1
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Hansen T, Vermeeren P, Zijderveld KWJ, Bickelhaupt FM, Hamlin TA. S N 2 versus E2 Competition of Cyclic Ethers. Chemistry 2023; 29:e202301308. [PMID: 37338310 DOI: 10.1002/chem.202301308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/20/2023] [Accepted: 06/20/2023] [Indexed: 06/21/2023]
Abstract
We have quantum chemically studied the influence of ring strain on the competition between the two mechanistically different SN 2 and E2 pathways using a series of archetypal ethers as substrate in combination with a diverse set of Lewis bases (F- , Cl- , Br- , HO- , H3 CO- , HS- , H3 CS- ), using relativistic density functional theory at ZORA-OLYP/QZ4P. The ring strain in the substrate is systematically increased on going from a model acyclic ether to a 6- to 5- to 4- to 3-membered ether ring. We have found that the activation energy of the SN 2 pathway sharply decreases when the ring strain of the system is increased, thus on going from large to small cyclic ethers, the SN 2 reactivity increases. In contrast, the activation energy of the E2 pathway generally rises along this same series, that is, from large to small cyclic ethers. The opposing reactivity trends induce a mechanistic switch in the preferred reaction pathway for strong Lewis bases from E2, for large cyclic substrates, to SN 2, for small cyclic substrates. Weak Lewis bases are unable to overcome the higher intrinsic distortivity of the E2 pathway and, therefore, always favor the less distortive SN 2 reaction.
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Affiliation(s)
- Thomas Hansen
- Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS) Vrije Universiteit, Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam (The, Netherlands
| | - Pascal Vermeeren
- Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS) Vrije Universiteit, Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam (The, Netherlands
| | - Kim W J Zijderveld
- Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS) Vrije Universiteit, Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam (The, Netherlands
| | - F Matthias Bickelhaupt
- Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS) Vrije Universiteit, Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam (The, Netherlands
- Institute for Molecules and Materials (IMM), Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen (The, Netherlands
- Department of Chemical Sciences, University of Johannesburg, Auckland Park, Johannesburg, 2006, South Africa
| | - Trevor A Hamlin
- Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS) Vrije Universiteit, Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam (The, Netherlands
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2
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Zhen W, Zhao S, Fu G, Wang H, Sun J, Yang L, Zhang J. Effects of Methyl Substitution and Leaving Group on E2/S N2 Competition for Reactions of F - with RY (R = CH 3, C 2H 5, iC 3H 7, tC 4H 9; Y = Cl, I). Molecules 2023; 28:6269. [PMID: 37687098 PMCID: PMC10488877 DOI: 10.3390/molecules28176269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 08/22/2023] [Accepted: 08/24/2023] [Indexed: 09/10/2023] Open
Abstract
The competition between base-induced elimination (E2) and bimolecular nucleophilic substitution (SN2) is of significant importance in organic chemistry and is influenced by many factors. The electronic structure calculations for the gas-phase reactions of F- + RY (R = CH3, C2H5, iC3H7, tC4H9, and Y = Cl, I) are executed at the MP2 level with aug-cc-pVDZ or ECP/d basis set to investigate the α-methyl substitution effect. The variation in barrier height, reaction enthalpy, and competition of SN2/E2 as a function of methyl-substitution and leaving group ability has been emphasized. And the nature of these rules has been explored. As the degree of methyl substitution on α-carbon increases, the E2 channel becomes more competitive and dominant with R varying from C2H5, iC3H7, to tC4H9. Energy decomposition analysis offers new insights into the competition between E2 and SN2 processes, which suggests that the drop in interaction energy with an increasing degree of substitution cannot compensate for the rapid growth of preparation energy, leading to a rapid increase in the SN2 energy barrier. By altering the leaving group from Cl to I, the barriers of both SN2 and E2 monotonically decrease, and, with the increased number of substituents, they reduce more dramatically, which is attributed to the looser transition state structures with the stronger leaving group ability. Interestingly, ∆E0‡ exhibits a positive linear correlation with reaction enthalpy (∆H) and halogen electronegativity. With the added number of substituents, the differences in ∆E0‡ and ∆H between Y = Cl and I likewise exhibit good linearity.
