Fig. 4. Wavelength-switching experiment for the visible light-mediated ATRA reaction of C₈F₁₇I with 5-hexen-1-ol to form 3b using 1 as PC and TEA as sacrificial reductant (see ESI† for details regarding the set-up) as support for the involvement of conPET; absorption spectra normalised to 1. (A) A solution of 1 (0.357 mM), 5-hexen-1-ol (71.4 mM), TEA (23.6 mM) & mesitylene (15 μL, internal standard) in acetonitrile : methanol (4 : 3) was irradiated at 525 nm for 25 min; absorption spectrum of the reaction solution containing 1 (red line). (B) Absorption spectrum of the reaction solution containing in situ generated 2 (brown line); addition of C₈F₁₇I (95 mM). (C) Reaction solution after addition of the perfluoroalkyl halide and irradiation at 700 nm for 60 min; 5% NMR yield of product 3b. (D) Reaction solution after addition of perfluoroalkyl halide and storing in the dark for 1 h; no formation of 3b.