Pore-space-partitioned metal–organic frameworks for sensitive and selective recognition of 2,4,6-trinitrophenol

Abstract

Metal–organic frameworks (MOFs) constructed via the pore space partition (PSP) strategy can exhibit precisely tailored pore environments. In this work, a series of MOFs (SNNU-290 to SNNU-293) were rationally designed and synthesized using PSP to enable highly specific and efficient detection of 2,4,6-trinitrophenol (TNP). Comparative studies on various nitroaromatic explosives (NAEs) unambiguously confirmed that the PSP strategy is pivotal for endowing these MOFs with exceptional specificity and sensitivity toward TNP. Among them, SNNU-293 demonstrated outstanding performance in both liquid- and gas-phase detection, particularly excelling in gas–solid sensing with remarkable optical stability, excellent cycling durability, and distinct visualization capabilities for TNP vapor. Mechanistic investigations, combining experimental and theoretical approaches, revealed that the fluorescence quenching of TNP is primarily governed by two synergistic pathways: photoinduced electron transfer (PET) and competitive absorption (CA). This study not only provides fundamental insights into the application of novel MOFs in environmental monitoring and security sensing but also underscores the critical role of PSP in advancing target-specific sensing systems. Furthermore, it highlights the substantial potential of SNNU-293 as a high-performance sensor material for practical TNP detection.