Hexafluorosilicates of bis(aminopyridinium). The relationship between H-bonding system and solubility of salts

Interaction of hexafluorosilicic acid with sulfa drugs. Bis(sulfathiazolium) hexafluorosilicate: Spectral data and crystal structure

“…This work continues the previous research on the correlations between the structure and properties of ''onium'' hexafluorosilicates [2,3] and is devoted to the interaction products formed by the sulfa drugs sulfathiazole (stz) and sulfalen (sl) with hexafluorosilicic acid. This choice is explained by our interest to the co-crystals of sulfa drugs, products of their transformations or other active pharmaceutical ingredients (APIs) [4] possessing H-donor/H-acceptor functions with co-crystal partners of different nature [5,6].…”

“…Thus, the interaction of hexafluorosilicic acid with sulfathiazole results in the formation of bis(sulfathiazolium) hexafluorosilicate, whereas the reaction involving sulfalen leads to its hydrolysis with the cleavage of the C-N bond and formation of bis[(4-aminosulfonyl)benzeneammonia] hexafluorosilicate. The solubility of the studied salts, as for the previously studied hexafluorosilicates with functionalized pyridinium cations [2,3], correlates with the number of short interionic H-bonds in their structures.…”

“…The deformation vibrations of the cation are also visible in the range of the stretching vibrations of the phenyl and thiazole rings n ring (1650-1505 cm À1 ) and in the range of 750-680 cm À1 of the n(SiF) vibrations of the anion (Table 1) Being one of the most important physical and chemical properties of the pharmaceuticals, the water solubility is crucial for solving the problems of chemical technology, ecology, and pharmacology [15]. As we have recently shown [3] the water solubility (C) of a number of pyridinium hexafluorosilicates correlates with the parameter h = n/d(DÁ Á ÁA) av. , where n is a number of short interionic contacts (H-bonds) and d(DÁ Á ÁA) av.…”

“…As it has been previously noted [1], the system of interionic XHÁ Á ÁF (X = N, O) H-bonds in the solid ''onium'' fluorosilicates has a significant impact on the structural characteristics and properties of the final salts. In particular, the observed inverse-proportional relationship [2,3] between the pyridinium hexafluorosilicates' water solubility and a number of short interionic H-bonds in the crystalline salts has an exponential character. The functionalization of the ''onium'' cation by the H-donor substituents, differing in the number and nature of the H-donor centers, might serve as a convenient method to detect the directional changes in physicochemical characteristics of the ''onium'' hexafluorosilicates.…”

Synthesis and Structural Study of Some Pyrimidinium Hexafluoridosilicates

“…[1][2][3][4][5][6][7][8][9][10][11] Otherwise the ionic compounds with pyrimidinium cation and some counter anion are relatively rare. 12 To the best of our knowledge, only one structural report in the CSD includes pyrimidinium fragment and hexafluoridosilicate anion.…”