Computational study on the stability of imidazol-2-ylidenes and imidazolin-2-ylidenes

Mu Jeng Cheng, Ching-Han Hu

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

The dimerization reactions of 12 cyclic diaminocarbenes have been studied using density functional theory (DFT). The activation energies (Ea) and reaction energies (ΔE) for the dimerizations of imidazol-2-ylidenes are larger than those of imidazolin-2-ylidenes. It was observed that Ea of dimerization is approximately proportional to the singlet-triplet energy separation (ΔES-T), aromatic stabilization energy (ASE), and ΔE of the carbene. Excellent linear correlation is seen between Ea and ASE. Contrary to previous suggestions, we found that 4,5-dichloro substitutions decrease the stability of imidazol(in)-2-ylidenes. Steric effects on Ea occur noticeably as isopropyl (i-Pr) substitutions are introduced to the carbenes.

Original languageEnglish
Pages (from-to)477-482
Number of pages6
JournalChemical Physics Letters
Volume349
Issue number5-6
DOIs
Publication statusPublished - 2001 Dec 7

Fingerprint

Dimerization
imidazoles
dimerization
carbenes
Substitution reactions
Stabilization
stabilization
substitutes
Density functional theory
energy
Activation energy
Chemical activation
suggestion
activation energy
density functional theory
carbene

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

@article{d07511613fdf45eeb4e75865c233d021,
title = "Computational study on the stability of imidazol-2-ylidenes and imidazolin-2-ylidenes",
abstract = "The dimerization reactions of 12 cyclic diaminocarbenes have been studied using density functional theory (DFT). The activation energies (Ea) and reaction energies (ΔE) for the dimerizations of imidazol-2-ylidenes are larger than those of imidazolin-2-ylidenes. It was observed that Ea of dimerization is approximately proportional to the singlet-triplet energy separation (ΔES-T), aromatic stabilization energy (ASE), and ΔE of the carbene. Excellent linear correlation is seen between Ea and ASE. Contrary to previous suggestions, we found that 4,5-dichloro substitutions decrease the stability of imidazol(in)-2-ylidenes. Steric effects on Ea occur noticeably as isopropyl (i-Pr) substitutions are introduced to the carbenes.",
author = "Cheng, {Mu Jeng} and Ching-Han Hu",
year = "2001",
month = "12",
day = "7",
doi = "10.1016/S0009-2614(01)01234-9",
language = "English",
volume = "349",
pages = "477--482",
journal = "Chemical Physics Letters",
issn = "0009-2614",
publisher = "Elsevier",
number = "5-6",

}

Computational study on the stability of imidazol-2-ylidenes and imidazolin-2-ylidenes. / Cheng, Mu Jeng; Hu, Ching-Han.

In: Chemical Physics Letters, Vol. 349, No. 5-6, 07.12.2001, p. 477-482.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Computational study on the stability of imidazol-2-ylidenes and imidazolin-2-ylidenes

AU - Cheng, Mu Jeng

AU - Hu, Ching-Han

PY - 2001/12/7

Y1 - 2001/12/7

N2 - The dimerization reactions of 12 cyclic diaminocarbenes have been studied using density functional theory (DFT). The activation energies (Ea) and reaction energies (ΔE) for the dimerizations of imidazol-2-ylidenes are larger than those of imidazolin-2-ylidenes. It was observed that Ea of dimerization is approximately proportional to the singlet-triplet energy separation (ΔES-T), aromatic stabilization energy (ASE), and ΔE of the carbene. Excellent linear correlation is seen between Ea and ASE. Contrary to previous suggestions, we found that 4,5-dichloro substitutions decrease the stability of imidazol(in)-2-ylidenes. Steric effects on Ea occur noticeably as isopropyl (i-Pr) substitutions are introduced to the carbenes.

AB - The dimerization reactions of 12 cyclic diaminocarbenes have been studied using density functional theory (DFT). The activation energies (Ea) and reaction energies (ΔE) for the dimerizations of imidazol-2-ylidenes are larger than those of imidazolin-2-ylidenes. It was observed that Ea of dimerization is approximately proportional to the singlet-triplet energy separation (ΔES-T), aromatic stabilization energy (ASE), and ΔE of the carbene. Excellent linear correlation is seen between Ea and ASE. Contrary to previous suggestions, we found that 4,5-dichloro substitutions decrease the stability of imidazol(in)-2-ylidenes. Steric effects on Ea occur noticeably as isopropyl (i-Pr) substitutions are introduced to the carbenes.

UR - http://www.scopus.com/inward/record.url?scp=0041418106&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0041418106&partnerID=8YFLogxK

U2 - 10.1016/S0009-2614(01)01234-9

DO - 10.1016/S0009-2614(01)01234-9

M3 - Article

AN - SCOPUS:0041418106

VL - 349

SP - 477

EP - 482

JO - Chemical Physics Letters

JF - Chemical Physics Letters

SN - 0009-2614

IS - 5-6

ER -