Hydrogen bond dynamics in bulk alcohols

Keisuke Shinokita*, Ana V. Cunha, Thomas L. C. Jansen, Maxim S. Pshenichnikov

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Hydrogen-bonded liquids play a significant role in numerous chemical and biological phenomena. In the past decade, impressive developments in multidimensional vibrational spectroscopy and combined molecular dynamics-quantum mechanical simulation have established many intriguing features of hydrogen bond dynamics in one of the fundamental solvents in nature, water. The next class of a hydrogen-bonded liquid-alcohols-has attracted much less attention. This is surprising given such important differences between water and alcohols as the imbalance between the number of hydrogen bonds, each molecule can accept (two) and donate (one) and the very presence of the hydrophobic group in alcohols. Here, we use polarization-resolved pump-probe and 2D infrared spectroscopy supported by extensive theoretical modeling to investigate hydrogen bond dynamics in methanol, ethanol, and isopropanol employing the OH stretching mode as a reporter. The sub-ps dynamics in alcohols are similar to those in water as they are determined by similar librational and hydrogen-bond stretch motions. However, lower density of hydrogen bond acceptors and donors in alcohols leads to the appearance of slow diffusion-controlled hydrogen bond exchange dynamics, which are essentially absent in water. We anticipate that the findings herein would have a potential impact on fundamental chemistry and biology as many processes in nature involve the interplay of hydrophobic and hydrophilic groups. (C) 2015 AIP Publishing LLC.

Original languageEnglish
Article number212450
Number of pages11
JournalJournal of Chemical Physics
Volume142
Issue number21
DOIs
Publication statusPublished - 7-Jun-2015

Keywords

  • ECHO CORRELATION SPECTROSCOPY
  • ULTRAFAST INFRARED-SPECTROSCOPY
  • CLASSICAL MOLECULAR-DYNAMICS
  • METHANOL-WATER MIXTURES
  • LIQUID WATER
  • VIBRATIONAL SPECTROSCOPY
  • ENERGY RELAXATION
  • HYDROXYL STRETCH
  • IR SPECTROSCOPY
  • PUMP-PROBE

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