Novel pillar[5]arene-based supramolecular organic framework gel for ultrasensitive response Fe3+ and F- in water

Abstract

A novel supramolecular organic framework gel (PQPA) has been constructed by a novel bilateral 8-hydroxyquinoline modified pillar[5]arene host (P5Q) and a bilateral bromohexyl functionalized pillar[5]arene guest (P5C6). Interestingly, the gel PQPA shows special selective and ultrasensitive sensing property for Fe³⁺. The limit of lowest detection (LOD) of gel PQPA for Fe³⁺ is 0.102 nM. Meanwhile, by adding Fe³⁺ into the gel PQPA, a no fluorescence Fe³⁺ coordinated metallogel (PQPA-Fe) could be constructed. Due to the competitive coordination of F^-, fluorescent "turn-on" ultrasensitive response of the Fe³⁺ coordinated metallogel (PQPA-Fe) for F^- is achieved. The limit of lowest detection of the Fe³⁺ coordinated metallogel (PQPA-Fe) for F^- is 9.79 nM. In addition, the xerogel of the supramolecular organic framework gel (PQPA) is capable for removing Fe³⁺ in a lower concentration aqueous solution at an adsorption rate of 99.9%. More importantly, the supramolecular organic framework gel (PQPA) could be used to detect Fe³⁺ in the Yellow River Water samples. The supramolecular organic framework gel (PQPA) and Fe³⁺ coordinated metallogel (PQPA-Fe) could act as ultrasensitive reversible fluorescent chemosensor, test kits and fluorescent display materials for Fe³⁺ and F^-.

Keywords: Effective removal; Fluoride anion; Iron (III) ion; Supramolecular organic framework gel; Ultrasensitive detection.