The absorption and fluorescence spectra of DSMI with CB[n]s
were measured in water. The fluorescence titration experiments
were performed as follows: 25 ml of 1.0 103 mol/l stock solution
of DSMI and various amount of 2.0 105 mol/L of CB[6] aqueous
solution were transferred into a 5 ml volumetric flask, then the
volumetric flask was filled to the final volume with distilled water.
Fluorescence and absorption spectra were measured after 3 min of
ultrasonic agitation. The NMR spectra were obtained in D2O with
DSS (3-(trimethyl-silyl)-1-propanesulfonic acid sodium salt) as
internal standard; the protonation form of DSMI was determined
by the color of the solution changing from yellow to colorless, and
then the pH of the solution was checked by pH test paper.