PHOTOLUMINESCENCE OF THE EUROPIUM(III) AND TERBIUM(III) HOMODINUCLEAR POLYMERIC TETRAAZAMACROCYCLIC COMPOUNDS

Abstract

The photoluminescence properties of the new [Eu₂(16-ANE-N₄)(NO₃)₃ (CHO₂)₃]₇ (1) and [Tb₂ (16-ANE-N₄)(NO₃)₃(CHO₂)₃CH ₂O₂]₇ (2) compounds at 300 and 20 K show the characteristic fluorescence spectra of the Eu(III) and Tb(III) ions and an intrinsic emission when the samples are excited at 395 and 370 nm, respectively using a xenon lamp. The observed intrinsic emission of these complexes indicates a similar environment around the metals and evidence of the nature of these polymers. The luminescence lifetimes were found to be 1.74 and 2.94 μs for the ⁵D₀ → ⁷F₂ (Eu(III)) and ⁵D₄ → ⁷F₅ (Tb(III)) transitions, respectively at 300K. To our knowledge, these are the shortest lifetimes measured for Eu(III) and Tb(III) complexes so far. Both the fluorescence spectra and the luminescence lifetimes of these complexes suggest an isostructural nature of these homodinuclear polymeric compounds.

Key Words:

• Emission
• excitation
• intrinsic emission
• luminescence lifetime
• tetraazacyclohexadecane ligand
• homodinuclear lanthanide(III) polymeric compounds