Electrochemil uminescence of pyrene in acetonitrile

Abstract

The e.c.l. of pyrene in acetonitrile has been studied using a controlledpotential double-step method, and the following results were obtained: (1) the electrode potential regions where the emission was observed were in agreement with those of cation and anion formation; (2) the e.c.l. spectrum had two main bands at 400 nm and 470 nm and a subsidiary band at the longer wavelength; (3) the peak wavelengths of the two main bands concided with those of the monomer and excimer fluorescences of pyrene; (4) the intensity ratio of the two main bands is linearly dependent on the concentration of pyrene. From these results, we conclude that the e.c.l. of pyrene is most probably composed of the emission bands of monomer and excimer fluorescences of pyrene including some impurity emission at longer wavelengths, and that a considerable amount of the excimer is produced directly by the electron transfer reaction between cation and anion radicals of pyrene.