Normal coordinate analysis and DFT calculations of the vibrational spectra for lanthanide(III) complexes with 3-bromo-4-methoxy-2,6-lutidine N-oxide: LnCl3(3Br4CH3OC7H7NO)3 (Ln=Pr, Nd, Sm, Eu, Gd, Dy)

The results of the FT-Raman and FT-IR studies of the LnCl3(LNO)3 type complexes (where Ln=Pr, Nd, Sm, Eu, Gd, Dy and LNO=3-Br-4-CH3OC7H7NO) are presented. The spectral contours observed in the regions of the lanthanide-oxygen, lanthanide-chlorine and nitrogen-oxygen vibrations are employed in the discussion of the molecular structure of the complex ions and the local symmetry of the LnCl3(ON)3 polyhedron. The discussion of the vibrational spectra is based on the classical normal coordinate analysis and its results are compared to the results of DFT quantum chemical calculations performed for complete molecule. The normal coordinate analysis has been performed for PrCl3(ON)3 and DyCl3(ON)3 molecular systems, which have been treated as a different ‘isotopic units’. Basing on the predominant PED contributions of the respective internal coordinates the assignment of the normal vibrations has been proposed.