Tuning the fluorescence sensing for Fe3+ ions by using different dipyridyl linkers in pillar-layered metal–organic frameworks

Abstract

Isostructural, pillar-layered metal–organic frameworks (MOFs) will provide an ideal structural model for studying the influence of functional groups on fluorescence sensing. Here, we study dipyridyl linkers to tune the detection of Fe³⁺ ions. Three isostructural analogues of pillar-layered frameworks were used as fluorescence sensors to quickly, sensitively, and selectively detect Fe³⁺ ions with good repeatability. Importantly, an increase in length of the pillars and accessible volumes may lead to an increase in the fluorescence quenching constants (K_sv(PL-1) = 1.58 × 10⁴ M⁻¹) < (K_sv(PL-2) = 1.72 × 10⁴ M⁻¹) < (K_sv(PL-3) = 2.47 × 10⁴ M⁻¹), which may be related to different dipyridyl ligands acting as pillars.