Related Experiment Video
Updated: Jun 6, 2026

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
Transient infrared spectra of CH3SOO and CH3SO observed with a step-scan Fourier-transform spectrometer
1Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan.
Abstract:
A step-scan Fourier-transform spectrometer coupled with a multipass absorption cell was employed to monitor time-resolved infrared absorption of transient species produced upon irradiation at 248 nm of a flowing mixture of CH(3)SSCH(3) and O(2) at 260 K. Two transient bands observed with origins at 1397±1 and 1110±3 cm(-1) are tentatively assigned to the antisymmetric CH(3)-deformation and O-O stretching modes of syn-CH(3)SOO, respectively; the observed band contour indicates that the less stable anti-CH(3)SOO conformer likely contributes to these absorption bands. A band with an origin at 1071±1 cm(-1), observed at a slightly later period, is assigned to the S=O stretching mode of CH(3)SO, likely produced via secondary reactions of CH(3)SOO. These bands fit satisfactorily with vibrational wavenumbers and rotational contours simulated based on rotational parameters of syn-CH(3)SOO, anti-CH(3)SOO, and CH(3)SO predicted with density-functional theories B3LYP/aug-cc-pVTZ and B3P86/aug-cc-pVTZ. Two additional bands near 1170 and 1120 cm(-1) observed at a later period are tentatively assigned to CH(3)S(O)OSCH(3) and CH(3)S(O)S(O)CH(3), respectively; both species are likely produced from self-reaction of CH(3)SOO. The production of SO(2) via secondary reactions was also observed and possible reaction mechanism is discussed.
Related Concept Videos
IR Spectroscopy: Molecular Vibration Overview
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
UV–Vis Spectroscopy: Molecular Electronic Transitions
IR and UV–Vis Spectroscopy of Carboxylic Acids
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency, 1710 cm−1. The C=O bond of the...
Spectroscopy of Carboxylic Acid Derivatives
In the...
Raman Spectroscopy: Overview
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and the...
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
According to Hooke's law, the vibrational frequency is directly proportional to the...

