Self‐Organization of Hyperbranched Polyesters Functionalized with Pyrrolo[2,1‐a]isoquinoline End Groups and Their Fluorescent Recognition of Anthracene and Pyrene

The structurally controllable hyperbranched aromatic–aliphatic copolyesters HBPE‐MPICB 4 and HBPE‐MPICB 2 are synthesized by incorporating the periphery of a second‐generation hyperbranched polyester (HBPE) with methylpyrrolo[2,1‐a]isoquinoline‐1‐carbonitrile(E)‐4‐oxo‐[2‐(oxo‐λ 3 ‐methyl)hydrazinyl]but‐2‐enoate (MPICB) groups via one‐pot synthesis. Organized supramolecular structures are self‐assembled in different organic media. Lamellar structure with a length of around 10 µm can be obtained in ethyl acetate. However, the identical HBPE‐MPICB 4 and HBPE‐MPICB 2 building blocks can self‐organize into flower‐like and vesicular structure in ethanol, with particle sizes around 12 and 5 µm, respectively. The noncovalent interactions of HBPE‐MPICB 4 and HBPE‐MPICB 2 , that is, hydrogen bonding and π–π stacking, are critical for the construction of organized structures. Furthermore, host–guest recognitions by HBPE‐MPICB 4 and HBPE‐MPICB 2 are investigated by fluorescence studies. The results indicate that HBPE‐MPICB 4 microflowers respond selectively to anthracene and pyrene through π–π stacking interactions.