对称吡啶双酰胺及其稀土配合物的合成、表征与荧光性质的研究

Synthesis, Characterization and Luminescence Properties of Rare Earth Complexes with Bis(Pyridinyl-Amide)

以元素分析、红外光谱、差热及核磁进行表征了配体及其五种稀土(La3+,Eu3+,Tb3+,Gd3+,Yb3+)配合物,确定了其组成,研究了部分配合物的固态荧光。同时以低温磷光光谱确定了配体的三重态能级为22989cm-1,研究了配体与稀土离子的能级匹配情况,详细讨论了配合物的发光性能。结果发现,铽配合物能发出很强的特有荧光,而铕配合物所发荧光很弱,说明配体L与Tb3+的5D4匹配。对于Tb3+而言,当2000cm-1<ΔE(T-5D4)<3000cm-1时,稀土铽离子发出强的荧光;对于Eu3+而言,ΔE(T-5D1)超过3000cm-1时,则几乎不发荧光。

A ligand, N^1, N^4-di （ pyridin-2-yl ） succinamide （L） and its lanthanide（Ⅲ） complexes （RE = La, Eu, Tb, Gd, Yb ） were synthesized and characterized in detail. The results indicate that the composition of the binary complexes is determined as [ REL （H2O）2（NO3）2] NO3, that the complexes are 1：1 electrolytes in DMF, and that the Tb^3＋ complex has brightly green fluorescence in a solid state. At the same time, the energy levels of the excited triplet states for the six ligands were determined to be 22989 cm^-1. The fact that the ligand sensitize Tb^3＋ complexes was explained by the relative energy gap between the lowest triplet energy level of the ligands （T） and ^5DJ of Tb^3＋ or Eu^3＋. When 2000 cm^-1〈 △E（T-^5D4） 〈 3000 cm^-1, the luminescent intensity of the Tb^3＋ complex is stronger. When 3000 cm^-1 〈 △E（T-^5D1）, the luminescent intensity of the Eu^3＋ complex is weaker or close to nil. This means that the triplet energy level of the ligand is a chief factor that dominates RE^3＋ luminescence.