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Affiliation(s)
| | | | | | | | | | - Li Yang
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China; (W.Z.); (S.Z.); (G.F.); (H.W.); (J.S.)
| | - Jiaxu Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China; (W.Z.); (S.Z.); (G.F.); (H.W.); (J.S.)
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3
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Dékány AÁ, Czakó G. Exploring the versatile reactivity of the F- + SiH3Cl system on a full-dimensional coupled-cluster potential energy surface. J Chem Phys 2023; 158:2895234. [PMID: 37290077 DOI: 10.1063/5.0153083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 05/18/2023] [Indexed: 06/10/2023] Open
Abstract
We develop a full-dimensional analytical potential energy surface (PES) for the F- + SiH3Cl reaction using Robosurfer for automatically sampling the configuration space, the robust [CCSD-F12b + BCCD(T) - BCCD]/aug-cc-pVTZ composite level of theory for computing the energy points, and the permutationally invariant polynomial method for fitting. Evolution of the fitting error and the percentage of the unphysical trajectories are monitored as a function of the iteration steps/number of energy points and polynomial order. Quasi-classical trajectory simulations on the new PES reveal rich dynamics resulting in high-probability SN2 (SiH3F + Cl-) and proton-transfer (SiH2Cl- + HF) products as well as several lower-probability channels, such as SiH2F- + HCl, SiH2FCl + H-, SiH2 + FHCl-, SiHFCl- + H2, SiHF + H2 + Cl-, and SiH2 + HF + Cl-. The Walden-inversion and front-side-attack-retention SN2 pathways are found to be competitive, producing nearly racemic products at high collision energies. The detailed atomic-level mechanisms of the various reaction pathways and channels as well as the accuracy of the analytical PES are analyzed along representative trajectories.
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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
| | - 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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4
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Qin J, Liu Y, Li J. Quantitative Dynamics of Paradigmatic SN2 reaction OH− + CH3F on Accurate Full-Dimensional Potential Energy Surface. J Chem Phys 2022; 157:124301. [DOI: 10.1063/5.0112228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The bimolecular reaction between OH− and CH3F is not just a prototypical SN2 process but also has three other product channels. Here, we develop an accurate full-dimensional potential energy surface (PES) based on 191 193 points calculated at the level CCSD(T)-F12a/aug-cc-pVTZ. A detailed dynamics and mechanism analysis were carried out on this PES by using the quasi-classical trajectory approach. It is verified that the trajectories do not follow the minimum energy path (MEP) but directly dissociate to F− and CH3OH. In addition, a new transition state for proton exchange and a new product complex CH2F−‧‧‧H2O for proton abstraction were discovered. The trajectories avoid the transition state or this complex, instead dissociate to H2O and CH2F− directly through the ridge regions of the MEP before the transition state. These non-MEP dynamics become more pronounced at high collision energies. Detailed dynamics simulations provide new insights into the atomic-level mechanisms of the title reaction thanks to the new chemically accurate PES with the aid of the machine learning.
