Singlet/Triplet State Anti/Aromaticity of CyclopentadienylCation: Sensitivity to Substituent Effect
Open accessAbstract
It is well known that singlet state aromaticity is quite insensitive to substituent effects, in the case of monosubstitution. In this work, we use density functional theory (DFT) calculations to examine the sensitivity of triplet state aromaticity to substituent effects. For this purpose, we chose the singlet state antiaromatic cyclopentadienyl cation, antiaromaticity of which reverses to triplet state aromaticity, conforming to Baird’s rule. The extent of (anti)aromaticity was evaluated by using structural (HOMA), magnetic (NICS), energetic (ISE), and electronic (EDDBp) criteria. We find that the extent of triplet state aromaticity of monosubstituted cyclopentadienyl cations is weaker than the singlet state aromaticity of benzene and is, thus, slightly more sensitive to substituent effects. As an addition to the existing literature data, we also discuss substituent effects on singlet state antiaromaticity of cyclopentadienyl cation.
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The triplet state aromaticity of cyclopentadienyl cations is more sensitive to substituent effects than the ground state aromaticity of benzene.
“Similar conclusions were obtained by studying the sensitivity of the triplet state aromaticity of cyclopentadienyl cations to sub-stituent effects, which is more sensitive than the ground state aromaticity of benzene [206].”
From Aromaticity and Antiaromaticity: How to Define Them (2025) · cites this paper as [206]
Cites
Which NICS Aromaticity Index for Planar π Rings Is Best?
Fallah-Bagher-Shaidaei, H., Wannere, C. S., Corminboeuf, C., Puchta, R., & Schleyer, P. V. R. (2006) · Organic Letters · doi:10.1021/ol0529546 · Cited by 1,257 · see citing works
Baird, N. C. (1972) · Journal of the American Chemical Society · doi:10.1021/ja00769a025 · Cited by 680 · see citing works
Rosenberg, M., Dahlstrand, C., Kilså, K., & Ottosson, H. (2014) · Chemical Reviews · doi:10.1021/cr300471v · Cited by 505 · see citing works
Szczepanik, D. W., Solà, M., Andrzejak, M., Pawełek, B., Dominikowska, J., Kukułka, M., Dyduch, K., Krygowski, T. M., & Szatylowicz, H. (2017) · Journal of Computational Chemistry · doi:10.1002/jcc.24805 · Cited by 107 · cited 1× · see citing works
“It was reported recently that the local character of the exchange–correlation functional, such as B3LYP, may lead to an inconsistent picture of aromaticity due to the overestimation of electron delocalization [91].”
BackgroundKaradakov, P. B., Hearnshaw, P., & Horner, K. E. (2016) · The Journal of Organic Chemistry · doi:10.1021/acs.joc.6b02460 · Cited by 96 · see citing works
Evaluation of Triplet Aromaticity by the Indene–Isoindene Isomerization Stabilization Energy Method
An, K., & Zhu, J. (2014) · European Journal of Organic Chemistry · doi:10.1002/ejoc.201301810 · Cited by 57 · see citing works
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Aromaticity and Antiaromaticity: How to Define Them
Baranac-Stojanović, M. (2025) · Chemistry · doi:10.3390/chemistry7040127 · Cited by 14 · see citing works
Self-citation
- Authors
- Stojanović, M., Aleksić, J., & Baranac-Stojanović, M.
- Affiliations
- University of Belgrade (RS)
- Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, P.O. Box 158, 11000 Belgrade, Serbia
- ORCID
- Stojanović, Milovan
- Venue
- Chemistry
- Publisher
- MDPI AG
- Published
- 2021-07-21
- Volume
- 3
- Issue
- 3
- Pages
- 765-782
- ISSN
- 2624-8549 (ISSN-L)
- OpenAlex
- W3186858347
- Cited by
- 13
- References
- 6
- Citations by year
- 2026: 2 · 2025: 3 · 2024: 2 · 2023: 3 · 2022: 2 · 2021: 1
- FWCI
- 0.79
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- Chemistry (publishedVersion, cc-by)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Funders
- Ministarstvo Prosvete, Nauke i Tehnološkog Razvoja (451-03-68/2020-14/200168)
- Topics
- Physical Sciences › Chemistry › Organic Chemistry › Synthesis and Properties of Aromatic Compounds
- Physical Sciences › Chemistry › Organic Chemistry › Organic Chemistry Cycloaddition Reactions
- Physical Sciences › Chemistry › Organic Chemistry › Cyclization and Aryne Chemistry
- Keywords
- cyclopentadienyl cations, substituent effects, Baird's rule, HOMA, NICS, Ise, aromaticity descriptors
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