Abstract
The polarographic behavior of 5-phenylazo-2-thiobarbituric acid and 5 of its substituted derivatives was investigated in a buffer solution of pH (2-12). A mechanism for the reduction pathway is suggested. Based on the results of the nitro derivative, the coupling product of 2-thiobarbituric acid with diazonium salt is most probably in the azo and not the hydrazone form. The most reliable E1/2 values at different pH's were correlated to Hammett's σ constant which reflected a fair correlation.
