Spectroscopic studies of the Eu(III) and Gd(III) tris(3-aminopyridine-2-carboxylic acid) complexes

The synthesis and spectroscopic studies of the complexes of Eu(III) and Gd(III) with 3-aminopyridine-2-carboxylic acid (3-NH(2)pic) are described. An experimental and theoretical analysis of the intensities of the D-5(0) --> F-7(0,1,2,4) transitions of the Eu(III) ion is presented. An approximate structure for the Eu(III) complex is assumed and the theoretical calculations are based on a model, previously described, which takes into account the forced electric dipole and dynamic coupling mechanisms.