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Manikandan P, Zhang J, Hase WL. Chemical dynamics simulations of X- + CH3Y → XCH3 + Y- gas-phase S(N)2 nucleophilic substitution reactions. Nonstatistical dynamics and nontraditional reaction mechanisms. J Phys Chem A 2012; 116:3061-80. [PMID: 22313150 DOI: 10.1021/jp211387c] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Extensive classical chemical dynamics simulations of gas-phase X(-) + CH(3)Y → XCH(3) + Y(-) S(N)2 nucleophilic substitution reactions are reviewed and discussed and compared with experimental measurements and predictions of theoretical models. The primary emphasis is on reactions for which X and Y are halogen atoms. Both reactions with the traditional potential energy surface (PES), which include pre- and postreaction potential energy minima and a central barrier, and reactions with nontraditional PESs are considered. These S(N)2 reactions exhibit important nonstatistical atomic-level dynamics. The X(-) + CH(3)Y → X(-)---CH(3)Y association rate constant is less than the capture model as a result of inefficient energy transfer from X(-)+ CH(3)Y relative translation to CH(3)Y rotation and vibration. There is weak coupling between the low-frequency intermolecular modes of the X(-)---CH(3)Y complex and higher frequency CH(3)Y intramolecular modes, resulting in non-RRKM kinetics for X(-)---CH(3)Y unimolecular decomposition. Recrossings of the [X--CH(3)--Y](-) central barrier is important. As a result of the above dynamics, the relative translational energy and temperature dependencies of the S(N)2 rate constants are not accurately given by statistical theory. The nonstatistical dynamics results in nonstatistical partitioning of the available energy to XCH(3) +Y(-) reaction products. Besides the indirect, complex forming atomic-level mechanism for the S(N)2 reaction, direct mechanisms promoted by X(-) + CH(3)Y relative translational or CH(3)Y vibrational excitation are possible, e.g., the roundabout mechanism.
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Affiliation(s)
- Paranjothy Manikandan
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, USA
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Fernandez AI, Viggiano AA, Troe J. Two-Channel Dissociation of Chemically and Thermally Activated n-Butylbenzene Cations (C10H14+). J Phys Chem A 2006; 110:8467-76. [PMID: 16821830 DOI: 10.1021/jp056846c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The charge-transfer reaction O(2)(+) + n-butylbenzene (C(10)H(14)) --> O(2) + C(10)H(14)(+) was studied in a turbulent ion flow tube at temperatures between 423 and 548 K and pressures between 15 and 250 Torr in the buffer gases He and N(2). Under chemical activation conditions stabilization vs dissociation ratios S/D of vibrationally highly excited C(10)H(14)(+)* as well as branching ratios of the fragments C(7)H(7)(+) (m/z = 91) vs C(7)H(8)(+) (m/z = 92) of the dissociation of C(10)H(14)(+)* were measured. Under thermal activation conditions, the rate constant of the dominating dissociation channel 92 was measured at 498 and 523 K. Employing information on the specific rate constants k(E) of the two channels 91 and 92 and on collisional energy transfer rates from the literature, the measured S/D curves and branching ratios 91/92 could be modeled well. It is demonstrated that the charge transfer occurs approximately equally through resonant transfer and complex-forming transfer. The thermal dissociation experiments provide a high precision value of the energy barrier for the channel 92, being 1.14 (+/-0.02) eV.
