments.
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Affiliation(s)
- Jennifer Meyer
- Institut für Ionenphysik und Angewandte Physik, Univerisität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
| | - Viktor Tajti
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Eduardo Carrascosa
- Institut für Ionenphysik und Angewandte Physik, Univerisität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
| | - Tibor Győri
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Martin Stei
- Institut für Ionenphysik und Angewandte Physik, Univerisität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
| | - Tim Michaelsen
- Institut für Ionenphysik und Angewandte Physik, Univerisität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
| | - Björn Bastian
- Institut für Ionenphysik und Angewandte Physik, Univerisität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary,
| | - Roland Wester
- Institut für Ionenphysik und Angewandte Physik, Univerisität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria,
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Tasi DA, Tokaji C, Czakó G. A benchmark ab initio study of the complex potential energy surfaces of the OH - + CH 3CH 2Y [Y = F, Cl, Br, I] reactions. Phys Chem Chem Phys 2021; 23:13526-13534. [PMID: 34132273 DOI: 10.1039/d1cp01303c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We provide the first benchmark characterization of the OH- + CH3CH2Y [Y = F, Cl, Br, I] reactions utilizing the high-level explicitly-correlated CCSD(T)-F12b method with the aug-cc-pVnZ [n = 2(D), 3(T), 4(Q)] basis sets. We explore and analyze the stationary points of the elimination (E2) and substitution (SN2) reactions, including anti-E2, syn-E2, back-side attack, front-side attack, and double inversion. In all cases, SN2 is thermodynamically more preferred than E2. In the entrance channel of SN2 a significant front-side complex formation is revealed, and in the product channel the global minimum of the title reactions is obtained at the hydrogen-bonded CH3CH2OHY- complex. Similar to the OH- + CH3Y reactions, double inversion can proceed via a notably lower-energy pathway than front-side attack, moreover, for Y = I double inversion becomes barrier-less. For the transition state of the anti-E2, a prominent ZPE effect emerges, giving an opportunity for a kinetically more favored pathway than back-side attack. In addition to SN2 and E2, other possible product channels are considered, and in most cases, the benchmark reaction enthalpies are in excellent agreement with the experimental data.
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Affiliation(s)
- Domonkos A Tasi
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
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11
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Czakó G, Győri T, Papp D, Tajti V, Tasi DA. First-Principles Reaction Dynamics beyond Six-Atom Systems. J Phys Chem A 2021; 125:2385-2393. [PMID: 33631071 PMCID: PMC8028310 DOI: 10.1021/acs.jpca.0c11531] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/05/2021] [Indexed: 11/29/2022]
Abstract
Moving beyond the six-atomic benchmark systems, we discuss the new age and future of first-principles reaction dynamics, which investigates complex, multichannel chemical reactions. We describe the methodology starting from the benchmark ab initio characterization of the stationary points, followed by full-dimensional potential energy surface (PES) developments and reaction dynamics computations. We highlight our composite ab initio approach providing benchmark stationary-point properties with subchemical accuracy, the Robosurfer program system enabling automatic PES development, and applications for the Cl + C2H6, F + C2H6, and OH- + CH3I post-six-atom reactions focusing on ab initio issues and their solutions as well as showing the excellent agreement between theory and experiment.
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Affiliation(s)
- Gábor Czakó
- MTA-SZTE Lendület
Computational Reaction Dynamics Research Group, Interdisciplinary
Excellence Centre and Department of Physical Chemistry and Materials
Science, Institute of Chemistry, University
of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Tibor Győri
- MTA-SZTE Lendület
Computational Reaction Dynamics Research Group, Interdisciplinary
Excellence Centre and Department of Physical Chemistry and Materials
Science, Institute of Chemistry, University
of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Dóra Papp
- MTA-SZTE Lendület
Computational Reaction Dynamics Research Group, Interdisciplinary
Excellence Centre and Department of Physical Chemistry and Materials
Science, Institute of Chemistry, University
of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Viktor Tajti
- MTA-SZTE Lendület
Computational Reaction Dynamics Research Group, Interdisciplinary
Excellence Centre and Department of Physical Chemistry and Materials
Science, Institute of Chemistry, University
of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Domonkos A. Tasi
- MTA-SZTE Lendület
Computational Reaction Dynamics Research Group, Interdisciplinary
Excellence Centre and Department of Physical Chemistry and Materials
Science, Institute of Chemistry, University
of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
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12
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Li J, Zhao B, Xie D, Guo H. Advances and New Challenges to Bimolecular Reaction Dynamics Theory. J Phys Chem Lett 2020; 11:8844-8860. [PMID: 32970441 DOI: 10.1021/acs.jpclett.0c02501] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Dynamics of bimolecular reactions in the gas phase are of foundational importance in combustion, atmospheric chemistry, interstellar chemistry, and plasma chemistry. These collision-induced chemical transformations are a sensitive probe of the underlying potential energy surface(s). Despite tremendous progress in past decades, our understanding is still not complete. In this Perspective, we survey the recent advances in theoretical characterization of bimolecular reaction dynamics, stimulated by new experimental observations, and identify key new challenges.
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Affiliation(s)
- Jun Li
- School of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, China
| | - Bin Zhao
- Theoretische Chemie, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, D-33615 Bielefeld, Germany
| | - Daiqian Xie
- Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
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13
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Numerical separation of the front-side attack and double-inversion retention pathways of SN2 reactions. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137780] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Gruber B, Czakó G. Benchmark ab initio characterization of the abstraction and substitution pathways of the OH + CH4/C2H6 reactions. Phys Chem Chem Phys 2020; 22:14560-14569. [DOI: 10.1039/d0cp02560g] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report benchmark ab initio stationary-point properties for the hydrogen-abstraction, hydrogen-substitution, and methyl-substitution pathways of the OH + CH4/C2H6 reactions.
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Affiliation(s)
- Balázs Gruber
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group
- Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science
- Institute of Chemistry
- University of Szeged
- Szeged H-6720
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