SPECTROSCOPIC CHARACTERIZATION OF ETHYLENEDIAMINEDI(O-HYDROXYPHENYL)ACETIC ACID AND ITS COMPLEXES WITH LANTHANIDE(III) IONS

Binding properties of ethylenediaminedi(o-hydroxyphenyl)acetic acid (E HPG) with lanthanide(III) ions were studied using spectroscopic method s. Luminescence intensity and lifetime of the Tb(III) ion were measure d in a wide pH range in order to characterized the Ln-EHPG complexatio n. The calculated hydration number of the Tb-EHPG system proved the re placement of six water molecules by the EHPG ligand in the inner co-or dination sphere of Tb(III). Energy transfer from Tb(III) to Eu(III) in the Tb(III)-EIIPG-Eu(III) system indicated an existence of only monom eric form of the Tb-EHPG complex. Analysis of the H-1 NMR and FTIR spe ctra of the EHPG ligand and its complexes with lanthanide(III) ions co nfirmed the hexadentate manner of EHPG complexation with the lanthanid es. The system of Dh(III)-EIIPG, showing a linear dependence of lumine scence intensity (lambda(em)=578 nm) of Dy(III) on its concentration, in the range of 3.3x10(-7) to 1x10(-5) mol . l(-1), can be applied for spectrofluorimetric determination of Dy(III).