New Chelating Ligands with Potential for Pharmaceutical Applications
摘要:
2-hydroxybenzylaminomethylphosphonic acid (HBAMPA) has been synthesized from commercially available chemicals and its aqueous coordination chemistry involving Al3 +, Ga3 + and Fe3 + is described. At 25 degrees C and 0.1 M ionic strength KNO3, both Al3 + and Ga3 + formed dinuclear complexes while Fe3 + formed the simple 1:1 complex (FeL) along with a mono-protonated complex (FeLH). HBAMPA formed neutral complexes with these trivalent metal ions, which lead to an early precipitation. The solution mixtures precipitated at pH 6.0 for Al3 +, pH 4.0 for Fe3 +, and pH 3.0 for the Ga3 + ion. The carboxylic acid analogue of HBAMPA, 2-hydroxybenzylalanine (HBA) also has been tested with Al3 + and Fe3 +. It appeared that HBA solubilized the Al3 + ion at pH 7.4. However, the Fe3 +-HBA solution mixture formed a complex of a very minimum solubility and an early pH precipitation prevailed. HBA and HBAMPA are multi-dentate, phenol-containing ligands capable of binding a variety of metal ions with very high stability constants. These stability constants are discussed.