Isolation of C60(CF3)n (n = 2, 4, 6, 8, 10) with high compositional purity

The high temperature reaction of C60 with silver(I) trifluoroacetate followed by 500 °C sublimation and subsequent HPLC purification has led to the isolation of the five trifluoromethyl[60]fullerenes C60(CF3)n (n=2, 4, 6, 8, 10). Four of them have >90% compositional purity. Two of the compounds, C60(CF3)4 and C60(CF3)6, were obtained as C1-symmetry isomers with >90% isomeric purity, and a sample of C60(CF3)2 also contained ca. 15–20% of a Cs-symmetry isomer of C60(CF3)4. The new compounds were characterized by IR and EI mass spectrometry (all five compounds), 19F NMR spectroscopy (C60(CF3)2, C60(CF3)4, and C60(CF3)6), and 2D COSY 19F NMR spectroscopy (C60(CF3)4 and C60(CF3)6). Calculations at the AM1 and DFT levels of theory have led to the prediction of the most likely structures for C60(CF3)2, C1-C60(CF3)4, Cs-C60(CF3)4, and the two most likely structures of C1-C60(CF3)6.