Dual Stimuli-Responsive Cross-Linked AIE Supramolecular Polymer Constructed through Hierarchical Self-Assembly

Herein, we report the successful construction of a new family of dual stimuli-responsive AIE cross-linked supramolecular polymer through the strategy of hierarchical self-assembly. A novel dipyridyl donor building block G1 containing tetraphenylethylene (TPE) moiety was designed and synthesized. Notably, two nitrile units were attached onto G1, which were employed as the guest for the further host-guest interaction with pillar[n]arene derivatives. The rhomboidal metallacycle G2 with four nitrile units was firstly constructed through coordination-driven self-assembly. Subsequently, the cross-linked supramolecular polymers H₂⊃G2 were then generated through host-guest interactions. It should be noted that the obtained supramolecular polymer displayed interesting AIE properties due to the restriction of TPE intramolecular motions within the polymeric network. More importantly, by taking advantages of dynamic nature of both coordination bonds and host-guest interactions, the resultant supramolecular polymer displayed dual stimuli-responsive fluorescent transitions under different stimuli such as the competitive guest and halide anion.