Fj. Steemers et al., NEW SENSITIZER-MODIFIED CALIX[4]ARENES ENABLING NEAR-UV EXCITATION OFCOMPLEXED LUMINESCENT LANTHANIDE IONS, Journal of the American Chemical Society, 117(37), 1995, pp. 9408-9414
The synthesis is described of a series of calix[4]arenes with three di
fferent sensitizer chromophores (''antenna'') attached to the lower ri
m via a short spacer. In the Eu3+ and Tb3+ complexes of these calixare
nes, photoexcitation of the antenna can induce lanthanide emission via
intramolecular energy transfer. Although the higher energy of the Tb3
+ luminescent state makes it more difficult to sensitize than in the c
ase of Eu3+, especially a triphenylene antenna is found to have strong
sensitizing ability toward not only Eu3+ but also Tb3+, allowing exci
tation of the lanthanide with wavelengths extending to 350 nm.