Square-wave voltammetry of 4,4′-diisopropyl-2,2′-bithiazoline and its complex with copper(II)

(4S)‐4′‐diisopropyl‐2,2′‐bithiazoline (DPT) is an electroactive organic chiral compound giving two reduction responses in square‐wave voltammograms at potentials about −0.2 and −0.4 V by forming a complex with mercury which deposits at the electrode surface. By the addition of copper(II) ion to the solution of DPT a third peak appears between them at about −0.3 V, which corresponds to the reduction of adsorbed Cu‐DPT complex. Optimal pH for the investigation of those redox processes was found to be 2.8. By square‐wave voltammetric measurements it was interpreted that these redox reactions were quasireversible with immobilized reactants. By plotting ip/f vs. frequency a quasireversible maximum was obtained, and the apparent standard reaction rate constants were calculated: log (ks)DPT=(0.91 ± 0.9) and 1 < ks < 65S−1, log (ks)CuDPT= (0.35 ± 0.9) and 0.3 < ks < 18 S−1 in 0.55 M NaCl.