Changes in spectral features with varying mole fractions of anisaldehyde in binary mixtures

Abstract

Raman and IR spectra of neat anisaldehyde (4-methoxybenzaldehyde (4MeOBz)) and its binary mixtures (in polar and nonpolar solvents) with varying mole fraction of 4MeOBz were investigated. The concentration dependence of the wavenumber position and line width (full width at half maximum, FWHM) was analyzed to study the interaction of the solute vibrational modes with the microscopic solvent environment. The wavenumbers of Raman modes of 4MeOBz, namely, the carbonyl stretching, aldehydic d (C-H) and ringbreathing modes, showed a linear variation in the peak position for varying concentrations of 4MeOBz in the different solvents. The dependence of Raman line width with concentration of 4MeOBz of these modes was also taken into account. The solute-solvent interaction is stronger in 2-propanol and acetonitrile because of the formation of hydrogen bonds between them, whereas in benzene the interaction is too weak to affect the Raman modes. The modes, n (C O) in 2-propanol and aldehydic d (C-H) in acetonitrile, gave a Gaussian-type line width variation, which was explained by the concentration fluctuation model, and the linear variation of the line widths was also interpreted by solute-solvent interactions. IR spectra were taken for these binary mixtures, which also give further support to these data.

Recent advances in linear and nonlinear Raman spectroscopy II

“…Umadevi et al 147 performed Raman spectral investigations of the binary system acetic acid/N, N-dimethyl formamide in order to study the formation of self-associated dimer and hydrogen-bonded complexes in the mixed system, extending former work on similar solutions by Tukhvatullin et al 148 and Ojha et al 149 Anisaldehyde [4-methoxybenzaldehyde (4MeOBz)] is a very interesting carbonyl-containing system. Vibrational spectra of neat and binary mixtures (in polar and nonpolar solvents) of 4MeOBz were investigated by Fathima et al 150 The goal of these studies was to understand the spectral changes as a function of 4MeOBz mole fraction in terms of self-association and solute-solvent interactions. The same authors 151 carried out a concentrationdependent study on salicylaldehyde in binary mixtures.…”