Synthesis and characterization of two new tetrapyrazolic macrocycles for the selective extraction of cesium cation

The synthesis of two macrocycles containing two bipyrazolic subunits, with different side arms is reported. These structures were characterised by 1H NMR, 13C NMR, mass spectroscopy and elemental analysis. The macrocycle bearing a hydroxyl group in the side arms, crystallizes in triclinic (S.G.: P-1) systems, with the unit cell parameters: [11.3086(4), 13.6865(5), 14.6311(5), 108.774(3), 105.408(3), 107.131(3), V=1879.28(15) Å3]. It possesses 3D crystal structure with molecules interacting through weak H-bonds. The complexing properties of new macrocycles towards alkaline metal ions (Li+, Na+, K+ and Cs+) were studied by a liquid–liquid extraction process. The percentage values of extraction were determined by atomic absorption measurements and UV spectroscopy. Their macrocyclic cavities are better adapted to extract the Cs+ cation. The macrocycle with side chains bearing donor groups shows the best extraction due to its participation in complexation.

Figure optionsDownload high-quality image (162 K)Download as PowerPoint slide