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  cm 2 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  cm 2 s −1 which is close to that measured at pH 3.9.