Relationship between the Electron Affinities and Half-Wave Reduction Potentials of Fullerenes, Aromatic Hydrocarbons, and Metal Complexes

Differences in energy for neutral molecule and negative ions upon going from the gas phase to solution. - {delta}{delta}G{sub sol}, have been calculated from gas phase electron affinites and half-wave reduction potentials for a series of fullerenes, aromatic hydrocarbons, metalloporphyrins, and metal complexes in dimethylformamide (DMF). For those compounds with similar charge delocalization, the value of -{delta}{delta}G{sub sol} is constant and equal to 1.76 {+-} 0.06 eV for the fullerenes, 1.99 {+-} 0.05 eV for the aromatic hydrocarbons and the metalloporphyrins, and 2.19 {+-} 0.14 eV for the metal acetylacetonates. The fullerenes form a new class of molecules in which the charge is highly delocalized, and this is demonstrated by the relatively low value of -{Delta}{Delta}{sub sol}. A procedure for determining adiabatic electron affinities from reduction potentials, and vice versa, is established. This procedure is applied to benzene to give an electron affinity of {minus}0.7 {+-} 0.14 eV, to La @ C{sub 82} to give an electron affinity of 3.21 {+-} 0.06 eV, and to Y @ C{sub 82} to give an electron affinity of 3.32 {+-} 0.06 eV. On the other hand, a value of E{sub 1/2} = 0.09 {+-} 0.14 V vs SCE is predicted for the reductionmore » of Ca@C{sub 60} in DMF based upon a reported electron affinity of 3.0 {+-} 0.1 eV. 36 refs., 4 figs., 3 tabs.« less