Raman Spectral Characteristics of [Co(ida)n(dien)2−n]-Type and Related Complexes

Abstract

Abstract The Raman spectra of [Co(ida)n(dien)2−n](3−2n)+(n=0, 1, and 2), where ida and dien denote iminodiacetate and diethylenetriamine respectively, and related complexes in the skeletal vibration region were measured in order to deduce the relation between their spectra and their geometrical structures. The Raman bands could be classified into five vibration modes: Totally symmetric stretching vibration modes (polarized bands in the 510–625 cm−1 region); Co–O and Co–N stretching vibration modes (depolarized bands in the 430–525 cm−1 region); metal-ligand skeletal breathing vibration modes (polarized bands in the 360–480 cm−1 region); skeletal bending deformation modes (depolarized bands in the 290–405 cm−1 region), and chelate ring deformation modes (polarized bands in the 220–260 cm−1 region). The polarized bands around 400 cm−1 were regarded as characteristic of the mono and bis(terdentate)cobalt(III) complexes. The mer isomers of each complex gave Raman spectra clearly different from those of the fac isomers in the stretching vibration region.