Electrochemiluminescence of 9,10-Dichloroanthracene at Low Temperatures

Abstract
The electrochemiluminescence (ECL) of 9,10-dichloroanthracene in methylene chloride was investigated at temperatures as low as −60°C. The cation was quite stable and the anion was unstable at room temperature. The anion, however, increased its stability as the temperature decreased and below ca. −40°C it was essentially stable. Temperature was also found to have great influence on the relative intensity of the two spectral components of the ECL of 9,10-dichloroanthracene. By lowering the temperature the components at the longer wavelength increased strongly compared with the other component. When the ECL was observed by applying a rectangular potential, the intensities of the two components decayed exponentially with the same decay constant. Therefore, it was concluded that the emission at the longer wavelength originated not from the products of electrolysis but from the excimer and that the primary process to produce these two emissions was the same.