Synthesis, spectroscopic and voltammetric studies of a novel Schiff-base of cysteine and saccharin

In this study, a novel Schiff-base of cysteine and saccharin [(2R)-2-(1, 1-dioxo-1, 2-dihydro-1λ6-benzo[d]isothiazol-3-ylideneamino)-3-mercapto-propionic acid] was synthesized and characterized by UV–Vis, FT-IR, 1H NMR and elemental analysis. The voltammetric behaviour of Schiff-base was investigated on the static mercury drop electrode (SMDE) by using Square-Wave voltammetry (SWV) and Cyclic voltammetry (CV). The voltammograms of the Schiff-base gave three reduction waves in Britton–Robinson buffer (pH 5.0–9.0) for the potential range from 0.0 to −1.4 V. The first reversible cathodic peak is due to reduction of the mercury thiolate, produced by the thiol group of Schiff-base which adsorbs at Hg electrode surface, to metallic mercury and free thiol. The second reduction peak may be assigned to the reduction of azomethine center (>CN) in the Schiff-base and the last peak may be related to the catalytic hydrogen reduction.