Synthetic Modifications of a Pb²⁺-Sensor Acridono-Crown Ether for Covalent Attachment and Their Effects on Selectivity

Because of environmental impact, there is a great need for chemosensors, especially for toxic heavy metals such as lead. The conventional instrumental analytical techniques rarely provide an available real-time sensing platform, thus the development of highly selective and stable synthetic chemosensor molecules is of great importance. Acridono-18-crown-6 ethers have such properties, and much research has proven their outstanding applicability in various supramolecular devices. In this present work, we aimed to enable their covalent immobilization capability by synthesizing functionalized derivatives while preserving the favored molecular recognition ability. Several new macrocycle analogues were synthesized, while synthetization difficulties and design aspects were also dealt with. The selectivity of the macrocycle analogues was studied using UV–Vis spectroscopy and compared with that of the parent compounds. The ultimate crown ether derivative showed high Pb2+-selectivity, reversibility (decomplexation by extraction with water) and stability.