Spectroscopic Studies of Uranyl Solution Phase Complexation by Short Chain β-Hydroxy Carboxylic Acids

Abstract

The interactions between 3-hydroxybutyric and 3-hydroxypropanoic acid and uranyl have been studied by 1H and 13C NMR and UV-vis spectroscopy as a function of pH. The NMR data suggest that binding occurs at relatively low pH, between 3 and 5, and that only the carboxylic part of each ligand is involved in direct binding. The results indicate that the alcohol groups in each ligand do not participate in bonding as the nuclei in the vicinity of the OH groups do not experience a significant change in their chemical shift upon complexation. The NMR data indicate that a maximum of 3 ligands will coordinate around the uranyl metal centre for 3-hydroxybutyric acid. 3-Hydroxypropanoic did not exhibit the same characteristics as that seen for 3-hydroxybutyric. It was found to bind only an average of two ligands to uranyl, compared with three for 3-hydroxybutyric, and complexes formed around a narrower pH range. Comparison of the results of this study with literature data shows that gluconate and ISA form much stronger complexes with uranyl, as they holds it in solution across a much broader pH range. Although, 3-hydroxybutyric and 3-hydroxypropanoic acid contain the same binding site as gluconate, it has been shown that they have radically different interactions with uranyl.

Date of Award	1 Aug 2011
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Nicholas Bryan (Supervisor)