Abstract：
Enhanced conversion of carbon dioxide (CO2) for cycloaddition with epoxide derivatives is highly desired in organic synthesis and green chemistry, yet it is still a challenge to obtain satisfactory activity under mild reaction conditions of temperature and pressure. For this purpose, an unexploited strategy is proposed here by incorporating near-infrared (NIR) photothermal properties into multicomponent catalysts. Through the electrostatic adsorption of Co- or Ce-substituted polyoxometalate (POM) clusters on the surface of graphene oxide (GO) with covalently grafted polyethyleneimine (PEI), a series of composite catalysts POMs@GO-PEI are prepared. The structural and property characterizations demonstrate the synergistic advantages of the catalysts bearing Lewis acids and bases and local NIR photothermal heating from the GO matrix for dramatically enhanced CO2 cycloaddition. Noticeably, while the turnover frequency increases up to 2718 h-1, the heterogeneous catalysts exhibit photothermal stability and recyclability. With this method, the onsite NIR photothermal transformation becomes extendable to more green reaction processes.
摘要：
在有机合成和绿色化学中，非常需要二氧化碳（CO2）与环氧化物衍生物进行环加成的转化。然而，在温和的温度和压力反应条件下获得令人满意的活性仍然是一个挑战。为此,通过将近红外（NIR）光热性能引入多组分催化剂中，提出了一种未开发的策略。通过共价接枝的聚乙烯亚胺（PEI）在氧化石墨烯（GO）表面静电吸附Co或Ce取代的多金属氧酸盐（POM）簇，制备了一系列复合催化剂POMs@GO-PEI。结构和性能表征表明，带有路易斯酸和碱的催化剂以及来自GO基质的局部NIR光热加热具有协同优势，可显着增强CO2环加成。值得注意的是，当周转频率增加到2718h-1时，非均相催化剂表现出光热稳定性和可回收性。使用这种方法，现场近红外光热转换变得可扩展到更绿色的反应过程。
