Luminescent metal organic frameworks (LMOFs) and allied composites for the unveiling of organic environmental contaminants (explosive NACs, PAHs and EDCs) sensing through ‘Molecular Recognition’: A chronicle of recent penetration and future modelling

Abstract

The class of functional materials centralized on luminescent metal–organic frameworks (LMOFs) has recently been at the forefront of optical sensing. LMOFs exhibit fascinating luminescence properties, functional diversities, and dynamic participation in supramolecular interactions, making these materials highly promising for ‘molecular recognition’ purposes. Interestingly, LMOFs can be deliberately downsized to nano-realm to construct nano-structured LMOFs or LMOF-nanosheets with enhanced surface properties, including interface-driven toxic analyte recognition. Besides, by adaptation of suitable synthesis routes, LMOF-composites (MOF@Lanthanides, MOF@polymers, Dye@MOFs, etc.) with enhanced stability, fluorescence properties, and new morphological features may be produced. This review article critically discusses the progression of LMOFs and allied materials toward effective monitoring of organic environmental contaminants (OECs) in the last few years (2018–2023). As OECs, we focus here on three categories: (a) explosive nitroaromatic compounds (NACs), (b) polycyclic aromatic hydrocarbons (PAHs), and (iii) endocrine-disrupting chemicals (EDCs). In the current situation, mutagenic NACs are employed profusely in terrorist activities and as a precursor to several industrially essential processes. Further, unrestricted industrialization has contributed noticeably to the emission of carcinogenic PAHs in air, soil, and water. Additionally, certain emerging chemicals, including pesticides, bisphenols, dioxins, antibiotics, polychlorinated biphenyls, etc., can cause severe harm to endocrine functions when they reach the human body. All these factors motivated us to present such a review article that is still scanty in its congeners but has an enormous impact on today’s scientific community. The article has been systematically divided into distinct sections. For example, popular design strategies (solvothermal, top-down and bottom-up approaches, exfoliation, interface-driven techniques, etc.) are discussed in Section 2. The features of linker-based luminescence, antenna effect, charge transfer, energy, and electron transfer pathways are presented in Section 3. The ligand design strategy, performance in bulk and nano-scale, detection sensitivity, and other relevant analytical results are also provided in detail. Moreover, we present a future perspective for the possible integration of artificial intelligence (AI) and machine learning (ML) approaches with LMOF-based next-generation materials for better quantification of toxic analytes.