Raman and infrared spectra of calcium and barium sulphamates

Abstract

Raman spectra of a single crystal of calcium sulphamate and polycrystalline barium sulphamate have been recorded at room temperature. Infrared spectra of polycrystalline calcium and barium sulphamates for the region 20-4000 cm-' are also presented. The assignments made are supported by potential energy distribution calculations. The data show that there is no water of hydration in barium sulphamate. The N-S torsional mode is observed in both the compounds. This has not been found in other sulphamates of this family. The results indicate very weak hydrogen bonding in these crystals.

Raman, infrared and 13C NMR studies on betaine–sulfamic acid (2:1) crystal and its hydrogen bonds

“…Three bands due to the 1 A 1 and 2 2 A 1 vibrations is suggested by their almost identical intensities. 10 Our observations do not confirm the existence of such an interaction in the crystal studied.…”

“…Their vibrational wavenumbers in the sulfamic acid are as follows: 1 and 4 E D 551 cm 1 . 10 In sulfamates the corresponding bands are observed in the following wavenumber regions: 1030-1080, 470-570, 1170-1270 and 490-600 cm 1 , respectively. 11 -13 In the complex studied and also in typical sulfamates the NH 2 SO 3 anion symmetry is reduced to C 1 and the degeneracy is removed.…”

Vibrational and thermal properties of crystalline topiramate

“…However, the N-S torsion is tentatively attributed to the band at 332 cm -1 , closer to 300 cm -1 as assigned to other sulfamates, 14,15,17 and accounting for hydrogen bonding effects. The bands at 352 and 386 cm -1 are assigned, respectively, to the SO 3 group symmetric and asymmetric rocking modes, also as in other sulfamates.…”

“…3110 cm -1 can be attributed to an overtone due to Fermi resonance from the amine group scissoring mode, as occurs for other sulphamates. 10,11,14 The asymmetric stretchings of CH 3 are observed at 3003 (in phase) and 2989 cm -1 (out of phase), followed by the asymmetric stretching of endocyclic CH 2 group at 2979 cm -1 . The band observed at 2962 cm -1 is assigned to the symmetric stretching of exocyclic CH 2 ; this value is almost 30 cm -1 higher than that observed for fructopyranose.…”

“…Modes with wavenumber lower than 150 cm -1 are generally assigned as lattice modes. 9 The tentative assignments of bands observed in the Raman and in the IR spectra of topiramate, based on published vibrational studies on other sulfamates [10][11][12][13][14][15][16][17] and studies on other correlated materials, 18-23 as well as DFT calculations, are given in Table 2. In each case, the most intense band was given a value of 100, and relative intensities are shown in parentheses.…”