A dual-response regenerable luminescent 2D-MOF for nitroaromatic sensing via target-modulation of active interaction sites

Abstract

Sensitive detection of nitroaromatic compounds is of urgent need due to serious environmental concerns. Surface modulation is a remarkable approach to alter the accessibility of the active interaction sites within MOF scaffolds to provide specific host–guest interactions for advanced practical purposes. To achieve this goal, a 2D-MOF, namely TMU-58, with highly accessible urea interaction sites (–NH–CO–NH–) was judiciously selected. Ultrasound irradiation and modulation synthesis were also used to obtain various sizes and morphologies of TMU-58, namely US-TMU-58 and M-TMU-58, respectively. Remarkably, the quenching studies towards nitrobenzene (NB) and trinitrophenol (TNP) analytes revealed that the detection ability is highly related to the accessibility of –NH or –CO interaction sites on the surfaces of the 2D-MOF. TMU-58 with a rod-shape morphology interacts selectively with nitrobenzene based on the formation of strong hydrogen bonds via –NH functional sites (K_sv = 4 × 10³ M⁻¹, LOD = 87 μM), while M-TMU-58 with a plate-like morphology interacts selectively with TNP owing to the abundant accessible –CO functional sites on the surfaces (K_sv = 9.36 × 10⁴ M⁻¹, LOD = 6 μM). These results revealed that the facile and effective targeted design strategies will highlight a roadmap to achieve promising performance in practical application.