We investigated solvent effects on the acid-catalyzed deallylation of organoallylsilane precursors to identify mild solâgel polymerization conditions. Organoallylsilanes are expected to be alternative precursors for preparation of functionalized organosilica hybrids but they undergo solâgel polymerization with difficulty due to their low reactivity towards hydrolysis. Solâgel polymerization of model organoallylsilane precursors was conducted in various organic solvents and deallylation was monitored by 1H NMR spectroscopy. The nature of the solvent was found to strongly influence the deallylation rate and a significant correlation was observed between reaction rate and solvent basicity, which suggests that proton activity is a key factor in enhancing the reaction rate. In particular, acetonitrile was found to most effectively enhance the rate, and it accelerated the formation of a spirobifluorene-bridged organosilica hybrid film from its allylsilane precursor under a mild acidic condition. This key finding can be generally utilized for the preparation of organoallylsilane-derived highly functionalized organosilica hybrids.
我们研究了溶剂对酸催化有机烯丙基
硅烷前体脱烯丙基反应的影响,从而确定了温和的溶胶聚合条件。有机烯丙基
硅烷有望成为制备功能化有机
硅杂化物的替代前体,但由于其
水解反应性低,很难进行溶胶聚合。在各种有机溶剂中对模型有机烯丙基
硅烷前体进行了溶胶聚合反应,并通过 1H NMR 光谱监测脱烯丙基反应。研究发现,溶剂的性质对脱烯丙基速率有很大影响,反应速率与溶剂碱性之间存在显著的相关性,这表明质子活性是提高反应速率的关键因素。其中,
乙腈能最有效地提高反应速率,并能在弱酸性条件下加速烯丙基
硅烷前体形成螺二
芴桥接有机
硅杂化膜。这一重要发现可普遍用于制备有机烯丙基
硅烷衍生的高功能化有机
硅杂化物。