Iron-mediated extensive amination of graphene-based nanomaterials

Functionalization of graphene and its derivatives has become of paramount significance to prepare high value-added nanomaterials and unlock their coupling with functional molecules, polymers, nanoparticles and surfaces. This work presents a new, mild functionalization of graphene derivatives to insert NH2 groups (up to ∼10 % N content) using O-(mesyl)-hydroxylammonium triflate ([MsONH3]+[OTf]-) in the presence of ferrocene in a polar medium. Remarkably, this reaction affords amination at both the edges and basal plane of graphene nanoplatelets (GNPs) without introducing new structural defects. Moreover, this protocol also works well on graphene oxide (GO) and reduced GO (RGO), yielding layers with a conspicuous percentage of nitrogen in their structures (7-10 %). Aminated GNPs, GO and RGO samples have been thoroughly characterized by several spectroscopic techniques and their functionalization reactions theoretically modelled via DFT calculations. The results support a free radical course of the reaction leading to the insertion of both aliphatic and aromatic amines localized at the edges or within the basal plane of the materials. The resulting functionalization of GNPs with NH2 groups increases the dispersibility of this material in water, paving the way to the preparation of novel hydrophilic graphene-based nanoassemblies based on a covalent chemistry.