[Studies on the infrared spectra of rare earth complexes with pyruvic acid]

FT-IR spectra of La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho and Y complex with pyruvic acid have been studied. The principal infrared absorption peaks are assigned for the region 400- 2 000 cm(-1). Three IR peaks in the region 200-400 cm(-1) are shifted obviously to higher frequency with increasing of the atomic number of rare earth ion, these were believed to be RE-O bond stretching mode absorptions. The IR spectra also indicated that the carboxylate groups have the form of chelation bridging tridentate to rare earth ions, i. e., one of the carboxyl oxygens was shared between two adjacent metal ions, moreover, the splitting and broad bands are existed in IR spectra of the rare earth complexes. The RE-O bond of the complexes is principally ionic.