Heterogeneously substituted radicals and carbenes: Photoelectron imaging of the FC(H)CN-and FCCN- anions

Andrew R. Dixon, Dmitry Khuseynov, Andrei M Sanov

Research output: Contribution to journalArticle

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Abstract

This work represents the next step in the studies of heterogeneous substitution effects in cyanohalo radicals and carbenes. Negative-ion photoelectron imaging was used to investigate the substituted radical and carbene derivatives of fluoroacetonitrile. We report a closed-shell singlet ground state for cyanofluorocarbene, FCCN, with a directly measured adiabatic electron affinity EA = 2.081 ± 0.002 eV and a singlet-triplet gap of ΔES-T = 0.42 ± 0.04 eV, estimated through a combination of experimental and theoretical results. The open-shell singlet 1A″ state was also observed experimentally. The cyanofluoromethyl radical, FC(H)CN, was similarly estimated to have an EA of 1.53 ± 0.08 eV. This value was used to estimate the C-H bond dissociation energy (BDE) of fluoroacetonitrile, DH298 = 90.7 ± 2.8 kcal mol-1. The results are discussed in comparison with results for other fluoro and cyano-substituted radicals and carbenes, and in light of our recent work on the radical and carbene derivatives of chloroacetonitrile. The estimated ΔES-T of FCCN agrees well with the general trend of similar carbenes. We also find that, similar to chloroacetonitrile, the low C-H BDE of fluoroaceotnitrile indicates a synergistic stabilization of the corresponding radical by a π donor (halogen) and π acceptor (CN).

Original languageEnglish (US)
Pages (from-to)8533-8541
Number of pages9
JournalJournal of Physical Chemistry A
Volume118
Issue number37
DOIs
StatePublished - Sep 18 2014

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carbenes
Photoelectrons
Anions
photoelectrons
anions
Imaging techniques
Derivatives
Electron affinity
Halogens
dissociation
Ground state
electron affinity
Substitution reactions
Negative ions
negative ions
halogens
Stabilization
carbene
stabilization
substitutes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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Heterogeneously substituted radicals and carbenes : Photoelectron imaging of the FC(H)CN-and FCCN- anions. / Dixon, Andrew R.; Khuseynov, Dmitry; Sanov, Andrei M.

In: Journal of Physical Chemistry A, Vol. 118, No. 37, 18.09.2014, p. 8533-8541.

Research output: Contribution to journalArticle

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