The 13C Hyperfine Splittings in ESR Spectra of Prop-2-ynyl and 1-(Trimethylsiloxy)prop-2-ynyl Radicals

Article abstract of DOI:10.1016/0022-2364(83)90191-9

The 13C satellite lines were observed in the 9.4 GHz ESR spectra of prop-2-ynyl and 1-trimethylsiloxyprop-2-ynyl radicals generated from precursors containing 13C in natural abundance.The 13C hfs indicate that prop-2-ynyl radicals adopt the ?-delocalized structure, not the ?-allenyl form.The hfs of 1-trimethylsiloxyprop-2-ynyl radicals indicate that there is appreciable delocalization of spin onto the trimethylsiloxy group and that the radical is essentially planar at C(1).A linear correlation of a(C) with a(H) is shown to hold for a number of neutral hydocarbon ?-delocalized radicals.The experimental hfs are compared with spin densities calculated by a variety of semiempirical and ab initio SCF MO methods.