STRUCTURE AND SPECTRAL-LUMUINESCENT PROPERTIES OF LANTHANIDE-CONTAINING COMPLEXES WITH AZACROWN CALIXARENES

Abstract

Lanthanide complexes with calix[4]arenes lower rim substituted with two azacrown ether fragments are reported. The size of the substituent cavity varied from 4 to 6 heteroatoms. The complexes were analyzed by means of IR, NMR, ESI mass spectroscopy. It is assumed that the coordination of Ln(III) ions occurs through the donor atoms of the lower rim; the counter anion and solvent molecule are also coordinated. Lanthanide-centered characteristic luminescence was observed in Eu(III), Tb(III) and Yb(III) complexes. The most efficient 4f-luminescence is observed for terbium-containing complexes with benzo-crown-derived ligands. The pathways of the sensitization of 4f-luminescence are discussed.