A novel supramolecular polymer gel based on naphthalimide functionalized-pillar[5]arene for the fluorescence detection of Hg2+ and I− and recyclable removal of Hg2+via cation–π interactions

Abstract

The development of novel materials for the detection and removal of Hg²⁺ is a very important issue due to the acute toxicity of Hg²⁺. Herein, a novel supramolecular polymer P5BD–DPHB has been constructed by the collaboration of a naphthalimide functionalized-pillar[5]arene host (P5BD) and a bis-bromohexane functionalized-pillar[5]arene guest (DPHB). P5BD–DPHB could form a stable supramolecular gel (P5BD–DPHB–G). Interestingly, P5BD–DPHB–G shows selective fluorescent “turn-on” detection for Hg²⁺via cation–π interactions with high selectivity and sensitivity. Furthermore, the Hg²⁺ coordinated supramolecular gel P5BD–DPHB–HgG can detect I⁻ successively. The detection limits for Hg²⁺ and I⁻ are 1.65 × 10⁻⁹ and 1.84 × 10⁻⁸ mol L⁻¹, respectively. Even more significantly, the xerogel of P5BD–DPHB–G could remove Hg²⁺ from aqueous solution with excellent recyclability and ingestion capacity, and with a Hg²⁺ removal rate of 98%.