Halbig Christian E, Fels Felix, Wei Shenquan, Schusterbauer Robert, Donskyi Ievgen, Heinrich Markus R, Eigler Siegfried
Freie Universität Berlin, Altensteinstraße 23a, 14105, Berlin, Germany.
Department Chemie und Pharmazie, Pharmazeutische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany.
Angew Chem Int Ed Engl. 2025 Jun 17;64(25):e202504482. doi: 10.1002/anie.202504482. Epub 2025 May 10.
Functionalization of graphene derivatives is a common approach to tune material properties for use in various applications. Because of the low reactivity of the unsaturated carbon lattice of graphene, not only are few chemical approaches suitable for successful functionalization, such as those involving highly reactive in situ formed radical species or nitrene and carbene compounds, but also the degree of functionalization is usually limited, modifying only a few percent of the carbon atoms. Typically, uncontrolled side reactions such as homocoupling and oligomerization of newly introduced functional groups can occur instead of direct coupling to the carbon lattice. We want to turn this unwanted side reaction into an advantage and use intentionally formed covalent dendrimeric oligophenylene structures for secondary functionalization. We show that these oligomeric structures can be grown to specific thicknesses and used for further functionalization with bromomethyl groups at high density on the surface. This functionalization opens further avenues for subsequent nucleophilic substitution, as exemplified by the introduction of versatile azide, nitrile, and phosphonate groups. The results presented here are not only applicable to large oligophenylene structures, but also demonstrate that, in principle, single aryl moieties on graphene of any size and density can be successfully functionalized.
石墨烯衍生物的功能化是一种调整材料性能以用于各种应用的常用方法。由于石墨烯不饱和碳晶格的低反应活性，不仅很少有化学方法适用于成功的功能化，例如那些涉及高反应活性的原位形成自由基物种或氮烯和卡宾化合物的方法，而且功能化程度通常也很有限，仅修饰百分之几的碳原子。通常，新引入的官能团会发生诸如均偶联和低聚等不受控制的副反应，而不是直接与碳晶格偶联。我们希望将这种不需要的副反应转化为优势，并使用有意形成的共价树枝状低聚苯撑结构进行二次功能化。我们表明，这些低聚结构可以生长到特定厚度，并用于在表面高密度地进一步用溴甲基进行功能化。这种功能化为后续的亲核取代开辟了更多途径，例如引入通用的叠氮基、腈基和膦酸酯基。这里展示的结果不仅适用于大型低聚苯撑结构，还表明原则上，任何尺寸和密度的石墨烯上的单个芳基部分都可以成功地进行功能化。
