Phosphorus-nitrogen compounds. Part 48. Syntheses of the phosphazenium salts containing 2-pyridyl pendant arm: Structural characterizations, thermal analysis, antimicrobial and cytotoxic activity studies

Abstract

The phosphazenium salts (protic ionic liquids, PILs/protic molten salts, PMOSs) (6a-6d and 7a) of the free phosphazene bases (4a-4d and 5a) were prepared by the reactions of the corresponding cyclotriphosphazenes with the bulky gentisic acid. The structures of the PMOS were evaluated using the elemental analyses, FTIR, ¹H, ¹³C{¹H} and ³¹P{¹H} NMR data. The molecular and crystal structures of 4a and 6c were established by X-ray crystallography. The thermal properties of the PMOS were determined using TG and DTA techniques. On the other hand, the antimicrobial activities of the free phosphazene bases (4a-4d and 5a-5d) and PMOSs (6a-6d and 7a) were screened against the selected bacteria and yeast strains. The antimicrobial activities of the free phosphazene bases and the PMOSs were compared. The interactions of the phosphazenes and their salts with plasmid DNA were elucidated by the agarose gel electrophoresis. The evaluations of the cytotoxic activities of these compounds were also studied against to L929 fibroblast and breast cancer cells (MDA-MB-231).