Umbrella-Shaped Amphiphiles: Internal Alkylation of an Aromatic Micelle and Its Impact on Cavity Features.

To develop new hybrid micelles with alkyl/polyaromatic core-shell structures, we synthesized umbrella-shaped amphiphiles bearing a bent anthracene dimer with a linear alkyl chain (i.e., octyl and hexadecyl groups). The amphiphiles quantitatively assemble into spherical micelles (~2-3 nm in core diameter), possessing an alkylated cavity surrounded by a polyaromatic framework, in water. The alkylation significantly enhances the stability of the micellar structures against dilution (up to 9 μM) and heat (up to >120 ºC). The highly condensed hexadecyl core of the hybrid micelle, as indicated by solvatochromic guest probes, displays increased uptake ability toward large alkylated metallodyes. Interestingly, efficient uptake of aromatic macrocycles (i.e., [n]cycloparaphenylenes) by the present micelle provides pseudorotaxane-shaped host-guest composites with high emissivity (ФF = up to 35%). Internal multi-alkylation of an aromatic micelle can thus successfully enhance its assembly stability/guest uptake functions.