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

Several arylfullerenes, C70Ph2n (n=1-5), are characterised. Their electroch emical properties, investigated by cyclic voltammetry, are the result of a competition between the electron-withdrawing effect exerted by the phenyl g roups and the destabilization of redox orbitals deriving from the saturatio n of double bonds. C70Ph2 is easier to reduce than C-70, a feature possibly shared with C70Ph4 that makes these derivatives of C-70 amongst the best e lectron 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 C70Ph2n (n=1-3). Finally, calculation of the LUMO energies supports the earlier reduction o f C70Ph2 and calculations also indicate the layering of the injected charge s, in the multiply-reduced species, over concentric shells.