Synthesis, functionalization and properties of incompletely condensed “half cube” silsesquioxanes as a potential route to nanoscale Janus particles
作者:Michael Z. Asuncion、Marco Ronchi、Haya Abu-Seir、Richard M. Laine
DOI:10.1016/j.crci.2009.10.007
日期:2010.1
Résumé Multiple literature reports describe the synthesis of [RSiO(OH)]4 or [RSiO(ONa)]4 compounds. Surprisingly, in the majority of cases the OH or ONa groups all lie on the same face of the cyclomers or half cubes. Consequently, it appears possible to couple R containing half cubes with R’ containing half cubes to form bi-functional (Janus) silsesquioxane cages or cubes. We report here synthesis of [PhSiO(ONa)]4 and [p-IPhSiO(ONa)]4 half cubes. We thereafter discuss efforts to react the [PhSiO(ONa)]4 salt with (R = Me, vinyl, and cyclohexyl) RSiCl3 in MeOH to produce the compounds PhSiO[OSi(OMe)2R]}4 species which were characterized using traditional spectroscopic procedures. These compounds were then subjected to acid catalyzed hydrolysis tohydrolytically remove the OMe groups to generate Janus cubes. While it is possible to isolate the target compounds, which were also characterized in detail, the yields were lower than expected perhaps because of competitive hydrolytic cleavage of the Si-O-SiR(OMe)2 linkage.
多个文献报道描述了 [RSiO(OH)]4 或 [RSiO(ONa)]4 化合物的合成。令人惊讶的是,在大多数情况下,OH或ONa基团都位于环聚体或半立方体的同一面上。因此,似乎有可能将含有 R 的半立方体与含有 R' 的半立方体偶联以形成双功能 (Janus) 倍半硅氧烷笼或立方体。我们在此报告了 [PhSiO(ONa)]4 和 [p-IPhSiO(ONa)]4 半立方体的合成。此后,我们讨论了 [PhSiO(ONa)]4 盐与(R = Me、乙烯基和环己基)RSiCl3 在 MeOH 中反应生成化合物 PhSiO[OSi(OMe)2R]}4 物种的努力,这些化合物使用传统方法进行了表征光谱程序。然后对这些化合物进行酸催化水解,水解去除 OMe 基团,生成 Janus 立方体。虽然可以分离出目标化合物,并对其进行了详细表征,但收率低于预期,这可能是由于 Si-O-SiR(OMe)2 键的竞争性水解裂解所致。