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Affiliation(s)
- Jie Qin
- Chemistry and Chemical Engineering, Chongqing University Department of Chemical Engineering, China
| | | | - Jun Li
- School of Chemistry and Chemical Engineering, Chongqing University, China
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5
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Győri T, Czako G. ManyHF: A pragmatic automated method of finding lower-energy Hartree−Fock solutions for potential energy surface development. J Chem Phys 2022; 156:071101. [DOI: 10.1063/5.0080817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Tibor Győri
- Chemistry, University of Szeged Faculty of Science and Informatics, Hungary
| | - Gabor Czako
- Chemistry, University of Szeged Faculty of Science and Informatics, Hungary
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6
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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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7
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Vermeeren P, Hansen T, Jansen P, Swart M, Hamlin TA, Bickelhaupt FM. A Unified Framework for Understanding Nucleophilicity and Protophilicity in the S N 2/E2 Competition. Chemistry 2020; 26:15538-15548. [PMID: 32866336 PMCID: PMC7756690 DOI: 10.1002/chem.202003831] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Indexed: 11/11/2022]
Abstract
The concepts of nucleophilicity and protophilicity are fundamental and ubiquitous in chemistry. A case in point is bimolecular nucleophilic substitution (SN 2) and base-induced elimination (E2). A Lewis base acting as a strong nucleophile is needed for SN 2 reactions, whereas a Lewis base acting as a strong protophile (i.e., base) is required for E2 reactions. A complicating factor is, however, the fact that a good nucleophile is often a strong protophile. Nevertheless, a sound, physical model that explains, in a transparent manner, when an electron-rich Lewis base acts as a protophile or a nucleophile, which is not just phenomenological, is currently lacking in the literature. To address this fundamental question, the potential energy surfaces of the SN 2 and E2 reactions of X- +C2 H5 Y model systems with X, Y = F, Cl, Br, I, and At, are explored by using relativistic density functional theory at ZORA-OLYP/TZ2P. These explorations have yielded a consistent overview of reactivity trends over a wide range in reactivity and pathways. Activation strain analyses of these reactions reveal the factors that determine the shape of the potential energy surfaces and hence govern the propensity of the Lewis base to act as a nucleophile or protophile. The concepts of "characteristic distortivity" and "transition state acidity" of a reaction are introduced, which have the potential to enable chemists to better understand and design reactions for synthesis.
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Affiliation(s)
- Pascal Vermeeren
- Department of Theoretical ChemistryAmsterdam Institute of, Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale, Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081HVAmsterdamThe Netherlands
| | - Thomas Hansen
- Department of Theoretical ChemistryAmsterdam Institute of, Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale, Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081HVAmsterdamThe Netherlands
- Leiden Institute of ChemistryLeiden UniversityEinsteinweg 55, 2333CCLeidenThe Netherlands
| | - Paul Jansen
- Department of Theoretical ChemistryAmsterdam Institute of, Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale, Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081HVAmsterdamThe Netherlands
- Laboratory of Physical ChemistryETH ZurichVladimir-Prelog-Weg 28093ZurichSwitzerland
| | - Marcel Swart
- ICREAPg. Lluís Companys 2308010BarcelonaSpain
- IQCC & Dept. QuímicaUniversitat de GironaCampus Montilivi (Ciències)17003GironaSpain
| | - Trevor A. Hamlin
- Department of Theoretical ChemistryAmsterdam Institute of, Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale, Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081HVAmsterdamThe Netherlands
| | - F. Matthias Bickelhaupt
- Department of Theoretical ChemistryAmsterdam Institute of, Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale, Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081HVAmsterdamThe Netherlands
- Institute for Molecules and MaterialsRadboud UniversityHeyendaalseweg 1356525AJNijmegenThe Netherlands
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8
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Papp P, Czakó G. Rotational Mode Specificity in the F - + CH 3I( v = 0, JK) S N2 and Proton-Transfer Reactions. J Phys Chem A 2020; 124:8943-8948. [PMID: 33054214 PMCID: PMC7604870 DOI: 10.1021/acs.jpca.0c08043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Quasiclassical
trajectory computations are performed for the F– + CH3I(v = 0, JK) →
I– + CH3F (SN2) and HF + CH2I– (proton-transfer)
reactions considering initial rotational states characterized by J = {0, 2, 4, 6, 8, 12, and 16} and K =
{0 and J} in the 1–30 kcal/mol collision energy
(Ecoll) range. Tumbling rotation (K = 0) counteracts orientation effects, thereby hindering
the SN2 reactivity by about 15% for J =
16 in the 1–15 kcal/mol Ecoll range
and has a negligible effect on proton transfer. Spinning about the
C–I bond (K = J), which is
21 times faster than tumbling, makes the reactions more direct, inhibiting
the SN2 reactivity by 25% in some cases, whereas significantly
enhancing the proton-transfer channel by a factor of 2 at Ecoll = 15 kcal/mol due to the fact that the
spinning-induced centrifugal force hinders complex formation by breaking
H-bonds and activates C–H bond cleavage, thereby promoting
proton abstraction on the expense of substitution. At higher Ecoll, as the reactions become more direct, the
rotational effects are diminishing.
