Functionalization of graphene: does the organic chemistry matter?

Abstract

Reactions applying amidation- or esterification-type processes and diazonium salts chemistry constitute the most commonly applied synthetic approaches for the modification of graphene-family materials. This work presents a critical assessment of the amidation and esterification methodologies reported in the recent literature, as well as a discussion of the reactions that apply diazonium salts. Common misunderstandings from the reported covalent functionalization methods are discussed, and a direct link between the reaction mechanisms and the basic principles of organic chemistry is taken into special consideration.

Understanding and controlling the covalent functionalisation of graphene

“…Most commonly, carboxylic acids, which may be adventitious or deliberate by-products of oxidation (see below), are subjected to esterification or amidification reactions with alcohols and amines, respectively. 36 The edges of graphene flakes, or the grain boundaries within polycrystalline layers, which may be viewed as 1D defects within the 2D material, provide many correlated sites for reaction. The carbon framework of the core of the flake retains its sp 2 hybridisation, so properties are not compromised, although doping and spin effects are under investigation.…”

Functionalization of Graphene Oxide with Porphyrins: Synthetic Routes and Biological Applications

“…The first step in the diazotization of an amino reagent leading to the diazonium salt is crucial for the successful attachment of a desired group in GO framework (Scheme 6). [113] In the presence of a GO sheet, a single electron transfer (SET) may occur yielding an aryl radical accompanied by nitrogen extrusion. Then, the combination of the aryl radical with the GO radical cation affords the desired intermediate.…”

Functionalization of Carbon Nanomaterials for Biomedical Applications

“…A good example of free radical addition is the diazotization reaction. This reaction proceeds as following: generation of the diazonium salt from the amino reagent using a nitrite species, single electron transfer between the diazonium salt and the graphene material, radical addition, formation of the phenol and adsorption of phenol onto the graphene sheet [41,164]. Wei et al functionalized rGO with p-aminobenzoic acid, which formed the diazonium ions through diazotization with a wet chemical method.…”