The structure and dynamics of 1,3,5-cycloheptatriene and 1,3-cycloheptadiene radical cations in low-temperature matrices. An ESR investigation

ESR spectra of the radical species derived from ⁶⁰Co γ-ray irradiation of 1,3,5-cycloheptatriene (1,3,5-CYT) and 1,3-cycloheptadiene (1,3-CYD) in halocarbon matrices have been studied in the temperature range 70-103 K. Ring inversion across the molecular plane occurs in the radical cation 1,3,5-CYT^{+{radical dot}} in CCl₃CF₃, the activation energy being 1.7 kcal/mol. Above 90 K, 1,3,5-CYT^{+{radical dot}} is deprotonated thermally in CCl₂FCClF₂. No dynamical effect has been observed for 1,3-CYD^{+{radical dot}}.