CYCLIC VOLTAMMETRY AND SPECTRAL STUDY OF SOME PHENYL AMINO 3,6-DINITROCOUMARIN DERIVATIVES

Four derivatives of phenylamino-3,6-dinitrocoumarin were investigated in the present workusing coupled electrochemical and “in-situ” absorption and EPR spectral techniques. The cyclicvoltammograms recorded in dimethyl sulphoxide (DMSO) – 0.1 M tetra buthylammoniumperchlorate (TBAP), with both stationary and rotating (RDE) platinum electrodes, evidence anECE sequence for the reduction mechanism. EPR spectra attest the presence of twoparamagnetic species, assigned respectively to the anion- and dianion-radicals. UV-VIS spectrarecorded during the electrolysis at the potential corresponding to the second electron transfersustain this assignment. The experimental data are well accounted for by semiempiricalcalculations (AM1 Hamiltonian, MOPAC-program package) of the redox properties.