Diels–Alder Reaction of Anthranilic Acids: A Versatile Route to Dense Monolayers on Flat Edge and Basal Plane Graphitic Carbon Substrates

Abstract

Methods that reliably yield monolayers of covalently anchored modifiers on graphene and other planar graphitic materials are in demand. Covalently bonded groups can add functionality to graphitic carbon for applications ranging from sensing to supercapacitors and can tune the electronic and optical properties of graphene. Limiting modification to a monolayer gives a layer with well-defined concentration and thickness providing a minimum barrier to charge transfer. Here we investigate the use of anthranilic acid derivatives for grafting aryl groups to few layer graphene and pyrolyzed photoresist film (PPF). Under mild conditions, anthranilic acids generate arynes, which undergo Diels-Alder cycloadditions. Using spectroscopy, electrochemistry, and atomic force microscopy, we demonstrate that the reaction yields monolayers of aryl groups on graphene and PPF with maximum surface coverages consistent with densely packed layers. Our study confirms that anthranilic acids offer a convenient route to covalent modification of planar graphitic carbons (both basal and edge plane materials).

Covalent functionalization of 1D and 2D sp2-carbon nanoallotropes – twelve years of progress (2011–2023)

“…The Diels-Alder cycloaddition of arynes was frequently employed as the covalent modification of FLG. 187 For instance, anthranilic acid was used for the aryne precursor (via a thermal loss of N 2 and CO 2 ). Similarly, rGOs of lower and Fig.…”

“…The Diels–Alder cycloaddition of arynes was frequently employed as the covalent modification of FLG. 187 For instance, anthranilic acid was used for the aryne precursor ( via a thermal loss of N 2 and CO 2 ). Similarly, rGOs of lower and higher O-content were functionalized via a Diels–Alder reaction with maleimide, and the reaction was studied both theoretically and experimentally.…”

Functionalization of Carbon Surfaces Using the Copper-Catalyzed Diels–Alder Reaction

“…The Diels–Alder reaction is an efficient alternative method to functionalize carbon materials, with several reviews available on the subject. − Interestingly, work carried out by Haddon et al shows that graphite and graphene interfaces can act as a diene or a dienophile in Diels–Alder reaction; similar observations have been made by Abetz et al using carbon nanotubes . However, despite its efficiency and versatility, the surface-based Diels–Alder reaction generally requires long reaction times, up to a few days, − and the use of elevated temperatures to drive the reaction successfully. − The use of specific solvents, such as deep eutectic solvents, microwaves, or ultrasonication have all successfully accelerated the functionalization rate and thus made this surface reaction of higher utility.…”

Spontaneous Decarboxylation of Ferrocenecarboxylate using 1,4‐Benzoquinone as Oxidant: Application to the Chemical Grafting of Glassy Carbon Surfaces

“…Hence, the covalent modification of carbon surfaces without electrochemical induction, has become a relevant matter that has been used to modify a wide variety of carbonaceous materials [3] . This kind of covalent modification or chemical grafting has been mainly explored in the case of the spontaneous decomposition of aryldiazonium cations, [4–6] however, other reactions have been also documented in literature, for example, in the case of amines, [7,8] ammonia, [9] unsaturated compounds like alkenes and alkynes [10–12] and Diels‐Alder reactions [13,14] . Other less explored examples of chemical grafting reactions are the spontaneous decomposition of alkynyl lithium compounds [15] and the decomposition of mixtures of strong carboxylic acids with its conjugated base [16] .…”

“…[3] This kind of covalent modification or chemical grafting has been mainly explored in the case of the spontaneous decomposition of aryldiazonium cations, [4][5][6] however, other reactions have been also documented in literature, for example, in the case of amines, [7,8] ammonia, [9] unsaturated compounds like alkenes and alkynes [10][11][12] and Diels-Alder reactions. [13,14] Other less explored examples of chemical grafting reactions are the spontaneous decomposition of alkynyl lithium compounds [15] and the decomposition of mixtures of strong carboxylic acids with its conjugated base. [16] This kind of processes are of great interest in the sense that the substrate not necessarily must be on the form of a compact material, but it can be also on the form carbon powders and non-conductive materials like polymers and biopolymers.…”