Perfluorinated Polycyclic Aromatic Hydrocarbons: Anthracene, Phenanthrene, Pyrene, Tetracene, Chrysene, and Triphenylene

Xuejun Feng, Qianshu Li, Jiande Gu, F. Albert Cotton, Yaoming Xie and Henry F. Schaefer III

The properties of perfluoroanthracene (1-C14F10), perfluorophenanthrene (2-C14F10), perfluoropyrene (C16F10),
perfluorotetracene (1-C18F12), perfluorochrysene (2-C18F12), and perfluorotriphenylene (3-C18F12) and their radical
anions have been studied using density functional theory (DFT). Three measures of neutral-anion energy
separations reported in this work are the adiabatic electron affinity (EAad), the vertical electron affinity (EAvert),
and the vertical detachment energy (VDE). The vibrational frequencies of these perfluoro PAHs and their
radical anions are also examined. The predicted adiabatic electron affinities (DZP++ B3LYP) are: 1.84 eV,
1-C14F10; 1.41 eV, 2-C14F10; 1.72 eV, C16F10; 2.39 eV, 1-C18F12; 1.83 eV (Ci symmetry) and 1.88 eV (C2
symmetry), 2-C18F12; and 1.69 eV, 3-C18F12. The perfluorotetracene is clearly the most effective electron
captor. Perfluorophenanthrene, perfluoropyrene, perfluorochrysene, and perfluorotriphenylene, as well as their
radical anions deviate from planarity. For example, the nonplanar perfluorochrysene structures are predicted
to lie 7-13 kcal/mol below the pertinent C2h stationary points.