|Ultima descărcare din IBN:|
| SM ISO690:2012|
SHYSHKIN, Ivan; FONARI, Marina; KRAVTSOV, Victor; GELMBOLDT, Vladimir. Synthesis, structure and some properties of 4-hydroxymethylpyridynium hexafluorosilicate. In: Achievements and perspectives of modern chemistry. 9-11 octombrie 2019, Chişinău. Chisinau, Republic of Moldova: Tipografia Academiei de Ştiinţe a Moldovei, 2019, p. 240. ISBN 978-9975-62-428-2.
|Achievements and perspectives of modern chemistry 2019|
Conferința "International Conference "Achievements and perspectives of modern chemistry"" |
Chişinău, Moldova, 9-11 octombrie 2019
Caries is one of the most common diseases, and in childhood, this pathology ranks first among chronic diseases. In recent years, ammonium hexafluorosilicates have been the objects of extensive studies as novel promising anti-caries and hyposensitive agents. In order to enhance the use of ammonium hexafluorosilicate as anti-caries agents, we conducted a synthesis, studied the structure and some properties of 4-hydroxymethylpyridinium hexafluorosilicate (I). Synthesis of hexafluorosilicate was carried out by interacting the methanol solution of 4-hydroxymethylpyridine with 45 % H2SiF6 in the molar ratio of components1 : 3. The resulting reaction product is characterized by elemental analysis, mass spectrometry, IR spectroscopy and X-ray diffraction. According to the X-ray diffraction, the geometry of the SiF6 2+ anion in I is a distorted octahedron: the Si–F bond lengths are in a range 1.6780(11)–1.6877(11) A. The difference in the Si–F bond lengths is explained by the involvement of fluorine atoms of the anions in H-bonds NH***Fand NH***Oof different strength with H-donor moieties of the cations.formulaFigure. Formula unit of compound I with hydrogen bonds In the three-term formula unit (LH)2SiF6 the hexafluorosilicate anion is located in the inversion center; the organic cation occupies a general position, being practically in the anion plane. The intense absorption bands at 738cm–1 [v(SiF)] and 482 cm–1, 423 cm–1, 403 (shoulder) cm–1 [d(SiF2)] in the IR spectrum of I are assigned to the SiF6 2- anion vibrations. An essential factor for a medicinal substance, which significantly affects its bioavailability, is the solubility of the compound in water. The solubility of the complex in water and organic solvents: very easily soluble in water, easily soluble in DMSO, poorly soluble in methanol and ethanol (96 %). The calculated degree of hydrolysis a of salt I in the 1*10–4 M aqueous solution is expectedly high, being 87.3 % which indicates a high degree of SiF62- ion conversion in diluted solutions with the formation of silicon dioxide and the release of fluoride ions:SiF62– + 4H2O= Si(OH)4 + 6F– + 4H+ .The latter is important in the context of clarifying the prospects for using I as a carioprotective agent. This hexafluorosilicate has good solubility, a high degree of hydrolysis in a dilute aqueous solution, and can serve as a potential target for further biological research.