Two-step Synthesis of a New Twenty-Membered Macrocycle: Spectroscopic Characterization and Theoretical Calculations

A highly symmetrical substituted macrocycle was designed, synthesized and characterized as a novel supramolecular scaffold, whose structure was unequivocally characterized by H-1, C-13, COSY, HMBC, HMQC and DOSY NMR, UV-Vis, FTIR spectroscopy and mass spectrometry. With its defined and electron-rich aromatic cavity, this macrocycle could be a potential host for inorganic and organic cations. Preliminary investigations on the coordinating abilities of the studied macrocycle show a noticeable interaction between the obtained product and Pb2+ ions. These interactions have been highlighted by mass spectrometry, UV-Vis spectroscopy, and supported by DFT and TD-DFT modelling, making this new macrocycle an interesting candidate for possible heavy metal ions removal or for the design of artificial molecular machines. Good reaction yields, accessibility of reagents and absence of catalysts make this synthetic approach useful for systematic screening and up-scaling of a large number of compounds.