LAUSR

Abstract Understanding relationships between molecular structures and fluorescent properties is critical to enable rational deployment of fluorophores. 1-Acetylpyrene is an important pyrene-derivative, used extensively as an environment-sensitive probe. In the past, the fluorescence of 1-acetylpyrene was considered to be polarity-sensitive with a large positive solvatochromism, and its monomer emissions were believed in the range of 410-470 nm. In this paper, our experimental and theoretical studies showed that the monomer fluorescence of 1-acetylpyrene is centered at ∼390 nm, which is similar to that of pyrene dyes and not polarity-sensitive. Previously observed “monomer emission” has been re-assigned to that of dimers, which represent the dominant existence form of 1-acetylpyrene in the solution phase, as a result of strong intermolecular π-π stacking interactions.