Synthesis of calix[4]arene receptors incorporating (2,2'-bipyridin-6-yl)methyl and (9-methyl-1,10-phenanthrolin-2-yl)methyl chromophores and luminescence of their Eu3+ and Tb3+ complexes

Several new calix[4] arene derivatives in the cone conformation 3-5 and 8-11, incorporating 2,2'-bipyridine or 1,10-phenanthroline chromophores have been synthesized in order to Obtain luminescent complexes with EU(3+) and Tb3+. Whereas phenanthroline containing ligands 10 and 11 gave no indication of complex formation with lanthanide ions, the ligand 3 incorporating four 2,2'-bipyridine chromophores and the ligands 8 and 9, bearing two amide and two 2,2'-bipyridine groups, were able to sensitize EU(3+) and Tb3+ luminescence, The Tb3+ complex of compound 9 showed intense metal luminescence thanks to the high values of the molar absorption coefficient (epsilon = 29000 dm(3) mol(-1) cm(-1)) and quantum yield (phi = 0.12).