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

Abstract

The betaine-sulfamic acid (2 : 1) crystal complex has been investigated by infrared and Raman experiments in polarized light and by cross-polarization magic angle spinning 13 C NMR. Very short and symmetric hydrogen bonds formed by acidic protons and betaine carboxylate groups ( -COO -H -OOC -) + are characterized by the Raman tensor a (R) available from Raman symmetric stretching vibrations of the carboxylic groups and by the 13 C shielding tensor s of these groups. The principal components of the both tensors were found as to be strongly related: s ii = 93.12 + 0.125a (R) ii . The sulfamate NH 2 group reorientation was characterized by Raman bandshape analysis at different temperatures. The energy of very weak O· · ·H -N -H· · ·O hydrogen bonds between the sulfamate and betaine moieties was characterized in this way.

Synthesis, Characterization, and Antimicrobial Investigation of a Novel Chlorhexidine Cyclamate Complex

“…As an example, chlorhexidine bands corresponding to ν­(CC), ν­(CN), and δ­(NH 2 ) vibrations are clearly evident in the region above 1480 cm –1 where sodium cyclamate has no infrared absorption. − Similarly, N–H stretching vibrations of -NH, NH, and NH 2 functional groups of chlorhexidine can be identified in the 3000–3500 cm –1 high frequency range. The cyclamate component is manifested, for instance, by the two prominent sets of bands near the 1030 and 1170 cm –1 region, associated with as/sym (SO 2 ) vibrations. , Evidence of both precursors in the prepared samples along with the fact that the vibrational bands are significantly different in their shape and positions from the initial raw materials suggests the formation of the salt between chlorhexidine and cyclamate ions. Finally, comparison of the spectrum of CHX-cyclamate synthesized in methanol versus water reveals that the two samples display overall similar vibrational profiles with some variations in their relative bands’ intensities likely originating from the small differences in the purity and local structure of the two samples.…”

Silica Bonded N-(Propylcarbamoyl)sulfamic acid (SBPCSA) Mediated Expeditious Approach to C–C Bond Formation: An Innovative Pathway for Acrylonitrile Derivatives

“…Further, the peak at about 797 and 1112 cm −1 is attributed to the typical symmetric stretching vibration of Si-O-Si and S=O bond of supported SO 3 H group, respectively. Moreover stretching vibration of S-N bond in the -HN-SO 3 H is observed at 767 cm −1 [58].…”

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.…”

“…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.…”