C 1 C60F16O: A Fluorofullerene Ether Having Exceptionally Long Chromatographic Retention

Abstract

From the product of fluorination of [60]fullerene with K2PtF6 at 470 °C, we have isolated a small quantity (ca. 0.5 mg) of C60F16O, an oxahomofluorofullerene (ether) of exceptionally long HPLC retention time (50% greater than any other known fluorofullerene). The 19F NMR spectrum consists of 16 main lines and 8 minor ones, due to C60F16O (a single isomer of C 1 symmetry) and C60F16, respectively. The presence of the latter (absent on initial isolation) indicates this ether to be relatively unstable, confirmed by the failure to obtain an EI mass spectrum. The empirical formula was therefore determined by MALDI‐TOF mass spectrometry in the negative‐ion mode, the laser fluence being carefully adjusted at the threshold of ion formation, whence the only observable signal corresponded to the molecular ion of C60F16O. At slightly higher laser fluence, the base peak of C60F16O·− is accompanied by C60F16 ·− and C60F15O·−. Two closely similar structures (of similar calculated stabilities) are fully consistent with the NMR data. Calculated dipole moments and the exceptionally long retention HPLC retention times suggest that both C60F16 and C60F16O may be dimers.