Vibrational spectral analysis of l-lysine l-lysinium dichloride nitrate

The infrared and Raman spectra of l-lysine l-lysinium dichloride nitrate were recorded at room temperature and the vibrational assignments of the observed bands were made. The presence of both the carbonyl and ionized carboxylic groups has been identified in the title complex. The lysine and lysinium residues form a dimer through a strong OH⋯OOH⋯O bond between them in the crystal. This together with the different environments has seen by the four –CH2– groups in each skeleton cause several of the functional group wavenumbers to occur as doublets or as broad bands. Some of the forbidden modes of the nitrate group have been observed. The extensive intermolecular hydrogen bonding in the crystal was identified by the shifting of bands due to the stretching and bending modes of the various functional groups.