A series of silsesquioxane-supported Phillips-type molecular catalysts for ethylene polymerization were synthesized by introducing various functional groups in proximity to monoalkylated Cr(III). They were moderately active in ethylene polymerization, while the performance was sensitive to the type of functional group. In particular, the presence of a lone pair near the active center was found to enhance the activity and expand the molecular weight distribution, which is plausibly due to alkylaluminum temporally captured by the lone pair. A similar result was never obtained by adding free molecules bearing a lone pair, and the fixation of the lone pair near the active site was essential. It was revealed that the design strategy based on the support functionalization can be transferred to SiO₂-supported chromium catalysts.

中文翻译：

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官能团对倍半硅氧烷负载的菲利普斯型催化剂乙烯聚合性能的影响

通过在单烷基化的Cr（III）附近引入各种官能团，合成了一系列倍半硅氧烷负载的Phillips型乙烯聚合分子催化剂。它们在乙烯聚合中具有中等活性，而性能对官能团的类型敏感。特别地，发现在活性中心附近存在孤对增强了活性并扩展了分子量分布，这可能是由于孤对在时间上捕获了烷基铝。通过添加带有孤对的游离分子从未获得过类似的结果，孤对在活性位点附近的固定是必不可少的。结果表明，基于载体功能化的设计策略可以转移到SiO _2上。负载的铬催化剂。