LANTHANIDE COMPLEXATION WITH AMINO-ACIDS - EU(III) WITH ALANINE IN AQUEOUS-METHANOL

In water and aqueous methanol up to 90% methanol-10% water and an ioni c strength of 1.0 M (perchlorate), europium(III) forms a 1:1 complex w ith alanine. As methanol is added to the solvent, the complexation con stants increase by less than 50% by changing the solvent from water to 90% methanol. This is different from the Eu(III)-glycine complex wher e more than an order of magnitude increase in the complexation constan t was observed. The results are consistent with inner sphere Eu(III)-g lycine and outer sphere Eu(III)-alanine complexes. (C) 1998 Elsevier S cience S.A.