Fig. 4: The mechanism of photochemical transformation from 3Abf-Ofn to Bfa.

a C-H···π interactions and dihedral angle of photoproduct Bfa. b Calculated energy and molecular orbital diagrams of HOMOs and LUMOs for photoreaction compound Bfa and 3Abf-Ofn, respectively. c FT-IR patterns of 3Abf-Ofn sample before and after UV irradiation. d High-resolution F 1 s XPS spectra of 3Abf-Ofn before UV irradiation. e High-resolution F 1 s XPS spectra of 3Abf-Ofn after UV irradiation for 10 min. f Energy profile of the reaction by DFT calculations.