SPECTROPHOTOMETRIC AND POLAROGRAPHIC STUDIES OF DI-2-PYRIDYL KETONE 2-THIENOYLHYDRAZONE

The spectral and differential pulse polarographic (DPP) behaviour of d i-2-pyridyl ketone 2-thienoylhydrazone (DPKTH) has been investigated i n 30% (v/v) ethanol-buffer mixtures over a wide range of pH (2.0-12.0) . The spectral bands located at 325, 276. 230 and 208 nm of the DPKTH in ethanol are assigned to the possible electronic transitions of the molecule. The spectral data at various pH values indicates that the mo lecule characterized by the keto = enol tautomerization and the pK(a) value for the enolic form of the compound is determined in aqueous eth anol and was found to be 10.6. The effect of various operational param eters on the reduction current and the mechanism of the electrode reac tion of DPKTH at the DME are discussed. The main reduction peaks are a ttributed to the reduction of C=N centre of both the keto and enol for ms. This behaviour is compared with the DPP behaviour of the other rel ated acid hydrazone compounds. The applicability of DPP technique for the trace determination of DPKTH was tested under the optimum experime ntal conditions and the detection limit is found to be 0.09 mu m.