Solvent Interactions in Methanol/N,N-Dimethylamide Binary Systems Studied by Fourier Transform Infrared—Attenuated Total Reflection (FT-IR/ATR) and Two-Dimensional Correlation Spectroscopy (2D-COS)

The interaction of N,N-dimethyl formamide (DMF) and N,N-dimethyl acetamide (DMA) with methanol in solution mixtures was studied using Fourier transform infrared–attenuated total reflection (FT-IR/ATR) spectroscopy. The concentration-dependent FT-IR/ATR spectra of DMF/methanol and DMA/methanol mixtures were recorded in the wavenumber range 4000–650 cm⁻¹ to investigate wavenumber shifts as a consequence of hydrogen bonding interactions. In combination with two-dimensional correlation spectroscopy (2D-COS), the positional fluctuations observed in the v(C=O) and v(O–H) regions of DMF/DMA and methanol, respectively, have been discussed in terms of changing populations of differently hydrogen-bonded and interacting species of the same and different component molecules.