Nicks Joshua, Foster Jonathan A
Department of Chemistry, University of Sheffield, Sheffield, UK.
Nanoscale. 2022 Apr 21;14(16):6220-6227. doi: 10.1039/d2nr00346e.
The liquid exfoliation of layered metal-organic frameworks (MOFs) to form nanosheets (MONs) exposes buried functional groups making them useful in a range of sensing and catalytic applications. Here we show how high yielding click reactions can be used post-exfoliation to systematically modify the surface chemistry of MONs allowing for tuning of their surface properties and their use in new applications. A layered amino-functionalised framework is converted through conventional post-synthetic functionalisation of the bulk MOF to form azide functionalised frameworks of up to >99% yield. Ultrasonic liquid exfoliation is then used to form few-layer nanosheets, which are further functionalised through post exfoliation functionalisation using Cu(I)-catalysed azide-alkyne cycloaddition reactions. Here we demonstrate the advantages of post-exfoliation functionalisation in enabling: (1) a range of functional groups to be incorporated in high yields; (2) tuning of nanosheet surface properties without the need for extensive recharacterisation; (3) the addition of fluorescent functional groups to enable their use in the sensing of hazardous nitrobenzene. We anticipate that the versatility of different functional groups that can be introduced through high yielding click reactions will lead to advances in the use of MONs and other 2D materials for a variety of applications.
层状金属有机框架（MOFs）的液相剥离以形成纳米片（MONs），会暴露出其隐藏的官能团，这使得它们在一系列传感和催化应用中很有用。在此，我们展示了高产率的点击反应如何在剥离后用于系统地修饰MONs的表面化学性质，从而实现对其表面性质的调控，并将其应用于新的领域。通过对块状MOF进行传统的合成后功能化，将一种层状氨基功能化框架转化为叠氮化物功能化框架，产率高达>99%。然后使用超声液相剥离法形成少层纳米片，通过使用铜（I）催化的叠氮化物-炔烃环加成反应进行剥离后功能化，对其进一步功能化。在此，我们展示了剥离后功能化的优势，包括：（1）以高产率引入一系列官能团；（2）无需进行广泛的重新表征即可调控纳米片的表面性质；（3）添加荧光官能团以使其可用于危险硝基苯的传感。我们预计，通过高产率点击反应可以引入的不同官能团的多功能性，将推动MONs和其他二维材料在各种应用中的发展。
