Self‐Assembly of Metallo‐Supramolecular Amphiphiles based on Azadipyrromethenes: Consecutive Pathways to Nanodiscs and Nanosheets

Abstract A new class of metallo‐supramolecular amphiphilic dyes 1 a , b was constructed by using two azadipyrromethene units which were respectively modified with two hydrophobic alkyl and two hydrophilic oligo(ethylene glycol) chains. The spectroscopic and morphological studies revealed the consecutive self‐assembly pathways of 1 a in EtOH/H 2 O mixed solvent. The monomers of 1 a firstly aggregated into the kinetic‐controlled, nanodisc‐shaped Agg. I upon cooling and the latter spontaneously transformed into the thermodynamically more stable Agg. II with a nanosheet morphology. While the non‐fluorescent Agg. I displayed a broad absorption band ( λ max =615 nm), the Agg. II displayed a more intensive and narrowed J‐band ( λ max =693 nm) and a fluorescence band with a maximum at 760 nm ( Φ fl =0.1), which could be ascribed to the J‐aggregation induced emission enhancement. The kinetics of Agg. I to Agg. II transformation was further modulated by seed‐initiated supramolecular polymerization with various ratios of Seed agg.II , in which the transformation rate was significantly increased by ca. 2 orders of magnitude compared to the spontaneous process. The supramolecular amphiphile 1 b bearing longer hydrophilic chains formed only one type aggregate, which exhibited spectroscopic and morphological properties that were highly comparable with that of Agg. I .