Synthesis, Characterization and Fluorescence Properties of Cryptates of Sm(III), Eu(III), Tb(III), Dy(III) with a N2O6 Cryptand

Abstract

Four solid cryptates of a cage-type N2O6-heteroatom cryptand (L) with Ln(III) nitrates (Ln=Sm, Eu, Tb, Dy) have been prepared and characterized by elemental analyses, IR spectra, thermogravimetric analyses, fluorescence spectra and molar conductance measurements. The obtained data indicate the formation of 2:1 (Ln:L) ratio with the general formula Ln2(NO3)6 · L · nH2O (n=2 or 5) and the structure [Ln(L)(NO3)(H2O)][Ln(NO3)5] · (n−1)H2O (n=2 or 5) has been suggested. The TG analyses indicate the presence of hydrated and coordinated water molecules. The fluorescence properties of these complexes show that all cryptates have strong fluorescence intensity. That the Eu(III) complex has the strongest fluorescence intensity shows that the triplet state energy of the cryptand matches with the Eu(III) vibration energy level.