Author/Authors :
Goryunkov، نويسنده , , Alexey A. and Kareev، نويسنده , , Ivan E. and Ioffe، نويسنده , , Ilya N. and Popov، نويسنده , , Alexey A. and Kuvychko، نويسنده , , Igor V. and Markov، نويسنده , , Vitaliy Y. and Goldt، نويسنده , , Ilya V. and Pimenova، نويسنده , , Anna S. and Serov، نويسنده , , Mihail G. and Avdoshenko، نويسنده , , Stanislav M. and Khavrel، نويسنده , , Pavel A. and Sidorov، نويسنده , , Lev N. and Lebedkin، نويسنده , , Sergey F. and Mazej، نويسنده , , Zoran and ?emva، نويسنده , , Boris and Strauss، نويسنده , , Steven H. and Boltalina، نويسنده , , Olga V.، نويسنده ,
Abstract :
The volatile fluorofullerene products of high-temperature reactions of C60 with the ternary manganese(III, IV) fluorides KMnF4, KMnF5, A2MnF6 (A+ = Li+, K+, Cs+), and K3MnF6 were monitored as a function of reaction temperature, reaction time, and stoichiometric ratio by in situ Knudsen-cell mass spectrometry. When combined with fluorofullerene product ratios from larger-scale (bulk) screening reactions with the same reagents, an optimized set of conditions was found that yielded the greatest amount of C60F8 (KMnF4/C60 mol ratio 28–30, 470 °C, 4–5 h). Two isomers of C60F8 were purified by HPLC, one of which has not been previously reported. Quantum chemical calculations at the DFT level combined with 1D and 2D 19F NMR, FTIR, and FT-Raman spectroscopy indicate that the C60F8 isomer previously reported to be 1,2,3,8,9,12,15,16-C60F8 is actually 1,2,3,6,9,12,15,18-C60F8, making it the first high-temperature fluorofullerene with non-contiguous fluorine atoms. The new isomer, which was found to be 1,2,7,8,9,12,13,14-C60F8, is predicted to be 5.5 kJ mol−1 more stable than 1,2,3,6,9,12,15,18-C60F8 at the DFT level. In addition, new DFT calculations and spectroscopic data indicate that the compound previously isolated from the high-temperature reaction of C60 and K2PtF6 and reported to be 16-CF3-1,2,3,8,9,12,15-C60F7 is actually 18-CF3-1,2,3,6,8,12,15-C60F7.
