Résumé
Volatile organic compounds (VOCs), particularly benzene, pose significant threats to air quality, human health, and the environment. To address this concern, effective capture methods are essential. Metal-Organic Frameworks (MOFs) have emerged as promising materials due to their high surface area and tuneable adsorption properties [1]. This presentation aims to explore the reticular chemistry of MOFs by integrating experimental data and theoretical modelling. Specifically, the impact of metal ions and ligand aromaticity on benzene affinity within isostructural/isoreticular MOFs will be investigated in details. A thorough understanding of these fundamental aspects allows proposing relevant strategies for the design of MOF-based adsorbents for benzene capture, thereby contributing to improving air quality and human health. Two examples will be reported and discussed, highlighting respectively the impact of palladium as a metal node and the role of highly conjugated ligands (e.g. pyrene-like) for the efficient capture and detection of benzene. Despite the well-known affinity of palladium for rich π systems, research on Pd(II)-based MOFs for VOC capture remains limited. We have compared the adsorption properties of isostructural [Pd(2-pymo)2]n and [Cu(2-pymo)2]n, focusing on their selectivity for linear, cyclic, and aromatic VOCs [2]. We have demonstrated that [Pd(2-pymo)2]n exhibits a higher affinity for aromatic compounds than for saturated hydrocarbons, unlike [Cu(2-pymo)2]n. Additionally, [Pd(2-pymo)2]n exhibits preferential adsorption of benzene over toluene due to steric hindrance effects. Another computational study was carried out on a series of isoreticular IRMOFs (-1,-10,-14 and -16) to assess the effect of ligand aromaticity on the adsorption affinity for benzene and its non-aromatic analogue, cyclohexane [3]. We observed that while KH values decrease with elongation of the ligand (IRMOF-10, -16), insertion of a pyrene core (IRMOF-14) significantly increases the adsorption efficiency for both cyclohexane and benzene by ∼290% and 54%, respectively.