Research on Chemical Intermediates

, Volume 43, Issue 3, pp 1575–1590 | Cite as

Understanding the kinetics and mechanism of thermal cheletropic elimination of N2 from (2,5-dihydro-1H-pyrrol-1-ium-1-ylidene) amide using RRKM and ELF theories

  • Ehsan Zahedi
  • Majid Mozaffari
  • Farzaneh Shahsavar
  • Abolfazl Shiroudi
  • Michael S. Deleuze


The cheletropic elimination process of N2 from (2,5-dihydro-1H-pyrrol-1-ium-1-ylidene) amide (C4H6N2) has been studied computationally using density functional theory, along with the M06-2X/aug-cc-pVTZ level of theory. The calculated energy profile has been supplemented with calculations of kinetic rate constants using transition state theory (TST) and statistical Rice–Ramsperger–Kassel–Marcus (RRKM) theory. This elimination process takes place spontaneously with an activation energy around 33 kJ/mol. Pressure dependence of the rate constants revealed that the TST approximation breaks down and fall-off expression is necessary for the kinetic modeling. At temperatures ranging from 240 to 360 K and atmospheric pressure, the unimolecular rate constant is evaluated from RRKM theory as \(k_{{(240 - 360\,{\text{K}})}}^{{1.0{\text{atm}}}} = 1.0249 \times 10^{12} \times {\text{e}}^{{ - \frac{{33.11\;{\text{kJ}}/{\text{mol}}}}{RT}}} \,{\text{s}}^{ - 1}\). Bonding changes along the reaction coordinate have been studied using bonding evolution theory. Electron localization function topological analysis reveals that the cheletropic elimination is characterized topologically by four successive structural stability domains (SSDs). Breaking of C–N bonds (Rx = 0.1992 amu1/2 Bohr) and the other selected points separating the SSDs along the reaction coordinate occur in the vicinity of the transition state.


Cheletropic elimination DFT TST RRKM theory BET ELF 



The authors thank anonymous referees for highly relevant comments. E. Zahedi expresses his gratitude to the Islamic Azad University, Shahrood Branch.

Supplementary material

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Supplementary material 1 (DOCX 2320 kb)


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Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  • Ehsan Zahedi
    • 1
  • Majid Mozaffari
    • 1
  • Farzaneh Shahsavar
    • 1
  • Abolfazl Shiroudi
    • 2
  • Michael S. Deleuze
    • 3
  1. 1.Chemistry Department, Shahrood BranchIslamic Azad UniversityShahroodIran
  2. 2.Young Researchers and Elite Club, East Tehran BranchIslamic Azad UniversityTehranIran
  3. 3.Center of Molecular and Materials ModellingHasselt UniversityDiepenbeekBelgium

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