Premium
FT‐IR and FT‐Raman spectral studies of bis( L ‐proline) hydrogen nitrate and bis( L ‐proline) hydrogen perchlorate
Author(s) -
Pandiarajan S.,
Umadevi M.,
Sasirekha V.,
Rajaram R. K.,
Ramakrishnan V.
Publication year - 2005
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1390
Subject(s) - raman spectroscopy , proline , chemistry , perchlorate , nitrate , inorganic chemistry , hydrogen , hydrogen bond , nuclear chemistry , organic chemistry , molecule , biochemistry , ion , amino acid , physics , optics
FT‐IR and FT‐Raman spectra were recorded for bis( L ‐proline) hydrogen nitrate and bis( L ‐proline) hydrogen perchlorate crystals. The wavenumber assignments have been made for the proline functional groups, viz. COOH, COO − , CNCCC ring, [NH 2 ] + , (CH 2 ), CCN and CH. In both crystals, two proline residues share one proton and become monoprotonated. The observed bands show that in both compounds one of the proline residues is in the zwitterionic form while the other is in the cationic form. In the two compounds under investigation, the vibrational bands for the proline residues are almost similar. In the pyrrolidine ring there exists a protonated imino group [NH 2 ] + and CH 2 groups showing the aliphatic nature of the proline in the inorganic acid environments. The symmetry of the nitrate group is not affected. Hydrogen‐bonding network leads to the shifting of bands corresponding to several stretching and deformation modes. In bis( L ‐proline) hydrogen perchlorate, the identification of bands due to ClO 2 group reveals that the symmetry of ClO 4 − anion is possibly reduced to C 2 v . Copyright © 2005 John Wiley & Sons, Ltd.