Spectral features of electrochemiluminescence accompanying reduction of aryldiazonium salts on a copper cathode

Spectra of electrochemiluminescence (ecl) accompanying reduction of selected aryldiazonium cations (ADAC), originating from tetrafluoroborate salts, on a copper electrode were measured and compared with known fluorescence spectra of some expected products. In addition, changes of integral ecl intensity in time and its dependence on cathodic current density were investigated to shed more light on the nature of this phenomenon. With the aid of PM3 CI method it was possible to interpret ecl spectra and state that ecl occurs as a result of the recombination of two primarily formed azophenyl radicals or azophenyl and phenyl radicals ¯ created upon N2 elimination from the former entities.