Česká společnost pro hmotnostní spektrometrii

(5. konference České společnosti pro hmotnostní spektrometrii - ThO-005)
Comparative study of UO₂²⁺ and Fe³⁺ complexation with hydroxamate siderophore

Thibault Terencio ¹, Jana Roithová ^1 *, Michel Meyer ², Jean-Claude Chambron ²

1. Department of Organic Chemistry, Faculty of Science, Charles University in Prague
2. Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB)

Abstrakt

Among actinides, uranium is particularly wide-spread because of its use in nuclear industry. Uranium can contaminate sea water, soils, or rivers from abandoned mines [1]. Related to this problem, complexation of uranium gained increasing interest in order to separate uranium, from neptunium and plutonium, during treatment of nuclear fuel.

Hydroxamate ligands represent one category of siderophores. Their high affinity for Fe(III) makes them particularly suitable in biological applications. It was shown that siderophores can also bind to other metal ions[2]. thus highlighting their advantage in solving environmental issues such as water pollution by heavy metals. Actinides are also known to establish strong bonds with oxygen atoms, thus, it has been suggested that siderophores can favorably bind to actinides [3].

The main objective of this work is to show to which extent the complexation of uranyl (UO₂²⁺) and iron with a model hydroxamate (N-methylacetohydroxamate) is similar. In order to gain a deeper insight into the interactions between the metals and the hydroxamate, a combination of both theoretical calculations (DFT) and experimental data (IRMPD, mass, CID) was conducted.

Comparison between IRMPD and theoretical IR spectra allows us to propose structures for uranium and iron complexes. The results show that both complexations are similarly of covalent nature with a strong ionic character, with a slightly stronger ionic character in uranium complexes. While the bonding between the metals and the ligand is similar, the unimolecular reactivity at elevated collision energies in the dissociation experiments differ. The uranium complex shows a specific reactivity of the uranyl group with hydroxamate leading to a water loss.

* Korespondující autor: jana.roithova@natur.cuni.cz

Literatura

1. Dias da Cunha K. M. et al.: Environ. Geochem. Health 36 (3), 477–487 (2014).
2. Ducháčková L. et al.: Chem. - A Eur. J. 15 (48), 13399–13405 (2009).
3. Raymond K. N. et al.: Inorganica Chim. Acta 94 (4), 193–204 (1984).