Electrochemical characterization of isatin-thiosemicarbazone derivatives

Herein, we have notably described the electrochemical behavior of four isatin-thiosemicarbazone derivatives. In this regard, cyclic voltammograms of isatin-3-thiosemicarbazone ( ITSC ), isatin-3-(N 4 -benzylthiosemicarbazone) ( ITSC-Ph ), 1-(5-nitro-2-oxoindolin-3-ylidene)thiosemicarbazide ( NO 2 -ITSC ) and 1-(5-nitro-2-oxoindolin-3-ylidene)-4-phenylthiosemicarbazide ( NO 2 -ITSC-Ph ) have demonstrated an irreversible oxidation process. More specifically, the generation of isatin and thiourea moieties as the final oxidation products was proposed. The cyclic voltammograms also demonstrate irreversible reduction processes of ITSC and ITSC-Ph in three steps. The proposed final products are 3-aminoindolin-2-one and thiourea moieties. In the cyclic voltammograms of NO 2 -ITSC and NO 2 -ITSC-Ph , five reduction processes were observed: three of them due to reduction of the nitro group. It was proposed that the formation of 5-hydroxyamino-3-iminoindolin-2-one and the thiourea moieties would be the final products. Graphic abstract Electrochemical characterization of four isatin thiosemicarbazone derivatives is described. The compounds are irreversibly oxidized and reduced. Isatin moieties and thiourea are proposed to be the products generated after oxidation. Considering the reduction processes, the nitro group present at the isatin moiety is also reduced and influences the reduction products generated.