抄録
The acid dissociation constants and stability constants of metal chelates and protonated complexes of 2-aminoethylphosphonic acid (H2NCH2CH2PO3H2) and its related compounds (aminomethylphosphonic acid, 3-aminopropylphosphonic acid and O-phosphoethanolamine), were measured by potentiometry at 25° and μ=0.1 (NaClO4) in aqueous solution. The acid dissociation constants were compared with those of aminocarboxylic acids, aminosulfonic acids, and related compounds. The stability of complexes was in the order of Mn<Co<Ni<Cu>Zn, and these values were influenced by the ligand basicity and the chelate size. It was revealed that the stability constant (log KML) of aminophosphonic acids lay between those of glycine and adenosine triphosphate (ATP) and aminophosphonic acids showed comparatively low selectivity to bivalent metal ions used.
