Figure 6.

¹H NMR spectra of 2-S (bottom) and 2-SO₂ obtained by modification with DMDO for 0 min and 5 min before work-up (above). Arrows show indicative shifts upon modification. The selectivity of the modification was evaluated by treating the starting polymer with a large excess of DMDO for prolonged time (24 h, 3.0 equiv). Further control experiments were carried out by treating 2-F with DMDO for 5 min, resulting in no change of the ¹H NMR spectrum (top). Arrows show indicative shifts upon modification: (a) downfield shift of the peak of the benzothiadiazole proton by oxidation to the sulfone and (b) upfield shift of the aliphatic protons next to the thioalkyl sulfur upon oxidation to the sulfone. See Supplementary Material for full spectra.