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Partially fluorinated graphites synthesized at room temperature are capable of reversibly accommodating various molecules in the interlayer space. The structures and properties of these intercalation compounds depend on the fluorine content in the matrix and the nature of the guest. In this work, we compare the thermal stability and optical characteristics of (C2Fx)nwith x= 0.92 and 0.87, intercalated with acetonitrile and 2-butanone. Density functional theory calculations accompany experimental studies. It is shown that guest molecules prefer to be located over the sp2-carbon regions remaining in the partially fluorinated graphene layers. The 2-butanone molecule has stronger interactions with the layers due to its larger length, flexibility, and the presence of carbonyl oxygen. As a result, this guest leaves (C2Fx)nmatrixes at higher temperatures than acetonitrile. Different guest–host interactions cause a change in the electron excitations and photoluminescence of the fluorinated graphite intercalation compounds. In particular, the spectra are red-shifted when the matrices contain 2-butanone. This property can be used to create optical chemisensors based on partially fluorinated graphene layers.

Here, we study the dielectric properties of fluorinated graphites C2Fxwith different fluorine contents (x≈ 1.05, 0.85, and 0.60) and embedded bromine molecules by impedance spectroscopy. An analysis of the results using the Maxwell-Garnett approximation made it possible to estimate the contributions of the fluorinated graphite matrix and bromine guests to the dielectric permittivity of the compound. The permittivity of the C2Fxmatrix increases with decreasing fluorine content and does not depend on temperature. The change in the permittivity upon cooling/heating of the samples is provided by the polarization of bromine molecules Br2. The significant temperature-dependent dielectric response of C2F0.60is associated with the formation of bromine and polybromide ions, such as Br2–and Br3–, in the interlayer space of the matrix. The decrease in the permittivity at low temperature is explained by the freezing of the ion mobility.

Fluorination of graphite at room temperature allows producing graphite fluoride compounds with a controlled content of fluorine. Here we combine solid-state NMR spectroscopy and DFT calculations to study the structure and reveal the fluorine patterning in graphite fluorides C2Fxintercalated with acetonitrile. Two major chemical states of carbon, namely the atoms covalently bound to fluorine and the bare atoms, are detected by 13C MAS NMR irrespective of the degree of fluorination. The data indicate that although all graphene sheets were subjected to fluorination, the near-planar configuration is preserved. The interaction between host C2Fxmatrix and acetonitrile molecules is of van der Waals character. Decomposition of the 19F MAS NMR spectra reveals occurrence of at least six fluorine environments in each sample. By DFT calculations distinct 19F chemical shifts are attributed to isolated, end chain, “linked” (which include midchain, cyclic, and branched) CF groups and infinite CF arrays. The assignment is confirmed by 19F RFDR, which is sensitive to dipolar coupling. Analyzing the data for C2Fxsamples with different degrees of fluorination x, an evolution of the fluorine pattern is proposed. The reported calculated 19F NMR shielding parameters provide classification criteria for assignment of 19F NMR chemical shifts in fluorinated carbon materials.