Controlled Functionalization of Graphene Layers

Abstract

Controlled functionalization of graphene layers is one of the most important research objectives in the material chemistry. A well established procedure is the oxidation with strong acids and oxidizing agents often in harsh and dangerous reaction conditions giving products of unknown precise structure. In this chapter, the controlled functionalization of graphene layers with a derivative of serinol is presented, avoiding toxic reagents and dangerous reaction conditions. The derivative is the bio‐based serinol pyrrole, obtained through the neat reaction of serinol with 2,5‐hexanedione; the graphitic substrate was high surface area graphite (HSAG) with high‐shape anisotropy. The functionalization reaction, characterized by a 85% atomic efficiency (water is the only by‐product), evolved with high yields leading to functionalized graphene layers through the controlled introduction of oxygen and nitrogen‐containing functional groups. Sustainable processes were adopted, such as ball milling and heating. The mechanism pathway, the characterization of HSAG and reaction products through a wide range of analytical methods, some successful applications of the adducts are discussed in this chapter. The functionalization left the bulk crystalline structure of the layers substantially unaltered. Stable dispersions in water and eco‐friendly solvents were prepared

Facile and sustainable functionalization of graphene layers with pyrrole compounds

“…As reported in the introduction, SP has been shown able to form stable adducts with graphitic substrates [20][21][22]62]. It was commented [21,22] that SP is a Janus molecule, that is a molecule with two faces.…”

“…It was commented [21,22] that SP is a Janus molecule, that is a molecule with two faces. Such a definition, which comes from the Roman god Janus, has been used in the scientific literature to indicate particles with at least two physically or chemically different surfaces [63,64] and molecules with two moieties, typically one hydrophobic and the other hydrophilic, as in the case of colloids [65] and block copolymers [66].…”

“…Such a definition, which comes from the Roman god Janus, has been used in the scientific literature to indicate particles with at least two physically or chemically different surfaces [63,64] and molecules with two moieties, typically one hydrophobic and the other hydrophilic, as in the case of colloids [65] and block copolymers [66]. SP was used to functionalize sp 2 carbon allotrope [20][21][22]62] relying on the interaction of the pyrrole ring the with aromatic substrate. Indeed, the Paal Knorr reaction changes the hybridization of the nitrogen atom, from sp 3 in the amino group, to sp 2 in the aromatic pyrrole ring.…”

“…The polymeric nature of graphene layer with the six atoms aromatic ring as the repeating unit is responsible for such exceptional properties. Hence, main objectives of graphene synthesis [8][9][10][11][12] and functionalization [8,[13][14][15][16][17][18][19][20][21][22][23] are to obtain and preserve such structure.…”

“…Serinol pyrrole has been then used as the heterocyclic molecule for the functionalization of sp 2 carbon allotropes [20] and of graphene layers among them. Very high functionalization yield was reported and stable water dispersions of the carbon materials were obtained [21,22]. The high efficiency of the functionalization reaction paved the way to explore the reaction of the carbon allotropes with pyrrole compounds other than serinol pyrrole.…”