Neptunium(V) complexation by natural pyoverdins and related model compounds

作者：Moll H^*; Glorius M; Johnsson A; Schaefer M; Budzikiewicz H; Pedersen K; Bernhard G

来源：Radiochimica Acta, 2010, 98(9-11): 571-576.

DOI：10.1524/ract.2010.1755

• Neptunium(V)
• Pyoverdin
• Hydroxamic acids
• Dihydroxynaphthalene
• NIR absorption spectroscopy
• Complexation

Ubiquitous fluorescent Pseudomonas species secrete bacterial pyoverdin-type siderophores. These bioligands have great potential to bind and transport actinides in the environment due to their hydroxamate and catechol functionalities. We investigated the unknown interaction of the neptunyl cation (NpO(2)(+)) with pyoverdins (PYO) released by Pseudomonas fluorescens (CCUG 32456) cells and with simple hydroxamate (salicylhydroxamic acid: SHA and benzohydroxamic acid: BHA) and catechol (2,3-dihydroxynaphthalene: NAP) ligands using near-infrared (NIR) absorption spectroscopy over a wide pH range. NpO(2)(+)-bioligand species of the M(x)L(y)H(z) type were identified from the spectrophotometric titrations in all four systems. The 1 : 1 : 2, 1 : 1 : 1, and 1 : 1 : 0 complexes were determined with the pyoverdins. In addition to 1: 1 species, SHA, BHA, and NAP also form 1: 2 : 0 species with NpO(2)(+). The stability constants of these neptunyl(V)-bioligand complexes and their individual spectroscopic properties are reported. Our findings indicate that NpO(2)(+) has a stronger affinity to the catechol functionality of the pyoverdin molecule. The identified NpO(2)(+)-PYO species belong to the strongest NpO(2)(+) complexes with organic material reported so far.

• 出版日期2010