Sonochemically synthesized microporous metal-organic framework representing unique selectivity for detection of Fe3+ ions

Synthesis of metal-organic framework (MOF) materials via ultrasound (US) irradiation involves shorter reaction times and offers enhanced control of particle size and morphology compared to conventional electric heating. Here, we report the exploration of highly luminescent three-dimensional microporous metal-organic framework, [Zn-2(oba)(2)(bpy)], (1; H(2)oba = 4,4'-oxybis(benzoicacid); bpy = 4,4'-bipyridine) synthesized by sonochemistry for highly selective and sensitive detection of Fe3+ in MeOH solution via a fluorescence quenching mechanism. Fluorescence titration experiments reveal that 1 is highly selective for Fe3+ ion with a response time of <2 min and the limit of detection (LOD) reaches a low level of 0.3 mu M (17 ppb). The luminescence is completely quenched in 100 mu M MeOH solution of Fe3+. Furthermore, the static quenching constant is calculated to be upper than 58 000 M-1 by the fluorescence titration experiment in low concentration of Fe3+. No interferences from 250 mu M As3+, Cd2+, Zn2+, Co2+, Ni2+, Cu2+, Pb2+, Mn2+ and Al3+ were found for the detection of Fe3+. Importantly, 1 can be cycled at least four times without loss of emission signals, which suggests that the functionalized 1 is a promising luminescent probe for selectively sensing of Fe3+ ions. (C) 2018 Elsevier Ltd. All rights reserved.