| Abstrakt: |
Oxygen-containing fluoro[60]fullerenes have been isolated from HPLC purification of C60F36 (obtained by fluorination of [60]fullerene with MnF3) and partly characterised by mass, IR, and 19F NMR spectroscopy. They include C60F35OH (1402 amu), arising from nucleophilic substitution of F in C60F36 by OH, and C60F34O (1382 amu) due to subsequent elimination of HF. Both C60F33O·OH (1380 amu) and C60F32O2 (1360 amu), obtained by repetition of these steps, are also formed. The EI mass spectra show the presence of C59F34 (1354 amu), C59F32O (1332 amu) and C58F32 (1304 amu), due to CO loss from the oxide precursors. The corresponding hydroxides and epoxides, derived from the presence of traces of C60F34/38/40, are also observed. The slow conversion of C60F36 to C60F34O in CDCl3, arising from reaction with traces of water in the solvent, was monitored by 19F NMR spectroscopy. On a Cosmosil Buckyprep column, compounds containing more fluorines elute faster than those with correspondingly less, oxides elute slower than the precursor fluorides, and hydroxides elute faster than the corresponding fluorides. The oxides are more soluble in hexane than C60F36, which aids preliminary purification. Some fluorofullerene epoxides show strong IR bands in the carbonyl region but this probably does not reflect alternative ketonic structures (derivable in principle by six-centre eliminations from fluorohydroxyfullerenes) since they would be cage-opened. |
