ATR-FTIR studies of ion–solvent and ion–ion interactions in divalent-metal perchlorate–acetonitrile solutions

Abstract

The effect of divalent-metal ions on the IR spectrum of acetonitrile has been examined by studying the dependence of the spectral features on concentration for seven divalent-metal-ion perchlorates. Data are reported for both the frequency shifts and molar absorption coefficients of the major bands in acetonitrile which are affected by the presence of a cation in solution. It is shown that ion association plays a major role in determining the magnitude of the frequency shift. Other features discussed include the effect of the combination band in protonated acetonitrile, and the role of metal-ion softness in cation–acetonitrile interactions.