Amide I vibrational dynamics of N-methylacetamide in polar solvents: The role of electrostatic interactions

M. F. DeCamp, L. DeFlores, J. M. McCracken, A. Tokmakoff, K. Kwac, M. Cho

Research output: Contribution to journalArticle

197 Citations (Scopus)

Abstract

The vibrational frequency of the amide I transition of peptides is known to be sensitive to the strength of its hydrogen bonding interactions. In an effort to account for interactions with hydrogen bonding solvents in terms of electrostatics, we study the vibrational dynamics of the amide I coordinate of N-methylacetamide in prototypical polar solvents: D 2O, CDCl 3, and DMSO-d 6. These three solvents have varying hydrogen bonding strengths, and provide three distinct solvent environments for the amide group. The frequency-frequency correlation function, the orientational correlation function, and the vibrational relaxation rate of the amide I vibration in each solvent are retrieved by using three-pulse vibrational photon echoes, two-dimensional infrared spectroscopy, and pump-probe spectroscopy. Direct comparisons are made to molecular dynamics simulations. We find good quantitative agreement between the experimentally retrieved and simulated correlation functions over all time scales when the solute-solvent interactions are determined from the electrostatic potential between the solvent and the atomic sites of the amide group.

Original languageEnglish
Pages (from-to)11016-11026
Number of pages11
JournalJournal of Physical Chemistry B
Volume109
Issue number21
DOIs
Publication statusPublished - 2005 Jun 2

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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