New sensitizer-modified calix[4]arenes enabling near-UV excitation of complexed luminescent lanthanide ions

Article abstract of DOI:10.1021/ja00142a004

The synthesis is described of a series of calix[4]arenes with three different sensitizer chromophores ("antenna") attached to the lower rim via a short spacer. In the Eu³⁺ and Tb³⁺ complexes of these calixarenes, 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 case of Eu³⁺, especially a triphenylene antenna is found to have strong sensitizing ability toward not only Eu³⁺ but also Tb³⁺, allowing excitation of the lanthanide with wavelengths extending to 350 nm.