Gas-phase reactions of singly and multiply-charged fullerene cations, C60x+ (x = 1–3), with iron pentacarbonyl: kinetic control by Coulombic barriers

摘要

Selected-ion flow tube measurements of rate coefficients and product distributions are reported for the reactions of C60?+, C602+ and C60-3+ with iron pentacarbonyl in helium buffer gas at 0.35 ± 0.01 torr and 294 ± 3 K. A fast bimolecular reaction is observed with C60-+ leading to a stable derivatized C60 cation, C60Fe(CO)4-+, but the chemistry switches for the higher charge states to charge separation by dissociative-electron transfer leading to the elimination of one and two molecules of CO with C602+ and C60?3+, respectively. The specificity of these CO eliminations is rationalized in terms of favourable entropy changes and kinetic control by energy barriers arising from Coulombic repulsion between product ions.