Electrogenerated chemiluminescence .60. Spectroscopic properties and electrogenerated chemiluminescence of decaphenylanthracene and octaphenylnaphthalene

The spectroscopic properties and electrogenerated chemiluminescence (ECL) of octaphenylnaphthalene (OPN) and decaphenylanthracene (DecPA) have been investigated. OPN displays a featureless fluorescence band at 424 nm and a fluorescence quantum yield of 0.06, while DecPA exhibits a structured fluorescence emission at 486 nm and a quantum yield of 0.10. Cyclic voltammetric measurements reveal the formation of radical cations and radical anions for both compounds, all of which appear relatively stable, although OPN.+ decomposes at scan rates below 200 mV s(-1). The ECL spectrum of OPN, generated by sequential production of the radical cation and radical anion of the compound at an electrode surface, is broad and red-shifted by about 100 nm from the compound's fluorescence maximum. This indicates that the emission is not that of OPN, but of a decomposition product, presumably derived from the unstable radical cation. DecPA, however, displays very stable green ECL similar in energy to its fluorescence spectrum.