Fig. 2. Solid-state NMR experiments used to determine intermolecular ¹³C-¹⁹F distances.

(A) ¹³C{¹⁹F}REDOR spectra (100 MHz) of 14-F-AmB/skipped-¹³C-AmB/Erg/POPC = 0.5:0.5:3:7 hydrated with 10 mM Hepes containing D₂O at 25°C. The sample spinning speed was 7 kHz, and the dephasing time was 16 ms. The full echo (S₀, bottom, black), REDOR-dephased (S, bottom, red), and difference (ΔS, top) spectra clearly showed a reduction in the peak intensity of the C41, heptaene, and C1′ signals; * and ^# indicate the signals attributed to POPC and Erg, respectively. (B) REDOR dephasing observed for C1′ (filled black), C41 (filled red), and heptaene (filled blue) upon irradiation at 14-F and for C26 (open black) and C40 (open red) upon irradiation at 32-F. The error bars denote the signal-to-noise ratios of ΔS signals. (C) ¹³C-labeled positions of the skipped labeled (22) and synthetic AmBs shown with orange circles. Arrows denote the interatomic distances determined by REDOR and are colored in the same manner as the dots in (B).