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Affiliation(s)
- Abel I Fernandez
- Air Force Research Laboratory, Space Vehicles Directorate, 29 Randolph Rd., Hanscom AFB, Massachusetts 01731-3010, USA
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Ren J, Brauman JI. Energy Deposition in SN2 Reaction Products and Kinetic Energy Effects on Reactivity. J Phys Chem A 2002. [DOI: 10.1021/jp0141070] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jianhua Ren
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - John I. Brauman
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
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Craig SL, Zhong M, Brauman JI. Translational Energy Dependence and Potential Energy Surfaces of Gas Phase SN2 and Addition−Elimination Reactions. J Am Chem Soc 1999. [DOI: 10.1021/ja990556q] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Stephen L. Craig
- Contribution from the Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - Meili Zhong
- Contribution from the Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - John I. Brauman
- Contribution from the Department of Chemistry, Stanford University, Stanford, California 94305-5080
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Su T, Wang H, Hase WL. Trajectory Studies of SN2 Nucleophilic Substitution. 7. F- + CH3Cl → FCH3 + Cl-. J Phys Chem A 1998. [DOI: 10.1021/jp982386u] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Timothy Su
- Department of Chemistry, University of Massachusetts, N. Dartmouth, Massachusetts 02747-2300
| | - Haobin Wang
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202-3489
| | - William L. Hase
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202-3489
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Craig SL, Zhong M, Brauman JI. Nonstatistical Reactivity in a Vibrationally Excited SN2 Intermediate. J Am Chem Soc 1998. [DOI: 10.1021/ja982253m] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Stephen L. Craig
- Department of Chemistry, Stanford University Stanford, California 94305-5080
| | - Meili Zhong
- Department of Chemistry, Stanford University Stanford, California 94305-5080
| | - John I. Brauman
- Department of Chemistry, Stanford University Stanford, California 94305-5080
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Chabinyc ML, Craig SL, Regan CK, Brauman JI. Gas-phase ionic reactions: dynamics and mechanism of nucleophilic displacements. Science 1998; 279:1882-6. [PMID: 9506930 DOI: 10.1126/science.279.5358.1882] [Citation(s) in RCA: 245] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Nucleophilic displacement reactions (the SN2 reaction) of ions in the gas phase are a prototypical reaction system that allows a study of dynamics, mechanisms, and structure-energy relations. This article reviews aspects of the kinetics (especially the applicability of statistical reaction rate theory), the relation of structure and reactivity, and the effects of small numbers of solvent molecules on the reaction and compares the behavior of the ionic reaction in the gas phase with that in solution.
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Affiliation(s)
- ML Chabinyc
- M. L. Chabinyc, C. K. Regan, and J. I. Brauman are in the Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA. S. L. Craig is in the Central Research and Development Department, E. I. DuPont de Nemours and Company, Incorporated
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Craig SL, Brauman JI. Phase-Shifting Acceleration of Ions in an Ion Cyclotron Resonance Spectrometer: Kinetic Energy Distribution and Reaction Dynamics. J Phys Chem A 1997. [DOI: 10.1021/jp970602d] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Stephen L. Craig
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - John I. Brauman
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
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Affiliation(s)
- Haobin Wang
- Contribution from the Department of Chemistry, Wayne State University, Detroit, Michigan 48202
| | - William L. Hase
- Contribution from the Department of Chemistry, Wayne State University, Detroit, Michigan 48202
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Dienes T, Pastor SJ, Schürch S, Scott JR, Yao J, Cui S, Wilkins CL. Fourier transform mass spectrometry-advancing years (1992-mid. 1996). MASS SPECTROMETRY REVIEWS 1996; 15:163-211. [PMID: 27082513 DOI: 10.1002/(sici)1098-2787(1996)15:3<163::aid-mas2>3.0.co;2-g] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/1996] [Revised: 10/18/1996] [Accepted: 10/22/1996] [Indexed: 06/05/2023]
Abstract
This article is one of a series of Fourier transform mass spectrometry (FTMS) reviews that has appeared in this journal at ca. 3-4 year intervals. A comprehensive review of the recent theoretical developments, instrumental developments, electrospray ionization (ESI), and MALDI is given. Ion dissociation techniques are also discussed because of their contributions to gaining insight into chemical structure. Special sections have been devoted to discussing the emerging fields of surface analysis, polymer analysis, Buckminsterfullerenes (buckyballs), and hydrogen/deuterium exchange studies. This review, although not all-inclusive, is intended to be a starting point for those wishing to learn more about the current status of FTMS, and also as a representative cross-section of the literature for those familiar with the technique. © 1997 John Wiley & Sons, Inc.
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Affiliation(s)
- T Dienes
- Department of Chemistry, University of California-Riverside, Riverside, California 92521
| | - S J Pastor
- Department of Chemistry, University of California-Riverside, Riverside, California 92521
| | - S Schürch
- Department of Chemistry, University of California-Riverside, Riverside, California 92521
| | - J R Scott
- Department of Chemistry, University of California-Riverside, Riverside, California 92521
| | - J Yao
- Department of Chemistry, University of California-Riverside, Riverside, California 92521
| | - S Cui
- Department of Chemistry, University of California-Riverside, Riverside, California 92521
| | - C L Wilkins
- Department of Chemistry, University of California-Riverside, Riverside, California 92521
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Hase WL, Cho YJ. Trajectory studies of SN2 nucleophilic substitution. III. Dynamical stereochemistry and energy transfer pathways for the Cl−+CH3Cl association and direct substitution reactions. J Chem Phys 1993. [DOI: 10.1063/1.464470] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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