稀土硝酸盐15-冠-5络合物的一些性质

PROPERTIES OF THE COMPLEXES OF RARE EARTH NITRATES WITH 15-CROWN-5

稀土冠醚络合物的组成和稳定性不但与稀土离子直径和冠醚孔径是否匹配,而且也和阴离子及合成用的溶剂有关.因15-冠-5(简写15C5)的孔径(2.2?)和大部分稀土离子直径相近.因此它们的络合物是研究孔径匹配关系的理想模型. Bunzli在乙腈中合成了大部分镧系硝酸盐15C5络合物,轻镧系(La-Gd)生成1:1无水络合物,重镧系(Tb-Lu)为含1—3分子水的1:1络合物.

Using dry acetone as solvent, the solid complexes of lanthanides, yttrium and scan-dium nitrate with 15-crown-5 have been prepared. According to elemental analysis, thecompositions of the complexes were found to be RE(NO_3)_3·15C5 for La-Eu and RE(NO_3)_3·15C5·3H_2O for Gd-Lu, Y and Sc. Some of their. properties were determined bythermoanalysis, IR and XPS.