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Affiliation(s)
- Paszkál 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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9
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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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10
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McLaurin PM, Morales JA. Electron nuclear dynamics of H + + CO 2 (000) → H + + CO 2 ( v1v2v3) at ELab = 20.5-30 eV with coherent-states quantum reconstruction procedure. Phys Chem Chem Phys 2020; 22:19549-19559. [PMID: 32869775 PMCID: PMC7501211 DOI: 10.1039/d0cp03722b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2023]
Abstract
The simplest-level electron nuclear dynamics (SLEND) method with the coherent-states (CSs) quantum reconstruction procedure (CSQRP) is applied to the scattering system H+ + CO2 (000) → H+ + CO2 (v1v2v3) at ELab = 20.5-30 eV. Relevant for astrophysics, atmospheric chemistry and proton cancer therapy, this system undergoes collision-induced vibrational excitations in CO2. SLEND is a time-dependent, variational, direct, and non-adiabatic method that adopts a classical-mechanics description for nuclei and a single-determinantal wavefunction for electrons. The CSQRP employs the canonical CS to reconstruct quantum state-to-state vibrational properties from the SLEND classical nuclear dynamics. Overall, the calculated collision-induced vibrational properties agree well with experimental data. SLEND total differential cross sections (DCSs) agree remarkably well with their experimental counterparts and accurately display rainbow scattering angles structures. SLEND averaged target excitation energies for vibrational + rotational and rotational motions exhibit reasonable and good agreements with experimental data, respectively. These properties show that rotational excitation is low and that the asymmetric stretch normal mode of CO2 is much more excited than the others. SLEND/CSQRP state-to-state vibrational DCSs agree reasonably well with the sparse experimental data for final states v1v2v3 = 000-002, but less satisfactorily for 003. These DCSs also accurately display rainbow scattering angles structures. Finally, SLEND/CSQRP vibrational proton energy loss spectra agree remarkably well with their experimental counterparts for various final vibrational states of CO2, collisions energies and scattering angles. Present results demonstrate the accuracy of SLEND/CSQRP to predict state-to-state vibrational properties in scattering systems with multiple normal modes.
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Affiliation(s)
- Patrick M McLaurin
- Department of Chemistry and Biochemistry, Texas Tech University, PO Box 41061, Lubbock, TX 79409-1061, USA.
| | - Jorge A Morales
- Department of Chemistry and Biochemistry, Texas Tech University, PO Box 41061, Lubbock, TX 79409-1061, USA.
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11
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Li Y, Li Y, Wang D. The importance of the composite mechanisms with two transition states in the F - + NH 2I S N2 reaction. Phys Chem Chem Phys 2020; 22:12929-12938. [PMID: 32453309 DOI: 10.1039/d0cp01942a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dynamics of the bimolecular nucleophilic substitution (SN2) reactions at nitrogen are less understood than those of their corresponding reactions at carbon. In this paper, we report an ab initio molecular dynamics approach to investigate the reaction mechanisms of the F- + NH2I SN2 reaction at nitrogen. We found not only the one-transition-state mechanisms, but also the composite mechanisms with two and three transition states. For the two-transition-state mechanisms, the double inversion mechanism and the proton-abstraction roundabout followed by the backside-attack reaction mechanism have been reported before; but we discovered that there is also a new, front-side attack followed by the backside-attack Walden-inversion mechanism. Furthermore, a composite mechanism with three transition states also shows up in the reactive trajectories. Our results show that, as the collision energy increases, the SN2 reactivity decreases, and the proton-abstraction reactivity increases. The two-transition-state mechanisms, especially the double-inversion mechanism, make the largest contribution to the SN2 reactivity, followed then by the one-transition-state mechanisms, with the three-transition-state mechanism contributing the least. The potential energy profiles of the reaction mechanisms are characterized at the CCSD(T)/aug-cc-pVTZ(PP) level of theory. The analysis on stationary points shows that the proton-abstraction inversion transition state is ∼12.4 kcal mol-1 lower than the Walden-inversion transition state in contrast to the corresponding reaction at carbon F- + CH3I, in which the former is ∼26.1 kcal mol-1 higher than the latter. This might explain why the composite mechanism of the double inversion mechanism contributes the most to the SN2 reactivity in the F- + NH2I reaction.
