Photoinduced energy transfer in bichromophoric co-assemblies based on amphiphilic poly(amidoamine) dendrons

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 Dn  Py, where n=1n=1, 2, 3 denotes the generation of dendrons) in water at a concentration of 3.0×10−6 M3.0×10−6 M, lower than the individual critical aggregation concentrations (CAC) of either DnCz I or Dn  Py. 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 π–ππ–π stacking and the dendritic branches served as connectors due to the hydrogen-bonding interaction.

Graphical abstractSpherical co-assemblies were generated from the mixture of poly(amidoamine) dendrons modified with carbazole and/or pyrene chromophores. Energy transfer from carbazole to pyrene units occurred efficiently within these co-assemblies.Figure optionsDownload full-size imageDownload as PowerPoint slide