Gas-phase reactions of singly and multiply-charged fullerene cations, C 60x+ ( x = 1–3), with iron pentacarbonyl: kinetic control by Coulombic barriers

Abstract

Selected-ion flow tube measurements of rate coefficients and product distributions are reported for the reactions of C 60 •+, C 60 2+ and C 60 •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 C 60 •+ leading to a stable derivatized C 60 cation, C 60Fe(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 C 60 2+ and C 60 •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.