Crystal structure and spectroscopic analyses of guanylurea hydrochloride. Evidence of the influence of hydrogen bonding on the π-electron delocalization

Abstract

The crystal structure, and a complete vibrational analysis by FTIR and Raman spectra, of guanylurea hydrochloride are presented. The crystallographic results show a pronounced π-electron delocalization on the cation and the presence of strong intra- and inter-molecular hydrogen bonding interactions between amino groups belonging to the guanidine moiety and the carbonyl oxygen of the ureic group. This arrangement gives rise to a polymer-like structure, in which the guanylurea cation chains are laterally hydrogen bonded by Cl^– anions and water molecules. The UV–VlS reflectance spectra are in agreement with the hypothesis of the existence of hydrogen bonding charge transfer complexes in the solid state. Other spectroscopic techniques, such as FTIR and Raman, have been employed to support the crystal data, and to investigate the vibrational assignments for this compound.