Host–Guest Recognition and Fluorescence of a Tetraphenylethene‐Based Octacationic Cage

Abstract

AbstractWe report the synthesis and characterization of a three‐dimensional tetraphenylethene‐based octacationic cage that shows host–guest recognition of polycyclic aromatic hydrocarbons (e.g. coronene) in organic media and water‐soluble dyes (e.g. sulforhodamine 101) in aqueous media through CH⋅⋅⋅π, π–π, and/or electrostatic interactions. The cage⊃coronene exhibits a cuboid internal cavity with a size of approximately 17.2×11.0×6.96 Å3 and a “hamburger”‐type host–guest complex, which is hierarchically stacked into 1D nanotubes and a 3D supramolecular framework. The free cage possesses a similar cavity in the crystalline state. Furthermore, a host–guest complex formed between the octacationic cage and sulforhodamine 101 had a higher absolute quantum yield (ΦF=28.5 %), larger excitation–emission gap (Δλex‐em=211 nm), and longer emission lifetime (τ=7.0 ns) as compared to the guest (ΦF=10.5 %; Δλex‐em=11 nm; τ=4.9 ns), and purer emission (ΔλFWHM=38 nm) as compared to the host (ΔλFWHM=111 nm).