The ^1^3C NMR spectra of Eu(Ⅲ) complexes with alanine and histidine were investigated respectively. An interesting regularity of ^1^3C NMR shifts was revealed. The relationship between the structure of the obtained complexes and pH condition was discussed indetail. It was pointed out that the variations in ^1^3C NMR shifts were resulted from the change of the complex structure. The possibility of coordination through the nitrogen in α-amino group under a weak acidic condition was also discussed. In addition, a calculation gave a further support to this view point.

Key words: C13 NMR SPECTROMETRY, EUROPIUM ION, AMINO ACID, COMPLEX COMPOUNDS, MEDIA, ACIDITY, CHEMICAL SHIFT, SPECTROMETRIC ANALYSIS, STRUCTURAL FORM, COORDINATION