LANTHANIDE COMPLEXES OF POLYACID LIGANDS DERIVED FROM 2,6-BIS(PYRAZOL-1-YL)PYRIDINE, PYRAZINE, AND 6,6'-BIS(PYRAZOL-1-YL)-2,2'-BIPYRIDINE -SYNTHESIS AND LUMINESCENCE PROPERTIES

The synthesis of three novel pyrazole-containing complexing acids, yl) pyrazol-1-yl]-4-methoxypyridine}tetrakis{acetic acid) (1), (aminomethy l)pyrazo-1-yl]pyrazine}-tetrakis(acetic acid) (2), and thyl)pyrazol-1- yl]-2,2'-bipyridine}tetrakis(acetic acid) (3) is described. Ligands 1- 3 formed stable complexes with Eu-III, Tb-III, Sm-III, and Dy-III in H 2O whose relative luminescence yields, tripler-state energies, and emi ssion decay lifetimes were measured. The number of H2O molecules in th e first coordination sphere of the lanthanide ion were also determined . Comparison of data from the Eu-III and Tb-III complexes of 1-3 and t hose of the parent trisheterocycle (aminomethyl)pyrazol-l-yl]pyridine} tetrakis(acetic acid) showed that the modification of the pyridine rin g for pyrazine or 2,2'- bipyridine strongly modify the luminescence pr operties of the complexes. MeO Substitution at C(4) of 1 maintain the excellent properties described for the parent compound and give an add itional functional group that will serve for attaching the label to bi omolecules in bioaffinity applications.