New complexes of rare earth elements with 3-methyladipic acid

Rare earth element 3-methyladipates were prepared as crystalline solids wit h general formula Ln(2)(C7H10O4)(3). nH(2)O, where n=6 for La, n=4 for Ce, Sm-Lu, n=5 for Pr, Nd and n=5.5 for Y. Their solubilities in water at 293 K were determined (2.10(-3)-1.5.10(-4) mol dm(-3)). The IR spectra of the pr epared complexes suggest that the carboxylate groups are bidentate chelatin g. During heating the hydrated 3-methyladipates lose all crystallization wa ter molecules in one (Ce-Lu) or two steps (Y) (except of La(III) complex wh ich undergoes to monohydrate) and then decompose directly to oxides (Y, Ce) or with intermediate formation of oxocarbonates Ln(2)O(2)CO(3) (Pr-Tb) or Ln(2)O(CO3)(2) (Gd-Lu). Only La(III) complex decomposes in four steps formi ng additionally unstable La-2(C7H10O4)(CO3)(2).