Pillar[5]arene-based supramolecular AIE hydrogel with white light emission for ultrasensitive detection and effective separation of multianalytes

Abstract

Light-emitting materials are of significant interest because of their vast potential applications in electroluminescent devices/displays and sensors. Herein, a novel bi-component supramolecular aggregation-induced emission (AIE) hydrogel (PDG) was successfully prepared with p-hydroxybenzonic acid-functionalized pillar[5]arene (SPA) and tri-(pyridine-4-yl)-functionalized trimesic amide (DTB) by a simple host–guest assembly process. The most attractive feature of PDG is its practical white-light-emitting property, which can be used for ultrasensitive detection and separation of Pb²⁺, Cr³⁺, and Fe³⁺ ions. The limits of lowest detection (LODs) of PDG for Pb²⁺, Cr³⁺, and Fe³⁺ are approximately 6.74 × 10⁻⁹, 7.18 × 10⁻⁹, and 8.25 × 10⁻⁹ M, respectively. Strikingly, by rationally introducing these metal ions into the PDG, a series of metal-ion-coordinated supramolecular metallogels PDG-Cr and PDG-Fe was constructed, and these metallogels can selectively detect CN⁻ and H₂PO₄⁻, respectively. The LODs of PDG-Cr and PDG-Fe for CN⁻ and H₂PO₄⁻ reached up to 10⁻⁸ M. The prepared PDG-based thin films can act as a smart fluorescent display material and test kit. The xerogel of PDG can adsorb and separate Pb²⁺, Cr³⁺, and Fe³⁺ from aqueous solution, with adsorption rates ranging from 96.73% to 98.95%.