Electrogenerated Chemiluminescence of 9,10-Diphenylanthracene, Rubrene, and Anthracene in Fluorinated Aromatic Solvents

Abstract

The electrogenerated chemiluminescence (ECL) of 9,10-diphenylanthracene (DPA), rubrene, and anthracene has been studied in fluorinated aromatic solvents. Mixed annihilation ECL between aromatic luminophores and quinones was observed in solvent systems containing acetonitrile and either benzene, benzotrifluoride, 3-fluorobenzotrifluoride, or 1,3-bis(trifluoromethyl)benzene. Increases in ECL efficiency (φecl, photons generated per redox event) correlated with decreasing solvent polarity when 1,4-benzoquinone was used as a nonemitting ECL partner. However, opposite results were observed using 1,4-naphthaoquinone (NQ) as a nonemitting partner. φecl also correlated with radical anion stability of NQ in these solvent systems, as indicated by reverse/forward current ratios (Ir/If), suggesting noncovalent interactions between the solvent and the nonemitting ECL partner. Specifically, the reaction of an aromatic luminophore with 1,4-naphthoquinone in acetonitrile/benzotrifluoride showed a 1.03-1.63-fold increases in ECL efficiency over that of acetonitrile/benzene. Slight blue shifts (∼3 nm) in photoluminescence and ECL emissions were seen as solvent polarity increased. Reaction enthalpies of each system were estimated using half-wave potentials of oxidation and reduction and were found to correlate well with emission energy.

Department(s)

Chemistry and Biochemistry

Document Type

Article

DOI

https://doi.org/10.1021/jp804418f

Keywords

yydrocarbons, aromatic compounds, solvents, polarity, Quantum mechanics

Publication Date

2008

Journal Title

The Journal of Physical Chemistry A

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