Premium
Quantifying Hydrogen‐Bond Populations in Dimethyl Sulfoxide/Water Mixtures
Author(s) -
Oh KwangIm,
Rajesh Kavya,
Stanton John F.,
Baiz Carlos R.
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201704162
Subject(s) - dimethyl sulfoxide , hydrogen bond , chemistry , eutectic system , sulfoxide , hydrogen , infrared spectroscopy , photochemistry , molecule , crystallography , organic chemistry , microstructure
Dimethyl sulfoxide (DMSO) disrupts the hydrogen‐bond networks in water. The widespread use of DMSO as a cosolvent, along with its unusual attributes, have inspired numerous studies. Herein, infrared absorption spectroscopy of the S=O stretching mode combined with molecular dynamics and quantum chemistry models were used to directly quantify DMSO/water hydrogen‐bond populations in binary mixtures. Singly H‐bonded species are dominant at 10 mol %, due to strong DMSO–water interactions. We found an unexpected increase in non‐hydrogen‐bonded DMSO near the eutectic point (ca. 35 mol %) which also correlates with several abnormalities in the bulk solution properties. We find evidence for three distinct regimes: 1) strong DMSO–water interactions (<30 mol %), 2) ideal‐solution‐like (30–90 mol %), and 3) self‐interaction, or aggregation, regime (>90 mol %). We propose a “step in” mechanism, which involves hydrogen bonding between water and the DMSO aggregate species.