Cope rearrangements in shapeshifting molecules re-examined by means of high-level CCSDT(Q) composite ab initio methods

Amir Karton

doi:10.1016/j.cplett.2020.138018

Cope rearrangements in shapeshifting molecules re-examined by means of high-level CCSDT(Q) composite ab initio methods

Amir Karton

School of Molecular Sciences

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Abstract

Benchmark reaction barrier heights for the degenerate Cope rearrangements in the highly fluxional bullvalene and semibullvalene hydrocarbon cages are obtained at the CCSDT(Q) level close to the one-particle basis set limit and include inner-shell, scalar-relativistic, and Born–Oppenheimer corrections. Our best theoretical CCSDT(Q) Gibbs free reaction barrier height for semibullvalene (ΔG₂₉₈^‡ = 27.9 kJ mol⁻¹) is in good agreement with the most recent experimental value of 25.9 kJ mol⁻¹. However, our CCSDT(Q) reaction barrier height for bullvalene (ΔG₂₉₈^‡ = 62.2 kJ mol⁻¹) indicates that the most recent gas-phase experimental value of 54.8 ± 0.8 should be revised upward.

Original language	English
Article number	138018
Journal	Chemical Physics Letters
Volume	759
DOIs	https://doi.org/10.1016/j.cplett.2020.138018
Publication status	Published - 16 Nov 2020

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10.1016/j.cplett.2020.138018

Karton, A. 2020 Cope rearrangements in shapeshifting molecules re-examined by means of high-level CCSDT(Q) composite ab inito methodsLicence: CC BY-NC-ND

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@article{e0620eb08fb84e278f9981fe4a52379f,

title = "Cope rearrangements in shapeshifting molecules re-examined by means of high-level CCSDT(Q) composite ab initio methods",

abstract = "Benchmark reaction barrier heights for the degenerate Cope rearrangements in the highly fluxional bullvalene and semibullvalene hydrocarbon cages are obtained at the CCSDT(Q) level close to the one-particle basis set limit and include inner-shell, scalar-relativistic, and Born–Oppenheimer corrections. Our best theoretical CCSDT(Q) Gibbs free reaction barrier height for semibullvalene (ΔG298‡ = 27.9 kJ mol−1) is in good agreement with the most recent experimental value of 25.9 kJ mol−1. However, our CCSDT(Q) reaction barrier height for bullvalene (ΔG298‡ = 62.2 kJ mol−1) indicates that the most recent gas-phase experimental value of 54.8 ± 0.8 should be revised upward.",

keywords = "Bullvalene, Semibullvalene, CCSD(T), CCSDT(Q), W4 theory, Shapeshifting molecules, Cope rearrangement",

author = "Amir Karton",

year = "2020",

month = nov,

day = "16",

doi = "10.1016/j.cplett.2020.138018",

language = "English",

volume = "759",

journal = "Chemical Physics Letters",

issn = "0009-2614",

publisher = "Pergamon",

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TY - JOUR

T1 - Cope rearrangements in shapeshifting molecules re-examined by means of high-level CCSDT(Q) composite ab initio methods

AU - Karton, Amir

PY - 2020/11/16

Y1 - 2020/11/16

N2 - Benchmark reaction barrier heights for the degenerate Cope rearrangements in the highly fluxional bullvalene and semibullvalene hydrocarbon cages are obtained at the CCSDT(Q) level close to the one-particle basis set limit and include inner-shell, scalar-relativistic, and Born–Oppenheimer corrections. Our best theoretical CCSDT(Q) Gibbs free reaction barrier height for semibullvalene (ΔG298‡ = 27.9 kJ mol−1) is in good agreement with the most recent experimental value of 25.9 kJ mol−1. However, our CCSDT(Q) reaction barrier height for bullvalene (ΔG298‡ = 62.2 kJ mol−1) indicates that the most recent gas-phase experimental value of 54.8 ± 0.8 should be revised upward.

AB - Benchmark reaction barrier heights for the degenerate Cope rearrangements in the highly fluxional bullvalene and semibullvalene hydrocarbon cages are obtained at the CCSDT(Q) level close to the one-particle basis set limit and include inner-shell, scalar-relativistic, and Born–Oppenheimer corrections. Our best theoretical CCSDT(Q) Gibbs free reaction barrier height for semibullvalene (ΔG298‡ = 27.9 kJ mol−1) is in good agreement with the most recent experimental value of 25.9 kJ mol−1. However, our CCSDT(Q) reaction barrier height for bullvalene (ΔG298‡ = 62.2 kJ mol−1) indicates that the most recent gas-phase experimental value of 54.8 ± 0.8 should be revised upward.

KW - Bullvalene

KW - Semibullvalene

KW - CCSD(T)

KW - CCSDT(Q)

KW - W4 theory

KW - Shapeshifting molecules

KW - Cope rearrangement

UR - http://www.scopus.com/inward/record.url?scp=85092053156&partnerID=8YFLogxK

U2 - 10.1016/j.cplett.2020.138018

DO - 10.1016/j.cplett.2020.138018

M3 - Article

AN - SCOPUS:85092053156

SN - 0009-2614

VL - 759

JO - Chemical Physics Letters

JF - Chemical Physics Letters

M1 - 138018

ER -

Cope rearrangements in shapeshifting molecules re-examined by means of high-level CCSDT(Q) composite ab initio methods

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High-level quantum chemistry: From theory to applications

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Cope rearrangements in shapeshifting molecules re-examined by means of high-level CCSDT(Q) composite ab initio methods

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High-level quantum chemistry: From theory to applications

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