Mj. Remuinan et al., SYNTHESIS AND LUMINESCENCE PROPERTIES OF EUROPIUM(III) AND TERBIUM(III) COMPLEXES WITH POLYACID CHELATES DERIVED FROM 2,6-BIS(N-PYRAZOLYL)PYRIDINE, Perkin transactions. 2, (6), 1993, pp. 1099-1102
A short and efficient synthesis of -aminomethyl-1-pyrazolyl)pyridine]-
tetrakis(acetic acid) (6), an analogue of terpyridine with additional
chelating iminodiacetic groups, is described. Compound 6 forms stable
complexes with Eu(III) and Tb(III) in water whose relative luminescenc
e yields, excitation maxima and emission decay lifetimes have been mea
sured. The number of water molecules in the first coordination sphere
of the europium complex have also been determined. Comparison of data
from the Eu(III) and Tb(III) complexes of 6 and of the parent trishete
rocycle diacid 2,6-bis(3-carboxy- 1 -pyrazolyl) pyridine shows that th
e iminodiacetic subunits give extra stabilization to the complexes and
are essential to protect the metal from the water environment.