GAS-PHASE REACTIONS OF THE BUCKMINSTERFULLERENE CATIONS C-60(CENTER-DOT-60(2+), AND C-60(CENTER-DOT-3+) WITH ALDEHYDES, KETONES, CARBOXYLIC-ACIDS, AND ESTERS(,) C)

The reactions of the fullerene ions C-60(.+), C-60(2+), and C-60(.3+) with the carbonyl and carboxyl-containing molecules R-CHO (R = H, CH3, CH2H5), CH3-CO-R (R = CH3, C2H, C2H5, n-C3H7), C2H5-CO-C2H5, c-C5H8O, R-COOH (R = H, CH3), and R-COOCH3 (R = H, CH3), have been studied usi ng a Selected-Ion Flow Tube (SIFT) at 294 +/- 2K and 0.35 +/- 0.01 Tor r of helium. A wide range in reactivity was observed. The monocation C -60(.+) was unreactive with all of the neutrals surveyed. The dication C-60(2+) was observed to add to most of the neutrals: the efficiency of adduct formation was seen to be strongly dependent upon the functio nal group, and was also observed to increase with increasing size of t he alkyl substituents. The adducts of ketones, aldehydes and carboxyli c acids were observed to undergo proton transfer to the reactant neutr al, as a secondary process; in contrast, proton transfer did not occur from the adducts of esters. Structural factors can account for these differences in reactivity. Proton transfer from carbonyl-containing ad ducts is presumed to involve deprotonation from an ct: carbon atom, as indicated by the failure of the dicationic adducts of benzaldehyde to undergo deprotonation. Proton transfer from the carboxylic acid adduc ts involves loss of the carboxyl proton rather than alpha C-H proton l oss, since the ester adducts did not display proton transfer. The reac tion chemistry of C-60(.3+) With these neutrals was dominated by charg e transfer, although addition to some neutrals with an ionization ener gy, IE > 9.9 eV was noted also. General features of the secondary chem istry of the triply-charged adducts were similar to the features of th e dication adduct chemistry: similar structural factors appear to infl uence the dication and trication adduct chemistry, although a greater tendency towards charge separation reactions was apparent in the chemi stry of the tricationic adducts. Notably, a methyl cation transfer cha nnel was observed in the reactions of the tricationic ester adducts wi th the parent neutrals.