Electrochemical, ESR and theoretical studies of [6,6]-opened C60(CF2), cis-2-C60(CF2)2 and their anions

Abstract

Electrochemical behavior of C₆₀(CF₂)_n, n= 1, 2 and C₆₀(CCl₂) has been investigated. [6,6]-Opened C₆₀(CF₂) and cis-2-C₆₀(CF₂)₂ exhibit reversible reductions at potentials 150 and 145 mV more positive than C₆₀, unlike the related [6,6]-closed C₆₀(CCl₂), which shows reduction at the potential close to that for C₆₀. The structures, electron localization and lifetimes of the observed radical anions C₆₀(CF₂)⁻˙ and cis-2-C₆₀(CF₂)₂⁻˙ have been elucidated by the ESR study and DFT calculations. The protonation pathway of decay of C₆₀(CF₂)⁻˙ yields [6,6]-opened 1,9-dihydro-(1a,1a-difluoro-1aH-1(9)a-homo(C₆₀-I_h)fullerene, C₆₀(CF₂)H₂, which becomes the first characterized derivative of [6,6]-opened C₆₀(CF₂). DFT calculations of the structure and electron affinity of a number of homofullerene structures have been carried out to rationalize the experimental findings.