Fig. 4: Exploration of potassium ion transport mechanism.
a K+ transport activities of 3 under alternative UV and Vis light irradiations, supporting the notion that reversible photoisomerization is independent of H. b Ion transport selectivity of t-3 and c-3 determined by varying the extravesicular MCl salts; here, RM+ = (IM+ – I0)/(ITriton – I0) whereas IM+ and I0 are the ratiometric values of I460/I403 at t = 300 s before addition of triton, and ITriton is the ratiometric value of I460/I403 at t = 300 s right after addition of triton. c The chloride-sensitive SPQ assay, employing SQP dye whose fluorescence is quenched by Cl- anions and demonstrating 3 does not transport Cl−. d The HPTS assay in the presence of proton carrier FCCP, confirming 3-mediated K+ transport rate to be faster than H+. SPQ 6-Methoxy-N-(3-sulfopropyl)quinolinium, FCCP carbonyl cyanide-p-trifluoromethoxyphenylhydrazone.
