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Title: Structural dynamics of N-ethylpropionamide clusters examined by nonlinear infrared spectroscopy

In this work, the structural dynamics of N-ethylpropionamide (NEPA), a model molecule of β-peptides, in four typical solvents (DMSO, CH{sub 3}CN, CHCl{sub 3}, and CCl{sub 4}), were examined using the N—H stretching vibration (or the amide-A mode) as a structural probe. Steady-state and transient infrared spectroscopic methods in combination with quantum chemical computations and molecular dynamics simulations were used. It was found that in these solvents, NEPA exists in different aggregation forms, including monomer, dimer, and oligomers. Hydrogen-bonding interaction and local-solvent environment both affect the amide-A absorption profile and its vibrational relaxation dynamics and also affect the structural dynamics of NEPA. In particular, a correlation between the red-shifted frequency for the NEPA monomer from nonpolar to polar solvent and the vibrational excitation relaxation rate of the N—H stretching mode was observed.
Authors:
; ;  [1] ;  [1] ;  [2]
  1. Beijing National Laboratory for Molecular Sciences, Molecular Reaction Dynamics Laboratory, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22493239
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION; ABSORPTION SPECTROSCOPY; ACETONITRILE; AGGLOMERATION; CARBON TETRACHLORIDE; CHLOROFORM; COMPUTERIZED SIMULATION; CORRELATIONS; DIMERS; DMSO; EXCITATION; INFRARED SPECTRA; MOLECULAR DYNAMICS METHOD; MOLECULES; MONOMERS; NONLINEAR PROBLEMS; PEPTIDES; RED SHIFT; SOLVENTS; TRANSIENTS