Synergistic complexes of uranyl ion with 1-phenyl-3-methyl-4-acetyl-pyrazolone-5 and some oxo-donors

Abstract

Complexes of uranyl ion with 1-phenyl-3-methyl-4-acetyl-pyrazolone-5(PMAP) and various oxo-donors such as aliphatic sulphoxides [R 2SO, where R = i-C 5H 11(DISO), n-C 6H 13(DHSO), n-C 7H 15(DSSO), n-C 8H 17(DOSO), n-C 9H 19(DNSO), n-C 1OH 21(DDSO), n-C 11H 23(DUDSO) and n-C 4H 9(DBUSO)] tributylphosphate (TBP) and tri- n-octyl phosphine oxide (TOPO) have been synthesised and characterized. Analytical data establish that they have the stoichiometry UO 2(PMAP) 2X where X is the oxo-donor. The IR spectra of the sulphoxide complexes in the SO stretching region indicate that the ligands R 2SO are O-bonded. The methyl protons of the pyrazole ring and acetyl group in the PMAP ligand are equivalent giving rise to a single sharp peak in the PMR spectra, whereas in the synergistic complexes with the oxo-donors, two deshielded peaks of equal intensity are observed which indicate the non-equivalence of the methyl groups. The peak which is more deshielded has been ascribed to the methyl of the acetyl group. The higher deshielding of these methyl protons arises due to the transfer of electron density to the metal atom on complexation.