Reactions of C-60(center dot+), C-60(2+) and C-60(center dot 3+) with C2H2 and C2H4 in the gas phase: Polymerization initiated by C-60(center dot 3+).

Reactions of the C-60 cations C-60(.+), C-60(2+) and C-60(.3+) have been investigated with C2H2 and C2H4 in the gas phase using the Selected-Ion Flow Tube (SIFT) technique at 295+/-2 K and 0.35+/-0.02 Torr of helium. Although C-60(.+) was found to be unreactive (k < 1x10(-12) cm(3) molecule(-1) s(-1)), and C-60(2+) reacted only slowly (k less than or equal to 2x10(-12) cm(3) molecule(-1) s(-1)) by adduct formation, C-60(.3+) reacted rapidly with C2H2 by adduct formation (k = 6.6x10(-11) cm(3) molecule(-1) s(-1)) and with C2H4 by adduct formation (30%) and electron transfer (70%) (k = 1.7x10(-9) cm(3) molecule(-1) s(-1)). C-58(.3+), which was present as an impurity ion, was observed to react 10 times faster than C-60(.3+) with C2H2, k = 6.0x10(-10) cm(3) molecule(-1) s(-1) and this was attributed to a greater sp(3) character of the reacting C site. Higher-order addition reactions were observed with C-60(.3+) and these were interpreted as the first example of cation-induced ''ball-and-chain'' and C-58(.3+) polymerization by triply-charged fullerene cations. Mechanisms have been proposed for this polymerization without and with an intramolecular hydride shift in the derivatized fullerene cation. Also, C60C2H4.3+ was observed to undergo proton transfer with C2H4 and this is the first example of such a reaction with a triply-charged C-60 derivative. (C) 1996 Elsevier Science Ltd