(a) UV–vis
spectra of (Ra)-2 in dichloroethane (10–5m) initially
(purple), after irradiation at 365 nm for 12 min
at 10 °C (orange), and after keeping in the dark for 50 min at
10 °C (green); (b) UV–vis spectra of (Sa)-2 in dichloroethane (10–5m) initially (purple), after irradiation
at 365 nm for 2 min at 10 °C (orange), and after keeping in the
dark for 25 min at 20 °C (green); and (c) CD spectra of the first
eluted fraction (F1) of (Sa)-2S and the second eluted fraction (F2) of
(Sa)-2S in dichloroethane at room temperature, after
irradiation at 365 nm, and after THI after keeping in the dark at
room temperature.