Chemical reactivity of C–F bonds attached to graphene with diamines depending on their nature and location

Abstract

The attachment of fluorine to graphene is a facile means to activate the carbon bonds for subsequent covalent bonding to other molecules for the preparation of desired graphene derivatives. Therefore, an insight into the chemical reactivity of fluorinated graphene (FG) is very essential to enable precise control of the composition and structure of the final products. In this study, FG has been treated with various mass amounts of poly(oxypropylene)diamine (PEA) ranging from starvation to saturation to explore the dependence of a substitution reaction of diamines on the nature and location (attached onto the basal planes or along defects or edges) of C-F bonds. X-ray photoelectron spectroscopy directly tracked the atomic percentage of fluorine present and the carbon 1s bonding state, showing that the grafting ratio of diamines gradually increases with increased diamine mass ratio. The varying of the types and orientation of C-F bonds characterized by polarized attenuated total reflectance Fourier transform infrared spectroscopy indicates that "covalent" C-F bonds are more sensitive to the substitution reaction of diamines than ''semi-ionic'' C-F bonds, and the C-F bonds attached onto basal planes more preferably participate in the functionalization reaction of diamines than that of C-F bonded on non-coplanar regions (edges or defects). The one-dimensional expansion along the graphene c-axis shown by wide angle X-ray diffraction provides further evidence on the preferred functionalization reaction of C-F attached on the basal planes, resulting in a change of the average intersheet distance by various magnitudes.

Improving Compressive Strength of Aramid Fiber by Introducing Carbon Nanotube Derivates Grafted with Oligomers of Different Conformations and Controlling Its Alignment

“…Previous studies in our group have verified that CF bonds can react with various amino groups, and its reaction with N‐H on benzimidazole has also been reported . Interestingly, both primary amino groups at the end of molecular chains and secondary amino groups from benzimidazole units exist in PBIA.…”

C−N Coupling Reactions on Graphene with Aromatic Macromolecules and the Spatial Conformation of Grafted Macromolecules

“…Figure 2(a) shows the IR spectra of FG and the product after the one-step process at room temperature (denoted as FG-PABI-RT). Although the wide absorption band of CÀFb onds at around1 100 cm À1 is weakened, [10] there is no remarkableIRabsorptiono ft he amide groups (I and II bands at around 1650 and 1530 cm À1 ,r espectively)f or FG-PABI-RT.T his result suggests the failure of the graphene covalentm odification with aromatic polyamide withouta ccurate control. It might arise from the rapid and severe defluorination of FG caused by the specific solvent (DMAc) prior to the required reaction, which leads to the deficiency of reactive CÀFb onds according to our previousr esearch.…”

“…[9] However,t he main drawback of this route is the intricatea ssignment of oxygen-containing groups on GO, including carboxyl groups at the edges and epoxides out of the basal plane,w hich makes it at ough task to manipulate the related reactions. [10] Fluorinated graphene (FG), as toichiometric and well-defined graphene derivative with ah igh F/C ratio, has high reactivity becauseo ft he facile cleavage of axial CÀFb onds on original graphene, which makes it ap romisingc andidate as the precur-sor for graphene covalent modification. [11] In addition, owing to the unique attributes of CÀFb onds, FG is expected to initiate the reactions under milder conditions than the analogous one involving fluorobenzene.…”

Chemistry, properties, and applications of fluorographene

“…Ethylenediamine was the first nucleophilic compound, which was employed for the covalent functionalization of FG [110] . Since then, many groups investigated the reaction between amine-bearing compounds and FG [111] , [112] , [113] , [114] . In particular, Whitener et al [111] extensively studied the electrophilic character of FG through reactions between FG with various of amine-, alcohol- and sulfur-bearing compounds, which have high nucleophilicity.…”