Characteristic Fluorescence Behavior of Dialkynylpyrene Derivatives in Hydrophobic Cavity of Protein

Water-soluble fluorescent molecules consisting of dialkynylpyrene skeleton with an oxyethylene unit were designed and synthesized for interacting with hydrophobic cavities of proteins. In the presence of serum albumin, the fluorescent spectra of dialkynylpyrene derivatives were remarkably changed. These behavior can be explained by monomer–excimer emission switching and twisted intramolecular charge-transfer mechanism.