TY - JOUR AU - Jovanovski, Gligor AU - Makreski, Petre AU - Šoptrajanov, Bojan PY - 2008/06/15 Y2 - 2024/03/28 TI - Vibrational study and spectra-structure correlations in magnesium disaccharinate heptahydrate, Mg(sac)2⋅7H2O JF - Macedonian Journal of Chemistry and Chemical Engineering JA - Maced. J. Chem. Chem. Eng. VL - 27 IS - 1 SE - Spectroscopy DO - 10.20450/mjcce.2008.239 UR - https://mjcce.org.mk/index.php/MJCCE/article/view/239 SP - 1-8 AB - <p>Infrared and Raman vibrational spectra of magnesium disaccharinate heptahydrate, Mg(sac)<sub>2</sub>⋅7H<sub>2</sub>O, in the 4000–380 cm<sup>–1</sup> region (for infrared) and 4000–100 cm<sup>–1</sup> region (for Raman) were studied. The assignment of the spectra was based on the experimental data for the previously studied metal saccharinates as well as the literature data for the <em>ab initio </em>calculations on the free deprotonated saccharinato species. Special attention was paid to the analysis of the H<sub>2</sub>O, CO and SO<sub>2</sub> stretching modes. The spectral picture in the regions of the water, carbonyl and sulfonyl stretches is correlated with the number of the crystallographically determined non-equivalent H<sub>2</sub>O, CO and SO<sub>2</sub> structural units. It was found that the presence of seven crystallographically different water molecules in the structure (fourteen different Ow⋅⋅⋅O and Ow⋅⋅⋅N distances) is not reflected in the appearance of the expected fourteen IR bands in the region of the OD stretching vibrations of the isotopically isolated HDO molecules. This must be due to the existence in the structure of several Ow⋅⋅⋅O or Ow⋅⋅⋅N hydrogen bonds with very similar strengths causing an overlap of the corresponding bands in the spectrum. Despite the presence of two carbonyl groups with practically identical C–O distances [124.2(3) and 124.0(3) pm], two clearly separated bands are registered in the carbonyl stretching region of the IR (1660 and 1627 cm<sup>–1</sup>) and Raman spectrum (1648 and 1620 cm<sup>–1</sup>). On the other hand, although two nonequivalent SO2 groups are present in the structure of Mg(sac)<sub>2</sub>⋅7H<sub>2</sub>O, only one pair of bands due to SO<sub>2</sub> stretchings [νas(SO<sub>2 </sub>and νs(SO<sub>2</sub>) modes] is registered in the IR spectrum.</p> ER -