Covalent Functionalization by Cycloaddition Reactions of Pristine Defect-Free Graphene

Abstract

Based on a low-temperature scanning tunneling microscopy study, we present a direct visualization of a cycloaddition reaction performed for some specific fluorinated maleimide molecules deposited on graphene. Up to now, it was widely admitted that such a cycloaddition reaction can not happen without pre-existing defects. However, our study shows that the cycloaddition reaction can be carried out on a defect-free basal graphene plane at room temperature. In the course of covalently grafting the molecules to graphene, the sp conjugation of carbon atoms was broken, and local sp bonds were created. The grafted molecules perturbed the graphene lattice, generating a standing-wave pattern with an anisotropy which was attributed to a (1,2) cycloaddition, as revealed by T-matrix approximation calculations. DFT calculations showed that while both (1,4) and (1,2) cycloadditions were possible on free-standing graphene, only the (1,2) cycloaddition could be obtained for graphene on SiC(0001). Globally averaging spectroscopic techniques, XPS and ARPES, were used to determine the modification in the elemental composition of the samples induced by the reaction, indicating an opening of an electronic gap in graphene.

Structure of graphene and its disorders: a review

“…However, in most cases the properties of graphene are supposed to be tailored for satisfying different requirements in industries. Tuning properties of graphene can be realized by several defects modulations approaches, including particle irradiation [326–328], thermal annealing [329,330], chemical reaction [331,332] and strain treatment [333,334], as summarized in Table 2.…”

“…Daukiya et al [332] successfully performed cycloaddition reactions on graphene by depositing maleimide derivative molecules at room temperature. Experimental results indicate that both (1,4) and (1,2) cycloadditions are possible on freestanding graphene, but only the (1,2) cycloaddition could be activated for SiC (0001)-supported graphene.…”

Photopolymerization of maleimide perfluoropolyalkylethers without a photoinitiator

“…Maleimides containing pentafluoro and trifluoro groups on aromatics were copolymerized with vinyl ethers by Hendlinger et al whereas Jain et al copolymerized N ‐(4‐fluoro phenyl) maleimide with methyl methacrylate. Daukiya et al showed the use of N ‐(3,4‐trifluoro phenyl) maleimide with highly nonreactive graphene. Fluorinated oligomers with maleimides were first reported by Beaune et al with C 6 F 13 chains .…”

Microcontact Printing Patterning of an HOPG Surface by an Inverse Electron Demand Diels–Alder Reaction

“…[7][8][9][10] For example, Haddon and co-workerss howed that graphite/graphenec an serve as a diene by reacting with tetracyanoethylene (TCNE) at room temperature. [7][8][9][10] For example, Haddon and co-workerss howed that graphite/graphenec an serve as a diene by reacting with tetracyanoethylene (TCNE) at room temperature.…”

“…[7] The Braunschweig group showed that cyclopentadiene can covalently react with ag raphene surface under high pressure Diels-Alder conditions. [10] Inverse electron demand Diels-Alder reactions (IEDDA) have been the subjecto fc onsiderable interest in biorthogonalc onjugations. [9] More recently, Simon and co-workersd emonstrated the direct visualizationo ft he covalent cycloaddition of maleimide derivatives on the defect-free basal graphene plane by scanning tunneling microscopy.…”