On the factors that control the reactivity of meta-benzynes

Jinshan Gao, Bartłomiej J. Jankiewicz, Jennifer Reece, Huaming Sheng, Christopher J. Cramer, John J. Nash, Hilkka I. Kenttämaa

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

The reactivities of eleven 3,5-didehydropyridinium and six 2,4-didehydropyridinium cations toward cyclohexane were examined in the gas phase by using Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry as well as high-level quantum chemical calculations. The results unequivocally demonstrate that the reactivity of meta-benzyne analogs can be "tuned" from more radical-like to less radical-like by changing the type and position of substituents. For example, σ-acceptor substituents at the 4-position and π-donor substituents at the 2-position in 3,5-didehydropyridinium cations partially decouple the biradical electrons, which results in lower energy transition states, and faster radical reactions. In contrast, σ-acceptors at the 2-position and π-donors at the 4-position in 3,5-didehydropyridinium cations cause stronger coupling between the biradical electrons, which results in lower radical reactivity. Three main factors are found to control the reactivity of these biradicals: (1) the energy required to distort the minimum energy dehydrocarbon atom separation to the separation of the transition state, (2) the S-T splitting at the separation of the transition state, and (3) the electron affinity at the separation of the transition state. This journal is

Original languageEnglish
Pages (from-to)2205-2215
Number of pages11
JournalChemical Science
Volume5
Issue number6
DOIs
StatePublished - Jun 2014

    Fingerprint

Cite this

Gao, J., Jankiewicz, B. J., Reece, J., Sheng, H., Cramer, C. J., Nash, J. J., & Kenttämaa, H. I. (2014). On the factors that control the reactivity of meta-benzynes. Chemical Science, 5(6), 2205-2215. https://doi.org/10.1039/c4sc00194j