Hydrogen Bonding Interactions in Three 2-Mercaptoethanol Systems: An Excess Infrared Spectroscopic Study

Abstract

The hydrogen bonding properties of a representative molecule, 2-mercaptoethanol (ME), of which two functional groups OH and SH are believed to interact competitively or selectively with proton-accepting molecules, have been studied. Three binary systems, namely ME-CCl(4), ME-dimethyl sulfoxide (DMSO), and ME-acetone, were investigated with excess infrared absorption spectroscopy. It is found that when DMSO or acetone is added into ME, they preferentially form hydrogen bonds with OH, and the hydrogen bonds in the ME-DMSO system are stronger than those in the ME-acetone system. When CCl(4) is added into ME, the weak hydrogen bonds involving the SH group are broken preferentially with increasing CCl(4) concentration. The dissociation process of ME in the inert diluent CCl(4) over the entire concentration range has been discussed in detail. In the very low concentration range of CCl(4), the highly hydrogen bonded ME multimers mainly break into medium-sized aggregates. The amount of the trimers and dimers first increases and then, at x(CCl(4)) = 0.77, begins to decrease. These results suggest that excess infrared spectroscopy can provide detailed molecular pictures in liquid solutions containing complex hydrogen bonding interactions. It can also help to locate individual peak positions in the deconvolution of overlapped absorption bands.

The Structures of ZnCl2-Ethanol Mixtures, a Spectroscopic and Quantum Chemical Calculation Study

“…The amphiphilicity of alcohols results in a high complexity of their structures rendered by various intermolecular interactions, most importantly hydrogen bonds (H-bonds) [ 6 , 7 , 8 ]. The H-bonded networks in alcohols are readily susceptible to disruption and reformation by chemical perturbations [ 9 , 10 , 11 ]. Structural properties of alcohols in pure state or mixed with cosolvents and their relationship with H-bonds have been the subject of numerous experimental and computational studies [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”

Influence of Hydration on the Structure and Interactions of Ethaline Deep‐Eutectic Solvent: A Spectroscopic and Computational Study

“…The changes in peak positions and intensities can only provide limited information about the interactions in the mixtures. Excess spectroscopy has the capability of elucidating veiled changes undetectable in original spectra In general, positive and negative peaks of the excess spectra are indicative of the fine structures of the mixtures. Figure B depicts the excess IR absorption spectra of ETH‐D 2 O system in v (O−H) and v (C−H) regions.…”

“…Excess IR spectroscopy theory has been described in detail in literatures . Briefly, an excess IR spectrum is expressed as the difference between the spectrum, in terms of molar absorptivity, of a real solution and that of the respective ideal solution under identical conditions.…”

Formation of Molecular Complexes in Liquid Benzene-Chloroform Mixtures Examined by Mid-IR 2D Correlation Spectroscopy and Multivariate Curve Resolution

“…The analysis of residual spectra is a simple, but, at the same time, useful tool for the investigation of the intermolecular interaction in binary solutions [19,20,23,24]. The main idea is the consideration of deviations from Beer's law.…”