The F-+CH3I → FCH3 +I- entrance channel potential energy surface Comparison of electronic structure methods

Rui Sun; Jing Xie; Jiaxu Zhang; William L. Hase

doi:10.1016/j.ijms.2014.04.006

The F^-+CH₃I → FCH₃ +I^- entrance channel potential energy surface Comparison of electronic structure methods

Rui Sun, Jing Xie, Jiaxu Zhang, William L. Hase

Chemistry (Twin Cities)

Research output: Contribution to journal › Article › peer-review

19 Scopus citations

Abstract

The potential energy surface (PES) of the F^- + CH₃I → FCH₃ +I^- S_n2 nucleophilic substitution reaction has been studied previously using MP2 and DFT levels of theory (J. Phys. Chem. A 2010,114,9635-9643). This work indicated that DFT gives a better representation of the PES which has only an hydrogen-bonded entrance channel reaction path, with a hydrogen-bonded transition state [F··HCH₂··I]^- connecting the hydrogen-bonded pre-reaction complex F^-··· HCH₂I and C_3v post-reaction complex FCH₃··· I^-. For the work presented here, CCSD(T) with three different basis set and two effective core potentials (i.e. PP/d, PP/t and ECP/d) was employed to investigate stationary point properties for this reaction. Besides the hydrogen-bonded entrance channel stationary points, CCSD(T) also predicts a traditional C_3v transition state [F··CH₃·· I]^- connecting a C_3v pre-reaction complex F^-·· CH₃I with the C_3v post-reaction complex FCH₃ · · ·I^-. Though CCSD(T) gives a CH₃F···I^- binding energy and CH₃ F and CH₃I geometries in almost exact agreement with experiment, it gives a heat of reaction ∼20 kJ/mol less exothermic than experiment. The MP2 PES for this reaction, determined in the previous study, is very similar to the CCSD(T), but obtained with a much smaller computational cost. Direct dynamics simulations for the F^- + CH₃I→ FCH₃ +I^- reaction are feasible with MP2.

Original language	English (US)
Pages (from-to)	222-227
Number of pages	6
Journal	International Journal of Mass Spectrometry
Volume	377
Issue number	1
DOIs	https://doi.org/10.1016/j.ijms.2014.04.006
State	Published - 2015

Bibliographical note

Funding Information:
This material is based upon work supported by the Robert A. Welch Foundation under grant D-0005 . The authors acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing HPC resources that have contributed to the research results reported within this paper (URL: http://www.tacc.utexas.edu ). Jiaxu Zhang acknowledges financial support from the Institute of Chemistry, Chinese Academy of Sciences ( No. CMS-PY-201316 ). Support was also provided by the High-Performance Computing Center (HPCC) at Texas Tech University (TTU) , under the direction of Philip W. Smith, and the TTU Department of Chemistry & Biochemistry cluster Robinson, whose purchase was funded by the National Science Foundation under the CRIF-MU Grant No. CHE-0840493 . The authors also wish to thank Branko Ruscic for helpful comments.

Publisher Copyright:
© 2014 Elsevier B.V. All rights reserved.

Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.

Keywords

Ion
Molecular dynamics simulation
Nucleophilic substitution reaction

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title = "The F-+CH3I → FCH3 +I- entrance channel potential energy surface Comparison of electronic structure methods",

abstract = "The potential energy surface (PES) of the F- + CH3I → FCH3 +I- Sn2 nucleophilic substitution reaction has been studied previously using MP2 and DFT levels of theory (J. Phys. Chem. A 2010,114,9635-9643). This work indicated that DFT gives a better representation of the PES which has only an hydrogen-bonded entrance channel reaction path, with a hydrogen-bonded transition state [F··HCH2··I]- connecting the hydrogen-bonded pre-reaction complex F-··· HCH2I and C3v post-reaction complex FCH3··· I-. For the work presented here, CCSD(T) with three different basis set and two effective core potentials (i.e. PP/d, PP/t and ECP/d) was employed to investigate stationary point properties for this reaction. Besides the hydrogen-bonded entrance channel stationary points, CCSD(T) also predicts a traditional C3v transition state [F··CH3·· I]- connecting a C3v pre-reaction complex F-·· CH3I with the C3v post-reaction complex FCH3 · · ·I-. Though CCSD(T) gives a CH3F···I- binding energy and CH3 F and CH3I geometries in almost exact agreement with experiment, it gives a heat of reaction ∼20 kJ/mol less exothermic than experiment. The MP2 PES for this reaction, determined in the previous study, is very similar to the CCSD(T), but obtained with a much smaller computational cost. Direct dynamics simulations for the F- + CH3I→ FCH3 +I- reaction are feasible with MP2.",

keywords = "Ion, Molecular dynamics simulation, Nucleophilic substitution reaction",

