Repurposing of oxazolone chemistry: gaining access to functionalized graphene nanosheets in a top-down approach from graphite

Abstract

Solvent-free 1,3-dipolar cycloaddition reactions of graphite flakes and mesoionic oxazolones lead to the direct functionalization and delamination of graphite flakes into few layers of graphene nanosheets.

Understanding and controlling the covalent functionalisation of graphene

“…All the graphitic nanomaterials are susceptible to 1,3-dipolar cycloadditions, using azomethine ylides 45 (the Prato reaction), ozone, or oxazolones. 46 Graphene may also undergo Diels-Alder (DA) cycloadditions; 47 interestingly, these reactions show the classic reversibility of DA reactions, and the graphene may react as either diene or dienophile. 48 As an alternative to these neutral-graphene reactions, anionic graphene sheets can be prepared by doping with group 1 metals, either directly or via charge transfer agents.…”

“…(a) Comparison of grafting stoichiometries between XPS and TGA, based on reports in which both techniques are used on the same sample, 7,8,14,16,25,32,56 (red line, linear fit; black dashed line, equivalence of TGA and XPS measurements). (b) Molecular weight of grafted moiety versus degree of functionalisation (R/C, left) and grafting stoichiometry (C/R, right) and, categorised by reaction type: organo-radical additions 5,7,8,11,12,14,16,17,57,58 (black, diazonium/carbene/nitrene), halogenation 40,[59][60][61][62] (green), plasma-hydrogenation 63 ( puce), cycloadditions 45,46,56,[64][65][66] (red), reductive functionalisation 21,22,[24][25][26]28,29,32,33,35,67 (blue), thermochemical functionalisation 34 (magenta), and oxidation (orange). Limits for oxidation estimated from typical maximum limiting stoichiometry of C 8 O 4 H 5 from Pei et al 68 between 16 Da (epoxide) and 33 Da (carboxyl), with the lower limit for degree of oxidation from hydroxylation via oxo-graphene.…”

Intracellular Fate and Impact on Gene Expression of Doxorubicin/Cyclodextrin-Graphene Nanomaterials at Sub-Toxic Concentration

“…Pristine graphene (i.e., graphene in its original, unmodified form) has many remarkable properties but it is unable to be dispersed in water, making exploitation of its unique features challenging and less explored compared to its derivatives, that are more dispersible in aqueous medium, stable in physiological conditions, and further tunable for a wide range of applications, due to host functional groups [11,12]. G can differ on the basis of (i) synthetic approaches adopted for their preparation; (ii) not being homogeneous nature (several oxidation states, different lateral sizes and number of layers, colloidal stability, etc.…”

Heteroatom Promoted Cycloadditions for Graphene

“…The sp 2 framework renders graphene an interesting reactant for organic reactions. Among them, we can highlight: the addition of aryl diazonium salts, alkylation, 1,3 dipolar cycloadditons, [2+2] cycloadditions, [2+1] cycloadditions . and the Diels‐Alder reactions, where graphene can be either diene or dienophile .…”