Article

Complexation of Np<sup>V</sup> Ions with 1,10‐Phenanthroline‐2,9‐dicarboxylic Acid: Spectrophotometric and Microcalorimetric Studies

Yanqiu YangChemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA, http://https://commons.lbl.gov/display/csd/Linfeng+RaoZhicheng ZhangChemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA, http://https://commons.lbl.gov/display/csd/Linfeng+RaoShunzhong LuoInstitute of Nuclear Physics and Chemistry, Chinese Academy of Engineering Physics, Mianyang, Sichuan 621900, ChinaLinfeng RaoChemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA, http://https://commons.lbl.gov/display/csd/Linfeng+Rao

2014en

ABI

Abstract

Abstract The complexation of Np V ions with a tetradentate ligand with oxygen and nitrogen donors, 1,10‐phenanthroline‐2,9‐dicarboxylic acid (denoted as H 2 L), was studied in aqueous solutions by spectrophotometric and calorimetric methods. Np V ions form a very strong 1:1 complex, NpO 2 L – , with the stability constant log β = 11.73 ± 0.02 in 0.1 M NaClO 4 at 25 °C. It is a much stronger complex than those of Np V ions with related ligands such as picolinic acid or dipicolinic acid, as the higher denticity of 1,10‐phenanthroline‐2,9‐dicarboxylic acid results in a larger entropic effect on the complexation. It is expected that the amide derivatives of 1,10‐phenanthroline‐2,9‐dicarboxylic acid would be excellent extractants in the separation of Np V ions, which are problematic in actinide separation processes owing to their very low extractability by many extractants.

Identifiers

DOI: 10.1002/ejic.201402520

Citations and references

Cited by 20 references

Metrics — AkademScholar