Stability constants of europium complexes with a nitrogen heterocycle substituted methane-1,1-diphosphonic acid

Conference · Sat Jun 01 04:00:00 EDT 1996

OSTI ID:242692

Jensen, M P; Rickert, P G; Schmidt, M A; Nash, K L

Even in moderately acidic solutions ([H{sup +}] > 0.01 M), N-piperidinomethane-1,1-diphosphonic acid (H{sub 4}PMDPA) is a strong complexant of trivalent lanthanide ions that shows enhanced complex solubility over previously studied 1,1-diphosphonic acids. The protonation constants of PMDPA in 2.0 M H/NaClO{sub 4} were determined by potentiometric and NMR titrations, and the stability constants for formation of complexes with Eu{sup 3+} were determined by solvent extraction. Difference in protonation equilibria induced by addition of the nitrogen heterocycle results in an increase in the complexation strength of PMDPA. In solutions containing 0.1 M H{sup +} and ligand concentrations greater than 0.02 M, PMDPA is the most effective 1,1-diphosphonic acid for europium complexation studied thus far.

• Research Organization: Argonne National Lab., IL (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 242692
• Report Number(s): ANL/CHM/CP--89020; CONF-960796--3; ON: DE96011158
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
EUROPIUM COMPLEXES
EUROPIUM IONS
PHOSPHONIC ACIDS
SOLVENT EXTRACTION