C^{+{radical dot}}₁₀ and C^{+{radical dot}}₇ carbon cluster ions from overcrowded octachloropentafulvalene and octachloronaphthalene

Ions C^{+{radical dot}}₁₀ and C^{+{radical dot}}₇ were produced by dissociative electron impact ionization from octachloropentafulvalene and octachloronaphthalene and studied by MS/MS techniques: unimolecular MIKES, CAD, and charge stripping. Elimination of C₃ is the major fragmentation reaction of both ions in the metastable time frame. Kinetic energy releases indicate negligible activation barriers along the reaction coordinate for dissociation. The present findings are discussed in the light of recent experimental studies of carbon cluster ions by laser vaporization techniques and calculations concerning structures of carbon ion clusters. The possibilities of monocyclic C^{+{radical dot}}₁₀ and/or fused bicyclic octadehydronaphthalene C^{+{radical dot}}₁₀ are raised. The results illustrate a general method for studying C^{+{radical dot}}_n species generated by exhaustive halogen elimination from perhalo conjugated hydrocarbons.