Long-range proton hyperfine couplings in radical cations of carbonyl compounds

Abstract

Large non-aldehydic ¹H hyperfine couplings in the radical cations of four carbonyl compounds are assigned to long-range hyperfine interactions relayed through a trans(W-plan) arrangement of C–C and C–H σ bonds; for example, the two strongly coupled hydrogens in the cyclohexanone radical cation are identified by deuterium substitution as the ‘δ’ equatorial pair at C-3 and C-5 rather than the ‘γ’ equatorial pair at C-2 and C-6 assigned previously.