author = "Rui Sun and Jing Xie and Jiaxu Zhang and Hase, {William L.}",

note = "Funding Information: This material is based upon work supported by the Robert A. Welch Foundation under grant D-0005 . The authors acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing HPC resources that have contributed to the research results reported within this paper (URL: http://www.tacc.utexas.edu ). Jiaxu Zhang acknowledges financial support from the Institute of Chemistry, Chinese Academy of Sciences ( No. CMS-PY-201316 ). Support was also provided by the High-Performance Computing Center (HPCC) at Texas Tech University (TTU) , under the direction of Philip W. Smith, and the TTU Department of Chemistry & Biochemistry cluster Robinson, whose purchase was funded by the National Science Foundation under the CRIF-MU Grant No. CHE-0840493 . The authors also wish to thank Branko Ruscic for helpful comments. Publisher Copyright: {\textcopyright} 2014 Elsevier B.V. All rights reserved. Copyright: Copyright 2017 Elsevier B.V., All rights reserved.",

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T1 - The F-+CH3I → FCH3 +I- entrance channel potential energy surface Comparison of electronic structure methods

AU - Sun, Rui

AU - Xie, Jing

AU - Zhang, Jiaxu

AU - Hase, William L.

N1 - Funding Information: This material is based upon work supported by the Robert A. Welch Foundation under grant D-0005 . The authors acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing HPC resources that have contributed to the research results reported within this paper (URL: http://www.tacc.utexas.edu ). Jiaxu Zhang acknowledges financial support from the Institute of Chemistry, Chinese Academy of Sciences ( No. CMS-PY-201316 ). Support was also provided by the High-Performance Computing Center (HPCC) at Texas Tech University (TTU) , under the direction of Philip W. Smith, and the TTU Department of Chemistry & Biochemistry cluster Robinson, whose purchase was funded by the National Science Foundation under the CRIF-MU Grant No. CHE-0840493 . The authors also wish to thank Branko Ruscic for helpful comments. Publisher Copyright: © 2014 Elsevier B.V. All rights reserved. Copyright: Copyright 2017 Elsevier B.V., All rights reserved.

PY - 2015

Y1 - 2015

N2 - The potential energy surface (PES) of the F- + CH3I → FCH3 +I- Sn2 nucleophilic substitution reaction has been studied previously using MP2 and DFT levels of theory (J. Phys. Chem. A 2010,114,9635-9643). This work indicated that DFT gives a better representation of the PES which has only an hydrogen-bonded entrance channel reaction path, with a hydrogen-bonded transition state [F··HCH2··I]- connecting the hydrogen-bonded pre-reaction complex F-··· HCH2I and C3v post-reaction complex FCH3··· I-. For the work presented here, CCSD(T) with three different basis set and two effective core potentials (i.e. PP/d, PP/t and ECP/d) was employed to investigate stationary point properties for this reaction. Besides the hydrogen-bonded entrance channel stationary points, CCSD(T) also predicts a traditional C3v transition state [F··CH3·· I]- connecting a C3v pre-reaction complex F-·· CH3I with the C3v post-reaction complex FCH3 · · ·I-. Though CCSD(T) gives a CH3F···I- binding energy and CH3 F and CH3I geometries in almost exact agreement with experiment, it gives a heat of reaction ∼20 kJ/mol less exothermic than experiment. The MP2 PES for this reaction, determined in the previous study, is very similar to the CCSD(T), but obtained with a much smaller computational cost. Direct dynamics simulations for the F- + CH3I→ FCH3 +I- reaction are feasible with MP2.

AB - The potential energy surface (PES) of the F- + CH3I → FCH3 +I- Sn2 nucleophilic substitution reaction has been studied previously using MP2 and DFT levels of theory (J. Phys. Chem. A 2010,114,9635-9643). This work indicated that DFT gives a better representation of the PES which has only an hydrogen-bonded entrance channel reaction path, with a hydrogen-bonded transition state [F··HCH2··I]- connecting the hydrogen-bonded pre-reaction complex F-··· HCH2I and C3v post-reaction complex FCH3··· I-. For the work presented here, CCSD(T) with three different basis set and two effective core potentials (i.e. PP/d, PP/t and ECP/d) was employed to investigate stationary point properties for this reaction. Besides the hydrogen-bonded entrance channel stationary points, CCSD(T) also predicts a traditional C3v transition state [F··CH3·· I]- connecting a C3v pre-reaction complex F-·· CH3I with the C3v post-reaction complex FCH3 · · ·I-. Though CCSD(T) gives a CH3F···I- binding energy and CH3 F and CH3I geometries in almost exact agreement with experiment, it gives a heat of reaction ∼20 kJ/mol less exothermic than experiment. The MP2 PES for this reaction, determined in the previous study, is very similar to the CCSD(T), but obtained with a much smaller computational cost. Direct dynamics simulations for the F- + CH3I→ FCH3 +I- reaction are feasible with MP2.

KW - Ion

KW - Molecular dynamics simulation

KW - Nucleophilic substitution reaction

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