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Affiliation(s)
- Yan Li
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, Shandong, China.
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12
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Czakó G, Győri T, Olasz B, Papp D, Szabó I, Tajti V, Tasi DA. Benchmark ab initio and dynamical characterization of the stationary points of reactive atom + alkane and SN2 potential energy surfaces. Phys Chem Chem Phys 2020; 22:4298-4312. [DOI: 10.1039/c9cp04944d] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We review composite ab initio and dynamical methods and their applications to characterize stationary points of atom/ion + molecule reactions.
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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
- Szeged H-6720
| | - 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
- Szeged H-6720
| | - Balázs Olasz
- 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
| | - 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
- Szeged H-6720
| | - István Szabó
- 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
| | - 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
- Szeged H-6720
| | - 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
- Szeged H-6720
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13
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Győri T, Czakó G. Automating the Development of High-Dimensional Reactive Potential Energy Surfaces with the robosurfer Program System. J Chem Theory Comput 2019; 16:51-66. [DOI: 10.1021/acs.jctc.9b01006] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- 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
| | - 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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14
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Zhang Y, Zhou X, Jiang B. Bridging the Gap between Direct Dynamics and Globally Accurate Reactive Potential Energy Surfaces Using Neural Networks. J Phys Chem Lett 2019; 10:1185-1191. [PMID: 30802067 DOI: 10.1021/acs.jpclett.9b00085] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Direct dynamics simulations become increasingly popular in studying reaction dynamics for complex systems where analytical potential energy surfaces (PESs) are unavailable. Yet, the number and/or the propagation time of trajectories are often limited by high computational costs, and numerous energies and forces generated on-the-fly become wasted after simulations. We demonstrate here an example of reusing only a very small portion of existing direct dynamics data to reconstruct a 90-dimensional globally accurate reactive PES describing the interaction of CO2 with a movable Ni(100) surface based on a machine learning approach. In addition to reproducing previous results with much better statistics, we predict scattering probabilities of CO2 at the state-to-state level, which is extremely demanding for direct dynamics. We propose this unified way to investigate gaseous and gas-surface reactions of medium size, initiating with hundreds of preliminary direct dynamics trajectories, followed by low-cost and high-quality simulations on full-dimensional analytical PESs.
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Affiliation(s)
- Yaolong Zhang
- Hefei National Laboratory for Physical Science at the Microscale, Department of Chemical Physics, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Xueyao Zhou
- Hefei National Laboratory for Physical Science at the Microscale, Department of Chemical Physics, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Bin Jiang
- Hefei National Laboratory for Physical Science at the Microscale, Department of Chemical Physics, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes , University of Science and Technology of China , Hefei , Anhui 230026 , China
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15
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Castiñeira Reis M, López CS, Nieto Faza O, Tantillo DJ. Pushing the limits of concertedness. A waltz of wandering carbocations. Chem Sci 2019; 10:2159-2170. [PMID: 30881640 PMCID: PMC6385557 DOI: 10.1039/c8sc03567a] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 12/10/2018] [Indexed: 12/21/2022] Open
Abstract
Among the array of complex terpene-forming carbocation cyclization/rearrangement reactions, the so-called "triple shift" reactions are among the most unexpected. Such reactions involve the asynchronous combination of three 1,n-shifts into a concerted process, e.g., a 1,2-alkyl shift followed by a 1,3-hydride shift followed by a second 1,2-alkyl shift. This type of reaction so far has been proposed to occur during the biosynthesis of diterpenes and the sidechains of sterols. Here we describe efforts to push the limits of concertedness in this type of carbocation reaction by designing, and characterizing with quantum chemical computations, systems that could couple additional 1,n-shift events to a triple shift leading, in principle to quadruple, pentuple, etc. shifts. While our designs did not lead to clear-cut examples of quadruple, etc. shifts, they did lead to reactions with surprisingly flat energy surfaces where more than five chemical events connect reactants and plausible products. Ab initio molecular dynamics simulations demonstrate that the formal minima on these surfaces interchange on short timescales, both with each other and with additional unexpected structures, allowing us a glimpse into a very complex manifold that allows ready access to great structural diversity.
