Photochemical Reversibility of Ring-Closing and Ring-Opening Reactions in Diarylperfluorocyclopentenes

Abstract

Time dependent density functional theory (TDDFT) is used to study the important factors that control the photoisomerization of diarylperfluorocyclopentenes. The calculations are carried out for free molecules and for diarylperfluorocyclopentenes perturbed by gold atoms. Potential energy surfaces for the cyclization reaction are obtained for the ground state and for the excited states involved in the photoswitching. Analysis of the computed UV/vis spectra, the excitation energies, and the spatial distribution of the frontier orbitals of both unperturbed and perturbed molecules give an inside view of the ring opening and the ring closing. The bonding interaction in the unoccupied orbials is considered to be the driving force for the photochemical cyclization while the antibonding interaction significantly hinders the reaction. The obtained theoretical results are in good agreement with the experimental data and provide an explanation of the one-directional and bidirectional photoswitching of diarylperfluoro...