Folded or nonfolded fluorophores incorporating naphthalene: Their fluorescent quenching driven by charge transfer or co-aggregation in the aqueous–organic binary solvent

Folded or nonfolded fluorophores incorporating naphthalene were synthesized and characterized by steady state fluorescence technique. Paraquat as an excellent quenching reagent quenched the fluorescence of Ne16 or nDs (n = 1–4) driven by charge transfer. Under aggregation of nDs, α-CD did not quench the fluorescence of 1D. At lower concentration, the quenching tendency of α-CD against nDs is 2D > 3D > 4D, while at higher concentration, the tendency is 2D < 3D < 4D. α-CD showed the selective recognition on its fluorescent quenching against 1D, 2D, 3D and 4D.