Differential pulse voltammogram (DPV) of 1.0 104 M RD (host) in the
absence and presence (3.0 equivalent each) of the various metal ions in CH3CN;
electrolyte, 0.01 M TBPA; pulse amplitude, 50 mV within the potential range of
0.2–1.2 V vs. Ag/Agþ. (For interpretation of the references to color in this figure
legend, the reader is referred to the web version of this article.)