title: The formation of RCCCO and CCC(O)R (R = Me, Ph) neutral radicals from ionic precursors in the gas phase: the rearrangement of CCC(O)Ph.
abstract: Neutrals MeCCCO, CCC(O)Me, PhCCCO and CCC(O)Ph have been made by neutralisation of [MeCCCO](+), [CCC(O)Me](-), [PhCCCO](+) and [CC(CO)Ph](-). Neutrals MeCCCO, CCC(O)Me and PhCCCO are stable for the microsecond duration of the neutralisation experiment. A joint experimental and theoretical study (energies calculated at the B3LYP/aug-cc-pVDZ//B3LYP/6-31G(d) level of theory) suggests that the neutral radical CCC(O)Ph rearranges via a four-centred ipso radical cyclisation/ring opening to form the isomer PhCCCO in an exothermic reaction. (13)C labelling confirms that the rearrangement does not involve O migration. Some of the PhCCCO radicals formed in this reaction are sufficiently energised to effect decomposition to give PhCC and CO.
authors.affiliation: Department of Chemistry, The University of Adelaide, South Australia, 5005.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Peppe
authors.forename: Andrew M
authors.initials: AM
authors.lastname: McAnoy
authors.forename: Suresh
authors.initials: S
authors.lastname: Dua
authors.forename: John H
authors.initials: JH
authors.lastname: Bowie