Host‐Guest Complexes of Pillar[5]arene as Components for Supramolecular Light‐Harvesting Systems with Tunable Fluorescence

A guest molecule containing a short alkyl spacer between the tetraphenylethylene group and the methylpyridinium group was designed and synthesized. After complexation with a water‐soluble pillar[5]arene, the resulting host‐guest complex can further self‐assemble into fluorescence‐emitting nanoparticles in water. By loading a commercially available dye Rhodamine 6G into the nanoparticles, an efficient artificial light‐harvesting system with high donor/acceptor ratios (>400/1) was successfully constructed. The obtained systems show considerable antenna effects with values of more than 10 times. The system also exhibits tunable fluorescence emission behavior and can be used as a fluorescent ink for information encryption.