Pavel A. Khavrel

Synthesis and characterization of difluoromethylene-homo[60]fullerene, C60(CF2)

Refluxing of the o-DCB solution of C60 with CF2ClCOONa and 18-crown-6 leads to formation of C60(CF2)n (n = 1-3); the monoadduct C60(CF2) has been found to consist of the main [6,6]- and minor [5,6]-isomers, both having an open structure.

Regioselective near-equatorial chlorination of Cs-C70(CF3)8

The chlorination of Cs-C70(CF3)8 by ICl occurs at near-equatorial [5,6] bond in agreement with quantum chemical predictions; structure of the synthesized Cs-C70(CF3)8Cl2 was proven by 19F NMR spectroscopy and single crystal X-ray crystallography.

The former “C60F16” is actually a double-caged adduct: (C60F16)(C60)

X-ray diffraction study of the substance originally believed to be C(60)F(16) reveals a double-caged structure, (C(60)F(16))(C(60)); MALDI mass spectra, 19F NMR spectral data and reasons for stability are discussed.

Mass spectrometric identification of multicage fullerene cycloadducts

Multicage fullerene cycloadducts have been detected by MALDI mass spectrometry; they have been found as admixtures in the products of reactions of the trifluoromethylation of fullerene samples doped with metallic sodium, the reaction between fullerenes and a mixture of trifluoromethylfullerenes, and the synthesis of fulleroproline esters. As a result, over 75 new compounds of this type have been identified. The optimization of the synthesis procedures and chromatographic fractionation allowed us to extract five compounds in the pure form: (C60)2(CF2)2(CF3)8, (C60)2(CF2)2(CF3)3C2F5, (C60)2(CF2)2(CF3)5C2F5, (C60)2(CF2)2(CF3)2O, and C60CH2N(CH2C60)CCOOtBu. Chemical structures of two of them, proposed on the basis of post source decay mass spectra, have been further confirmed by NMR spectra.

Synthesis and structure of cycloperfluoroalkylated derivatives of C70, C70(C2F4) and C70(C4F8)n, n = 1–6

The addition reactions of biradicals thermally generated from 1,2-C2F4I2 or 1,4-C4F8I2 were applied to functionalize C70 fullerene. The mixtures of C70(C2F4)m and C70(C4F8)n products were separated by HPLC resulting in several individual compounds. Molecular structures of new cycloperfluoroalkylated C70, C70(C2F4), C70(C4F8) (two isomers), C70(C4F8)2, C70(C4F8)4, C70(C4F8)5 (two isomers), and C70(C4F8)6 (two isomers) were determined by single crystal X-ray diffraction and discussed in terms of their addition patterns and relative energies of their formation.

Preparation and structures of [6,6]-open difluoromethylene[60]fullerenes: C60(CF2) and C60(CF2)2.

Difluoromethylenation of C60 with thermally decomposed CF2ClCO2Na provides novel C60(CF2) and C60(CF2)2 compounds with unique [6,6]-open structures. A theoretical survey of CF2 derivatives of C60 demonstrates that carbon cage opening can be controlled via charging of the molecule and that the thermodynamically preferable structures combine the trend to form open isomers with the compactness of the addition motifs, which results in the formation of windows in the fullerene cage.

Fluorinated microwave exfoliated graphite oxide: structural features and double layer capacitance

ABSTRACT Fluorinated microwave exfoliated graphite oxide (MEGO) samples containing 5.7–29.3 at.% of fluorine were prepared by gas phase treatment of MEGO with XeF2. According to X-ray photoelectron spectroscopy and infrared spectroscopy data, fluorination of MEGO occurs at C=C bonds while leaving the oxygenated domains intact, and increases the O/C ratio. Cyclic voltammetry studies of fluorination effect on double layer capacitance of MEGO shows 67% growth of its specific capacitance, making such and related carbon materials prospective for supercapacitor applications.

Thermodynamic functions for the formation of isomeric CF3 adducts of C70 and C84

ABSTRACT Gas-phase formation enthalpies and Gibbs energies of formation (ΔfH°m; ΔfG°m) of trifluoromethylderivatives of fullerenes C70 and C84 are calculated at the DFT (density functional theory) level of theory. The approach employs homodesmic (HD) transtrifluoromethylation reactions and experimental thermochemical data on C60, C70, C84 and S6-C60(CF3)12.