Raman spectroscopic study on the coordination behavior of rare earth ions in N-methylacetamide.

The coordination behavior of rare earth (Ln (3+)) ions in N-methylacetamide (NMA) solution has been investigated at room temperature by Raman spectroscopy. The behavior of the symmetric Raman Ln-Cl stretching (nu Ln-Cl) band, and amide I (nu AI), and III (nu AIII) bands of NMA with the rare earth series is discussed in conjunction with the change in the coordination structure occurring in the middle of the rare earth series. A competition for a coordination equilibria between a Cl (-) ion and an NMA molecule from the rare earth chloride-NMA complex might occur in the middle rare earth region. It is demonstrated that the change in the coordination structure of Ln (3+) ions in NMA is due to an elimination of an NMA molecule.