No abstract

No abstract

The present research has studied the spectral data, thermochemical transformations and hydrolysis of hexafluorosilicates with guanidine containing cations (C 22 H 32 Cl 2 N 10)SіF 6 (І) and (C 21 H 45 N 9)(SiF 6) 1.5 (ІІ) for their potential use as caries-preventive and antibacterial agents. Hexafluorosilicates of the composition I and II were separated as crystalline products of interaction of hexafluorosilicic acid with the methanol solutions of chlorhexidine hydrochloride and polyhexamethylene guanidine hydrochloride. The compounds isolated have been characterized by IR, NMR 19 F, mass-spectrometry, thermogravimetric analysis, potentiometry. According to IR spectroscopy data, "onium" hexafluorosilicates I and II have ionic structures. The vibrations of the groups ν(NH), ν(N + H 2) in salts I and II appear as strong absorption bands at 3360-3180 cm-1 ; δ(N + H 2) vibrations appear at 1634 and 1637 cm-1. The strong ν(SiF) and δ(SiF 2) stretches of SiF 6 2anions are observed in their characteristic regions (at 744, 734 and 482 cm-1 , respectively). The singlet character of ν(SiF) and δ(SiF 2) vibrations indicates the absence of noticeable distortion of symmetry of SiF 6 2anion with regard to O h. The NMR 19 F spectra of compounds I and II (in DMSO-d 6 solutions) have one resonance at-136,70,-135,09 ppm (SiF 6 2-); additional resonance at-123,14 ppm, in the case of II it can be related to the octahedral complex anion [SіF 5 (ДМСО)]-. The results of thermogravimetric analysis are consistent with a multi-stage thermolysis scheme for hexafluorosilicates I and II. The temperatures of thermolysis beginning of complexes I and II are 270 and 100°C, respectively. The compounds I and II studied are characterized by the predicted tendency to hydrolysis in dilute aqueous solutions with formation of orthosilicic acid and fluoride ions, and it allows considering these salts as potential anticaries agents. The study of the biological activity of these compounds is the subject of further investigations.

No abstract

No abstract