Synthesis and Spectral Study of Several Solid M₃[Eu(2,6-Pyridinedicarboxylate)₃] Salts (M=Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, NH₄⁺, and Pyridinium⁺)

Abstract

Salts of the [Eu(2,6-pyridinedicarboxylate)₃]^3- complex anion and various monovalent inorganic and organic counterions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, NH₄ ⁺, and pyridinium⁺) have been synthesized and studied by emission spectroscopy. The Eu³⁺ ion emission spectra exhibited by these salts have been observed with high resolution (less than 1.0 cm⁻¹) and at low temperature (77 K). The emission spectra of these compounds indicate that changing the attached counterion does not affect the site symmetry observed by the europium ion beyond slight distortions indicated by small shifts in the energies of the Eu³⁺ electronic levels.

Key Words:

• Eu³⁺ luminescence
• 2,6-pyridinedicarboxylate
• counterion effect