A Photolockable Polyaromatic Capsule Designed via Regiochemical Substitution.

Abstract

Photocontrol over host frameworks is an elegant way to manipulate host-guest composites, yet the majority of previous systems suffer from long irradiation time and narrow guest scope, and are restricted to intramolecular photoreactions in organic solvents. Herein we present a photolockable polyaromatic capsule with improved guest binding abilities in water. The capsule assembles from bent amphiphiles featuring two 2-subsutituted anthracene panels, which shows high stability against dilution and undergoes intermolecular [4+4] photo-oligomerization upon short light irradiation (<10 min). The photolocked capsule provides a roughly spherical framework, with an average, core diameter of ~3 nm, composed of amphiphilic oligomers (e.g., trimer). The new capsule shows improved host ability (up to 10-fold) in water toward various hydrophobic compounds (e.g., organic and metal-complex dyes), as compared with an analogous, non-photolockable capsule with 9-subsutituted anthracene panels. In addition, the resultant dye-loaded capsules are also successfully photolocked via short irradiation with high retention of the bound dyes.