STUDY OF THE URANYL ION INTERACTION WITH 3-HYDROXYMETHYL-1,2,4-TRIAZOLYLACETIC ACID ESTERS

UDC 546.791.6-381+547.792.4

Abstract

The synthesis of new derivatives of 3-hydroxymethyl-1,2,4-tryazolylacetic acids were described as well as the products of their interaction with uranyl ion. It was shown that 3-hydroxymethyl-1,2,4-triazolylacetic acid esters undergo an hydrolysis in the presence of uranyl ions and form the uranyl complexes with corresponding acids. The composition and structure of obtained compounds were determinated by IR and ¹H NMR spectroscopy and elemental analysis. Complexes [UO₂(HL^1')(CH₃OH)]₂ and [UO₂(H₂L^2')]₂(CH₃OH) have dinuclear structure and are stable in DMSO solution. The triazole nitrogen, the oxygen of carboxyl group and the hydroxymethyl oxygen take part in bond formation between uranyl ions and organic ligands. The disappearance in the IR spectra intense band ν(C=O) from esters at 1710-1717 cm^-1, and the appearance of the intensive stretching vibration bands ν_as(COO^-) from carboxylic acids at 1590-1608 cm^-1 confirmed formation of complexes with acids H₂L^1' and H₃L^2' . In the spectra of the complexes an intense absorption band of ν(C-O) of hydroxymethyl fragment shifts in the low-frequency field from 1060-1071 cm^-1 to 1021-1057 cm^-1, that is typical for coordinated hydroxyl group. Furthermore in the spectra of the complexes the band ν(O-H) at 3485 cm^-1 disappears indicating the deprotonation of the hydroxyl group. The scheme of the interaction between the esters H₂L¹ and H₃L² and uranyl ion was proposed. In the reaction mixture acetate ions act as acceptors of protons of hydroxyl groups of mononuclear complex particles, helping to create binuclear complexes.