Combining polymer-bound catalyst with polymeric substrate for reproducible pH oscillations in palladium-catalysed oxidative carbonylation of alkynes
Combining polymer-bound catalyst with polymeric substrate for reproducible pH oscillations in palladium-catalysed oxidative carbonylation of alkynes
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DOI：
10.1016/j.eurpolymj.2018.10.038
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发表时间：
2018-12-01
影响因子：
6
通讯作者：
Novakovic, Katarina
中科院分区：
文献类型：
--
作者：
Isakova, Anna;Parkes, George E.;Novakovic, Katarina
钯催化的炔氧化羰基化（PCOC）是用于构建智能脉动聚合物系统的有前途的引擎，因为它已经证明（在某些配置中）在间歇反应器中长达一个月的监测中pH和氧化还原电位的持续规则振荡。聚合物负载的钯催化剂的最新发展已经证明了这种反应的全部能力-在经历体积振荡的大凝胶中，同时释放药物负载。在这项工作中，我们证明了可重复的振荡（超过100小时的持续时间）在脯氨酸官能化壳聚糖钯系统（Chi-Pro-Pd），同时使用小分子（苯乙炔）和聚合物（聚乙二醇化二炔）基板，为第一次。此外，通过用脯氨酸配体官能化壳聚糖，我们大大减少了卤化物介导的钯浸出，这在非官能化壳聚糖-钯催化剂（Chi-Pd）中容易发生。这两个系统的振荡模式确认需要制造功能化壳聚糖支持，以提高催化剂的可重复使用性和钯的损失最小化。
Palladium-catalysed oxidative carbonylation (PCOC) of alkynes is a promising engine for building smart pulsatile polymeric systems, as it has demonstrated (in certain configurations) sustained regular oscillations in pH and redox potential for up to one month of monitoring in a batch reactor. Recent developments in polymer-supported palladium catalysts have demonstrated the full capacity of this reaction - in a macrogel that experienced oscillations in volume, while releasing a drug load. In this work, we demonstrate reproducible oscillations (more than 100 h duration) in a proline-functionalised chitosan-palladium system (Chi-Pro-Pd), using both small molecule (phenylacetylene) and polymeric (pegylated dialkyne) substrate, for the first time. Moreover, by functionalising chitosan with proline ligands, we dramatically reduced halide-mediated leaching of palladium, which readily occurred in non-functionalised chitosan-palladium catalysts (Chi-Pd). Oscillatory patterns for both systems confirm the need for fabricating functionalised chitosan supports to improve catalyst reusability and minimise loss of palladium.