GAS-PHASE REACTIONS OF SINGLY AND MULTIPLY-CHARGED FULLERENE CATIONS,C-60(X-3), WITH IRON PENTACARBONYL - KINETIC CONTROL BY COULOMBIC BARRIERS() (X=1)

Selected-ion flow tube measurements of rate coefficients and product d istributions 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, C60Fe(CO)(4)(+), bu t the chemistry switches for the higher charge states to charge separa tion by dissociative-electron transfer leading to the elimination of o ne 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 f avourable entropy changes and kinetic control by energy barriers arisi ng from Coulombic repulsion between product ions. (C) 1997 Elsevier Sc ience B.V.