Saturation versus inductive effects: the electrochemistry of the C70Ph2n (n = 1–5) series

Abstract

Several arylfullerenes, C₇₀Ph_2n (n = 1–5), are characterised. Their electrochemical properties, investigated by cyclic voltammetry, are the result of a competition between the electron-withdrawing effect exerted by the phenyl groups and the destabilization of redox orbitals deriving from the saturation of double bonds. C₇₀Ph₂ is easier to reduce than C₇₀, a feature possibly shared with C₇₀Ph₄ that makes these derivatives of C₇₀ amongst the best electron acceptor molecules so far discovered. In the following derivatives, destabilization prevails, and reductions become increasingly more cathodic along the series. NMR spectroscopy is used to investigate C₇₀Ph_2n (n = 1–3). Finally, calculation of the LUMO energies supports the earlier reduction of C₇₀Ph₂ and calculations also indicate the layering of the injected charges, in the multiply-reduced species, over concentric shells.

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