Preparation and investigation of Ce(III), Th(IV) and U(VI) chelates with some Schiff bases derived from 5,7-dihydroxy-6-formyl-2-methylbenzopyran-4-one

摘要

Schiff bases were prepared by condensation ofequimolar amounts of 5,7-dihydroxy-6-formyl-2-methylbenzopyran-4-one and aniline, anthranilic acid, 2-aminophenol, 5-chloro-2-aminophenol or 4-amino-3-hydroxybenzenesulphonic acid. The molecular structure of theprepared Schiff bases was confirmed by mass and UV spectra. Thechelates of Ce (III), Th (IV), and U (VI) with the above Schiffbases were prepared. All the prepared compounds were bubjectedto elemental analyses for C, H, N, Cl, S and metal (for thechelates), IR and 1H NMR spectroscopy. The studies show that Ce(III) and Th (IV) give 1:1, 1:2 (M: L) metal chelates, while U (VI)gives only 1:1 and 1:2 (M:L) chelates. This may be attributed tothe difficulty of coordinating two bulky uranyl ions to the samemolecule because of their steric effect. The studies revealed thatthe Ce (III) and Th (IV) chelates exhibit octahedral structure withthe coordination number 6 while U (VI) chelates exhibitdodecahedral structure with the coordination number 8.Thermogravimetric analysis data were obtained for some of theprepared chelates.