An ESR study of the acetaldehyde radical cation in freon matrices: Evidence for halogen superhyperfine interaction

Stabilisation and reactions of aliphatic radical cations produced by fast electron irradiation in solid argon matrices

“…The g max value close to 2.007 is typical for oxygen-centered carbonyl radical cations. 1,5,[20][21][22][23] The g tensor is very similar to that reported in a neon matrix. 5 Meanwhile, the hyperfine coupling constant for the aldehydic proton (A iso ¼ 13.53 mT) is definitely larger than the value found in neon (12.86 mT 5 ) and close to that observed in a CFCl 3 matrix (13.6-13.7 mT 5,22 ).…”

“…Acetone radical cation has been characterized previously in halocarbon matrices. [19][20][21] This species exhibits a noticeable g anisotropy, whereas the hyperfine coupling to methyl protons is too small to be resolved, which results in an asymmetrical singlet EPR signal. Such a signal is clearly observed in the EPR spectrum recorded after irradiation of the deposited mixture argon/ Freon-11/acetone (Fig.…”

“…The EPR spectra of the acetaldehyde radical cation have been reported in both freonic and neon matrices. 5,[20][21][22][23][24] This species yields a characteristic asymmetrical doublet signal due to large hyperfine coupling to an aldehydic proton (isotropic constant of ca. 13 mT) and pronounced g and a anisotropy (especially, in neon).…”

Diketone Radical Cations: Ketonic and Enolic Forms As Revealed by Matrix EPR Studies and DFT Calculations

“…The radical cations of simple aliphatic ketones are characterized by n σ -type SOMO localized at the carbonyl oxygen atom. 10,11 We are unaware of any experimental or theoretical works on diketone radical cations. In addition to general modeling, an interesting aspect is concerned with the wellknown effect of keto-enolic tautomerism, which makes it possible to characterize both ketonic and enolic forms of radical cations and to follow the peculiarities of their formation and reactivity.…”

“…Aliphatic diketones (readily available and widely used in different areas of chemistry) may provide a suitable class of models for the studies of correlation between molecular structure of bridged bifunctional compounds and the properties of ionized species. The radical cations of simple aliphatic ketones are characterized by n σ -type SOMO localized at the carbonyl oxygen atom. , We are unaware of any experimental or theoretical works on diketone radical cations. In addition to general modeling, an interesting aspect is concerned with the well-known effect of keto-enolic tautomerism, which makes it possible to characterize both ketonic and enolic forms of radical cations and to follow the peculiarities of their formation and reactivity.…”