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Affiliation(s)
- Marta Castiñeira Reis
- Departamento de Química Orgánica , Universidade de Vigo , Lagoas-Marcosende , 36310 , Vigo , Spain
| | - Carlos Silva López
- Departamento de Química Orgánica , Universidade de Vigo , Lagoas-Marcosende , 36310 , Vigo , Spain
| | - Olalla Nieto Faza
- Departamento de Química Orgánica , Universidade de Vigo , As Lagoas , 32004 , Ourense , Spain .
| | - Dean J Tantillo
- Department of Chemistry , University of California , One Shields Ave , Davis , CA 95616 , USA .
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16
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Pratihar S, Nicola Barbosa Muniz MC, Ma X, Borges I, Hase WL. Pronounced changes in atomistic mechanisms for the Cl - + CH 3I S N2 reaction with increasing collision energy. Phys Chem Chem Phys 2019; 21:2039-2045. [PMID: 30633280 DOI: 10.1039/c8cp06198j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In a previous direct dynamics simulation of the Cl- + CH3I → ClCH3 + I- SN2 reaction, predominantly indirect and direct reaction was found at collision energies Erel of 0.20 and 0.39 eV, respectively. For the work presented here, these simulations were extended by studying the reaction dynamics from Erel of 0.15 to 0.40 eV in 0.05 eV intervals. A transition from a predominantly indirect to direct reaction is found for Erel of 0.27-0.28 eV, a finding consistent with experiment. The simulation results corroborate the understanding that in experiments indirect reaction is characterized by small product translational energies and isotropic scattering, while direct reaction has higher translational energies and anisotropic scattering. The traditional statistical theoretical model for the Cl- + CH3I SN2 reaction assumes the Cl--CH3I pre-reaction complex (A) is formed, followed by barrier crossing, and then formation of the ClCH3-I- post-reaction complex (B). This mechanism is seen in the dynamics, but the complete atomistic dynamics are much more complex. Atomistic SN2 mechanisms contain A and B, but other dynamical events consisting of barrier recrossing (br) and the roundabout (Ra), in which the CH3-moiety rotates around the heavy I-atom, are also observed. The two most important mechanisms are only formation of A and Ra + A. The simulation results are compared with simulations and experiments for Cl- + CH3Cl, Cl- + CH3Br, F- + CH3I, and OH- + CH3I.
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Affiliation(s)
- Subha Pratihar
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, USA.
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17
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Olasz B, Czakó G. Uncovering the role of the stationary points in the dynamics of the F - + CH 3I reaction. Phys Chem Chem Phys 2019; 21:1578-1586. [PMID: 30620025 DOI: 10.1039/c8cp06207b] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe an analysis method which assigns geometries to stationary points along (quasi)classical trajectories. The method is applied to the F- + CH3I reaction, thereby uncovering the role of the minima and transition states in the dynamics of the SN2 inversion, SN2 retention via front-side attack and double inversion, induced inversion, and proton-transfer channels. Stationary-point probability distributions, stationary-point-specific trajectory orthogonal projections, root-mean-square distance distributions, transition probability matrices, and time evolutions of the stationary points reveal long-lived front-side (F-ICH3) and hydrogen-bonded (F-HCH2I) complexes in the entrance channel and significant post-reaction ion-dipole complex (FCH3I-) formation in the SN2 exit channel. Most of the proton-transfer stationary points (FHCH2I-) participate in all the reaction channels with larger distance deviations than the double-inversion transition state. Significant forward-backward transitions are observed between the minima and transition states indicating complex, indirect dynamics. The utility of distance and energy constraints is also investigated, thereby restricting the assignment into uniform configuration or energy ranges around the stationary points.
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Affiliation(s)
- Balázs Olasz
- 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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18
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Tasi DA, Fábián Z, Czakó G. Benchmark ab Initio Characterization of the Inversion and Retention Pathways of the OH– + CH3Y [Y = F, Cl, Br, I] SN2 Reactions. J Phys Chem A 2018; 122:5773-5780. [DOI: 10.1021/acs.jpca.8b04218] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Domonkos A. Tasi
- Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Zita Fábián
- Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Gábor Czakó
- 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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