Recent advancements in encapsulation of poly aromatic hydrocarbons via macrocyclic host-guest chemistry

Polyaromatic hydrocarbons (PAHs) pose a significant threat to ecosystems and human health due to their widespread presence and persistence in the environment. Conventional remediation techniques often fall short in both efficiency and environmental impact. However, recent advancements in utilizing organic macrocyclic host molecules show considerable promise for effectively sequestering and eliminating PAHs across diverse media. These macrocyclic host molecules play a central role in host–guest chemistry and supramolecular chemistry. It offers distinct advantages by virtue of their precisely tailored cavities and customizable functionalities, greatly enhancing their selective recognition abilities towards guest PAHs. The pursuit of designing and synthesizing novel functional macrocycles has captivated the attention of researchers, driven by the quest to address various challenges in supramolecular research. Over decades of dedicated exploration in host–guest chemistry and supramolecular chemistry, an expansive array of macrocyclic host molecules, constructed from diverse building blocks, have emerged as pivotal tools for encapsulating PAHs. This review presents an overview of the recent progress in the design, synthesis, and application of purely organic macrocyclic molecules in the encapsulation of PAHs. It elucidates the underlying principles that govern their ability to recognise PAHs, such as host–guest interactions, shape complementarity, and π-π stacking interactions. Furthermore, the review discusses various experimental methodologies, such as spectroscopic analyses, chromatography, and computational modelling, employed to assess the efficiency of organic cage molecules in PAH trapping. Additionally, considerations regarding the scalability and environmental implications of organic cage-based PAH trapping systems are addressed. The insights gleaned from this research provide valuable guidance for the development of robust strategies to combat PAH pollution in diverse environmental contexts.