The Electrochemical Behavior of p‐Sulfonated Sodium Salt of Calix[6]arene

The water-soluble p-sulfonated sodium salt of calix[6]arene (p-SC6) is synthesized and characterized by FT-IR and UV-vis spectra. The purity of the product is checked as 97.6% by HPLC. The electrochemical behavior of p-SC6 in NaAc+HAc (pH 3.9) buffer solution is studied. The results showed that p-SC6 can be oxidized irreversibly when the potential scanned from 0 to 1.0 V (vs. SCE). The peak potential locates at about 0.83 V (vs. SCE) which depends on the scan rate and acidity. The number of electrons, n, transferred in the electrochemical reaction is 1. The diffusion coefficient of p-SC6 is 1.4×10−6 cm2 s−1 at 25 °C. The electrochemical oxidation of p-SC6 is strongly affected by acidity. For example, when pH is 10.6, n becomes 3. But the diffusion coefficient of p-SC6 is 1.1×10−6 cm2 s−1 which is close to that measured at pH 3.9.