Vibrational (FT-IR and FT-Raman) and NMR studies on selected metal (Ca, Mn, Zn) complexes with ortho-, meta-, and para-iodobenzoic acids

The vibrational (FT-IR and FT-Raman) and NMR (¹H and ¹³C) spectra of Ca, Mn, and Zn complexes with ortho-, meta-, and para-iodobenzoic acids have been studied. The solid state samples of all complexes have been measured within the range 4000–400 cm^?1, while water solutions of ortho-iodobenzoates within the range 4000–800 cm^?1. Based on previous experimental data and normal mode calculations for simpler complexes the assignment of bands observed in vibrational spectra of studied compounds has been done. Some significant differences in vibrational structure (frequency and intensity of selected bands) have been observed and discussed. The effect of metal on ring vibrations and carboxylic anion stretching and deformation has been investigated. Also, influence of iodine substitution on the aromatic ring and carboxylic anion, depending on iodine ring position, has been discussed. In case of soluble compounds, wavenumbers of characteristic bands of water solution samples have been compared with wavenumbers of corresponding bands of solid state samples.