C. Galaup et al., Time-resolved luminescence in aqueous solution - New europium labels derived from macro(bi)cyclic ligands with aminocarboxylic units, EUR J ORG C, (11), 2001, pp. 2165-2175
A new family of macro(bi)cyclic ligands has been designed and synthesized,
with the goal of developing lanthanide labels suitable for time-resolved lu
minescence-based biological applications. They are constructed from diamide
(3) or tetralactam (4) complexing moieties associated with an intracyclic
2,2'-bipyridine chromophore and two exocyclic carboxylic groups. The lumine
scence properties of their Eu3+ complexes were studied in aqueous solution.
In this medium, noticeable enhancements in the lifetime and quantum yield
were observed, in comparison with those of other bipyridine-based ligands c
onsidered interesting as luminescent labels. The effects of coordinated wat
er molecules, LMCT states, and ligand triplet state energy on the nonradiat
ive deactivation processes to the ground state were examined. According to
these results and in view of the stability of these complexes in aqueous so
lutions, the (Eu(3)](+) complex may be considered as a promising luminescen
t bioprobe.