Electrochemical Studies on Some Sulphonamoylazonitropyrazoles

School of Studies in Chemistry, Jiwaji University, Gwalior-474 011

Manuscript received 30 July 1997, revised 18 February 1998, accepted 27 February 1998

The electrochemical reduction of 1-nitrophenyl-3-aminophenyl-5-methyl-4-(4'-sulphonamoyl)azopyrazoles has been studied over a wide pH range at dropping mercury and glassy carbon electrodes. The compounds give one four-electron wave corresponding to the reduction of nitro group, and one two-electron wave corresponding to the reduction of N=N group. On the basis of polarography, cyclic voltammetry, coulometry and controlled potential electrolysis, a reaction mechanism, has been suggested to account for the reduction mechanism.