SYNTHESIS AND LUMINESCENCE OF EU3+ AND TB3+ COMPLEXES WITH NOVEL CALIX[4]ARENE LIGANDS CARRYING 2,2'-BIPYRIDINE SUBUNITS

Eu3+ and Tb3+ complexes with novel branched cali[4]arene ligands incorporating 2,2'-bipyridine subunits functionalized in the 6- or 5,5'-positions have been synthesized and their photophysical properties investigated. High luminescence intensity was obtained for the Eu3+ complex of the calix[4]arene ligand carrying four 5,5'-substituted-2,2'-bipyridines, which has high molar extinction coefficients (epsilon(max) = 39 600 M(-1) cm(-1)) and a high luminescence quantum yield (15%).