New types of cyclo- and polyphosphazenes that bear pyridine side groups have been synthesized. The reactions of 2-(2-aminoethyl)pyridine and 2-((2-aminoethyl)amino)-5-nitropyridine with (NPCl2)3 were complex, with chlorine replacement being complicated by degradation and the formation of mixtures. However, the use of electron withdrawing cosubstituents, such as phenoxy or trifluoroethoxy groups, allows straightforward chlorine replacement reactions induced by the aminoalkylpyridines to occur. The mono(alkylpyridine)-substituted cyclotriphosphazenes N3P3(OC6H5)5(NHCH 2CH2(C5H4N)) (1) and N3P3(OC6H5)5(NHCH 2CH2NH(C5H3N)NO2) (2) were synthesized as model compounds for high polymers. Polyphosphazenes of the general formula [NP(OCH2CF3)x(NHCH2- CH2(C5H4N))y]n were prepared by exposing [NPCl2]n to sodium trifluorethoxide and 2-(2-aminoethyl)pyridine in a two-step reaction. All compounds were characterized by 1H, 13C, 31P NMR spectroscopy, and elemental analysis. The cyclic trimers were also identified by mass spectrometry. Molecular weight estimations of the polymers were carried out by gel permation chromatography, and glass transition temperatures were determined by differential scanning calorimetry.
|Original language||English (US)|
|Number of pages||4|
|State||Published - 1994|
All Science Journal Classification (ASJC) codes
- Inorganic Chemistry