Infrared and laser Raman spectral studies of bis(dl-aspartic acid) sulfate

The infrared and Raman spectra of bis(dl-aspartic acid) sulfate in the crystalline state are recorded at room temperature and the vibrational assignments of the observed wavenumbers are made. The presence of two carbonyl (CO) groups has been identified in the title complex and the two carbonyl groups are in different environment. The extensive intermolecular hydrogen bonding in the crystal has been identified by the shifting of bands due to the stretching and bending modes of the various functional groups. The sulfate group forms the anion. Its fundamentals continue to be degenerate except for the asymmetric bending mode and it suggests that the Td symmetry of SO42− group has not been affected in the crystal.