INVESTIGATING ACETONITRILE VIBRATIONS IN PROTIC AND APROTIC MIXTURES

Polarized Raman spectroscopy and two-dimensional correlation spectroscopy (2D-COS) were used to study the vibrational behavior of acetonitrile (ACN) in mixtures with dimethyl sulfoxide (DMSO) and water. The Raman non-coincidence effect (NCE) of the C≡N stretching mode revealed weak dipole interactions in ACN-DMSO and strong hydrogen bonding in ACN-water. Synchronous and asynchronous 2D-COS spectra showed that ACN vibrations respond differently to solvent concentration changes, with significant spectral shifts in water due to hydrogen bonding. These findings demonstrate how 2D-COS effectively reveals solvent-induced vibrational interactions in molecular systems