不完全缩合七苯基三羟基POSS的合成及表征

Synthesis and Characterization of Incompletely Condensed Heptaphenyltrisilanol-POSS

以苯为溶剂,40%苄基三甲基氢氧化铵的甲醇溶液为催化剂,苯基三氯硅烷水解缩合得到笼状八苯基多面低聚倍半硅氧烷,进一步在四乙基氢氧化铵(35%水溶液)的作用下,以四氢呋喃为溶剂,通过顶点-打开法合成不完全缩合的多面低聚倍半硅氧烷。利用1H、13C、29Si-NMR、FT-IR、元素分析、MALDI-TOF质谱等技术对产物的结构进行了表征,并采用TGA对其热稳定性进行了研究。结果表明,反应主产物为不完全缩合的七苯基三羟基多面低聚倍半硅氧烷,其初始分解温度(失重5%(wt))为516.1℃,热稳定性良好。与以往的合成方法相比,该法显著缩短了反应时间,并提高了产率,从而为POSS在纳米杂化材料领域的应用打下了基础。

Using the tetrahydrofuran （THF） as solvent and 40% benzyl trimethyl ammonium hydroxide methanol solution as catalyst, the octaphenyl polyhedral oligomeric silsesquioxane （（C6H5）8T8） was synthesized via the hydrolytic condensation of phenyltrichlorosilane. The obtained （C6H5）8T8 was proved to be precise and pure by FT-IR and 29Si-NMR; then with the help of aqueous tetraethyl ammonium hydroxide （TEAOH） and using the THF as solvent, via the corner-opening reaction; the synthesized （C6Hs）sTs was reacted into the incompletely condensed POSS. In order to suppress the by-product reactions, the comer-opening reaction temperature, time and the amount of catalyst used should be well controlled. The structure of the corner-opening reaction product was determined and validated by 1H-NMR, 13C-NMR, FT-IR, elementary analysis and MALDI-TOF MS. The results indicate that the main product of the corner-opening reaction is heptaphenyltrisilanol-POSS, and its initial decomposing temperature analyzed by TGA is 516.1℃ （5%（wt） weight loss）, which suggests that the obtained heptaphenyltrisilanol-POSS has good thermal stability. Compared with literature works, the reaction time of this work is much shorter and thus the yield is increased, which would make the POSS be more useful in the syntheses of organic-inorganic hybrid materials.