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Disulfide bond dihedral angles from Raman spectroscopy
H E Van Wart1, A Lewis, H A Scheraga
1Department of Chemistry, Cornell University, Ithaca, New York 14850.
Summary
Researchers studied sulfur-sulfur (S-S) and carbon-sulfur (C-S) bonds using Raman spectroscopy. They found a linear relationship between S-S bond vibration and molecular structure, aiding in determining plant hormone configurations.
Area of Science:
- Chemical Physics
- Molecular Spectroscopy
- Crystallography
Background:
- The CS-SC moiety is present in various chemical compounds.
- Understanding the vibrational behavior of S-S and C-S bonds is crucial for molecular structure determination.
Purpose of the Study:
- To investigate the S-S and C-S stretching behavior in compounds containing the CS-SC moiety.
- To explore the correlation between S-S stretching frequency and the CS-SC dihedral angle.
- To determine the dihedral angle of malformin A using Raman spectroscopy.
Main Methods:
- Acquisition of Raman spectra for various CS-SC compounds in the solid phase (450-800 cm(-1)).
- Analysis of S-S and C-S stretching frequencies and band intensity ratios.
- Comparison of Raman data with dihedral angles obtained from X-ray diffraction, neutron diffraction, and ultraviolet absorption.
Main Results:
- A linear correlation was observed between the S-S stretching frequency and the CS-SC dihedral angle for compounds with similar CC-SS dihedral angles.
- The ratio of S-S to C-S stretching band intensities did not show a clear correlation with dihedral or bond angles, likely due to crystalline environment sensitivity.
- The determined dihedral angle for malformin A using Raman spectroscopy agreed well with ultraviolet absorption estimates.
Conclusions:
- Raman spectroscopy effectively probes the S-S and C-S stretching behavior.
- The linear dependence of S-S frequency on dihedral angle provides a valuable tool for structural analysis.
- This method offers accurate structural insights, as demonstrated by the malformin A analysis.