Dipole moments of the carbonyl groups in cyclic ?-diketones from IR spectroscopy data

1995 ◽  
Vol 44 (4) ◽  
pp. 670-677
Author(s):  
L. M. Pisarenko ◽  
A. V. Nikitin
Keyword(s):  
Ir Spectroscopy ◽  
Dipole Moments ◽  
Spectroscopy Data ◽  
Carbonyl Groups

Calculation of the development of the Portlandite content based on FT-IR spectroscopy data

2020 ◽  
Author(s):  
Milena Pavlíková ◽  
Lenka Scheinherrová ◽  
Martina Záleská ◽  
Zbyšek Pavlík
Keyword(s):  
Ir Spectroscopy ◽  
Spectroscopy Data ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Protein secondary structure from FT-IR spectroscopy: correlation with dihedral angles from three-dimensional Ramachandran plots

1991 ◽  
Vol 69 (11) ◽  
pp. 1639-1642 ◽  
Author(s):  
Michael Jackson ◽  
Henry H. Mantsch
Keyword(s):  
Ir Spectroscopy ◽  
Three Dimensional ◽  
Protein Secondary Structure ◽  
Secondary Structures ◽  
Dihedral Angles ◽  
Carbonyl Groups ◽  
Amide Carbonyl ◽  
Ft Ir ◽  
Ft Ir Spectroscopy ◽  
Hydrogen Bonded

The frequency of the so-called "amide I" band (amide C=O stretching vibration, vC=O) of proteins is discussed in terms of the dihedral angles of the various secondary structures present within proteins. We propose that in the case of intra- or intermolecular hydrogen-bonded amide carbonyl groups the frequency of this absorption can be directly related to the [Formula: see text], ψ angles of the amide moieties for the major secondary structures. Amide I bands at frequencies above those found for non-hydrogen bonded amide carbonyl groups are rationalized in terms of a change in the third dihedral angle, ω. Rotation around the amide C—N bond in sterically demanding structures, such as turns where ω deviates from 180°, is expected to cause an increase in the electron density of the amide carbonyl groups and so increase vC=O to frequencies greater than that seen for unperturbed carbonyl groups. Key words: FT-IR spectroscopy, proteins, structure, dihedral angles.

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