Photoinduced energy transfer in bichromophoric co-assemblies based on amphiphilic poly(amidoamine) dendrons
Bing-Bing Wang1, Min Gao, Xin-Ru Jia
1Beijing National Laboratory for Molecular Sciences, Key Laboratory of the Polymer, Chemistry and Physics of the Ministry Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Abstract:
Spherical co-assemblies were generated from an equivalent-molar-ratio mixture of amphiphilic poly(amidoamine) dendrons that were modified with focal carbazole and/or pyrene chromophores from the first to the third generation (DnCz I and DnPy, where n=1, 2, 3 denotes the generation of dendrons) in water at a concentration of 3.0 x 10(-6) M, lower than the individual critical aggregation concentrations (CAC) of either DnCz I or DnPy. UV-vis absorption and fluorescence emission spectra indicated that fluorescence resonance energy transfer (FRET) from carbazole to pyrene units occurred efficiently within the co-assemblies. Further study implied that part of the carbazole and/or pyrene units stacked homogeneously in the co-assemblies via pi-pi stacking and the dendritic branches served as connectors due to the hydrogen-bonding interaction.
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