This work presents a general method for producing edge-modified graphene using electrophilic aromatic substitution. Five types of edge-modified graphene were created from graphene/graphite nanoplatelets sourced commercially and produced by ultrasonic exfoliation of graphite in N-methyl-2-pyrrolidone. In contrast to published methods based on Friedel–Crafts acylation, this method does not introduce a carbonyl group that may retard electron transfer between the graphene sheet and its pendant groups. Graphene sulphonate (G–SO3−) was prepared by chlorosulphonation and then reduced to form graphene thiol (G–SH). The modifications tuned the graphene nanoparticles’ solubility: G–SO3− was readily dispersible in water, and G–SH was dispersible in toluene. The synthetic utility of the directly attached reactive moieties was demonstrated by creating a “glycographene” through radical addition of allyl mannoside to G–SH. Chemical modifications were confirmed by FT-IR and XPS. Based on XPS analysis of edge-modified GNPs, G–SO3− and G–SH had a S:C atomic ratio of 0.3:100. XPS showed that a significant amount of carbon sp2 character remained after functionalisation, indicating little modification to the conductive basal plane. The edge specificity of the modifications was visualised on edge-modified samples of graphene produced by chemical vapour deposition (CVD): scanning electron microscopy of gold nanoparticles attached to G–SH samples, epifluorescence microscopy of a glycographene bioconjugate with a fluorescently tagged lectin, and quenched stochastic optical reconstruction microscopy (qSTORM) of thiol-reactive fluorophores on CVD G–SH samples. Microelectrochemistry of unmodified CVD graphene and dye-modified CVD G–SH showed no statistically significant difference in interfacial electron transfer rate (k0). This platform synthesis technology can allow pristine graphene, rather than graphene oxide or its derivatives, to be used in applications that require the superior mechanical or electronic properties of pristine graphene, including theranostics and tissue engineering. Electrophilic aromatic substitution produces edge-specific modifications to CVD graphene and graphene nanoplatelets that are suitable for specific attachment of biomolecules Electrophilic aromatic substitution produces edge-specific modifications to CVD graphene and graphene nanoplatelets that are suitable for specific attachment of biomolecules

中文翻译：

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通过亲电芳香取代对原始石墨烯进行边缘特异性修饰的通用途径

这项工作提出了一种使用亲电芳香取代生产边缘改性石墨烯的通用方法。五种类型的边缘改性石墨烯由商业采购的石墨烯/石墨纳米片制成，并通过在 N-甲基-2-吡咯烷酮中对石墨进行超声波剥离来生产。与基于 Friedel-Crafts 酰化的已发表方法相比，该方法不会引入可能阻碍石墨烯片及其侧基之间电子转移的羰基。石墨烯磺酸盐（G-SO3-）通过氯磺化制备，然后还原形成石墨烯硫醇（G-SH）。这些修改调整了石墨烯纳米粒子的溶解度：G-SO3- 易于分散在水中，而 G-SH 可分散在甲苯中。通过将烯丙基甘露糖苷自由基加成到 G-SH 来产生“糖石墨烯”，证明了直接连接的反应性部分的合成效用。通过 FT-IR 和 XPS 确认了化学修饰。基于边缘改性 GNP 的 XPS 分析，G-SO3− 和 G-SH 的 S:C 原子比为 0.3:100。XPS 显示功能化后仍然保留大量碳 sp2 特征，表明对导电基面的修改很小。修饰的边缘特异性在通过化学气相沉积 (CVD) 生产的石墨烯边缘修饰样品上可视化：附着在 G-SH 样品上的金纳米颗粒的扫描电子显微镜，带有荧光标记凝集素的糖石墨烯生物缀合物的落射荧光显微镜 CVD G-SH 样品上硫醇反应性荧光团的淬火随机光学重建显微镜 (qSTORM)。未改性的 CVD 石墨烯和染料改性的 CVD G-SH 的微电化学显示界面电子转移速率 (k0) 没有统计学上的显着差异。这种平台合成技术可以让原始石墨烯，而不是氧化石墨烯或其衍生物，用于需要原始石墨烯优异机械或电子特性的应用，包括治疗诊断学和组织工程。