The authors synthesized the electron-rich 1,5-dioxonaphthyl group incorporated foldamers,and linear donors and electron-deficient pyromellitic diimide incorporated foldamers,which were investigated in organic solvents. There is an evident charge transfer process from the donors to the electron-deficient foldamers,due to the donor-acceptor interaction of the heteroduplexes formed from the donors and the electron-deficient foldamers in chloroform,observed by using the ultraviolet(UV) visible method. The charge transfer process of the heteroduplexes depends on the molecular structure(not only the number of 1,5-dioxonaphthyl groups and pyromellitic diimide groups in the heteroduplex,but also the intermolecular double hydrogen bond in the heteroduplex),the intercalative π-π stacking motif,the initial concentration of heteroduplexes,and the polarity of the solvent. Fortunately,the authors found a critical bumping concentration(CBC) of the donors in acetonitrile or chloroform,which is useful in quantitative research,by using the fluorescence method. The value of CBC depends not only on intramolecular folding and the intramolecular hydrogen bond,but also on intramolecular π-π stacking and the solvent. The electron-deficient foldamers quenched the fluorescence of the donors. Fluorescence quenching depends not only on the number of pyromel-litic diimide groups and 1,5-dioxonaphthyl groups in the heteroduplex,but also on the intercalative π-π stacking motif between the donor and the acceptor.
