The coordination of low-valent Re/Tc with glutarimide dioxime and the fate of Tc in aqueous solution: spectroscopy, ESI–MS and EXAFS

The effect of glutarimide dioxime (H3A) on the fate of Tc in aqueous solution was studied, the results found that the distribution ratio of Tc between TBP and aqueous phase decreased by one order of magnitude with addition of H3A, due to the formation of low-valent Tc complexes with H3A. Further study of coordination mode between low-valent Tc and H3A was carried by using Re as substitute. Firstly, the low-valent Re complexes with H3A were prepared by reduction of Re(VII) using hydrazine in the presence of H3A, the results showed that pH 8.0, high CH3A and high Chydrazine are favorable for the formation of low-valent Re complexes, with a characteristic peak at 380 nm. Subsequently, the species of low-valent Re complexes were further studied by XPS, ESI–MS and EXAFS, low-valent Re is tetravalent and forms 1:1 (ReA) and 1:2 (ReA2) mononuclear complexes with H3A. The low-valent Re/Tc complexes are air-stable in aqueous solution.