Infrared and Raman spectra of DL-histidinium dinitrate and L-histidinium sulphamate

A comparative study of the infrared and Raman spectra of DL-histidinium din itrate and L-histidinium sulphamate helps in determining the effect of hydr ogen bonding in these crystals. The nitrate compound has a carboxylic group whereas the sulphamate compound has an ionized carboxyl group. However, th e protonated imidazolium ring makes the histidine group in both cases ionic , Several group wavenumbers have been shifted in both molecules, indicating extensive hydrogen bonding. Some of the forbidden modes of the nitrate gro up have been observed, The removal of degeneracy of certain modes of both t he nitrate and sulphamate anions suggests that the symmetry of both of thes e groups have been affected in their respective environments. Copyright (C) 1999 John Wiley & Sons, Ltd.