Evidences of Electron Transfer of a Fullerene Anion Radical (C60(•-)) Prepared under Visible-Light Illumination at a Nitrobenzene/Water Interface.

Fullerene (C60) changes to its anion radical (C60(•-)) in the presence of tetraphenylborate (TPB(-)) under visible-light illumination. Using voltammetry at a liquid/liquid interface, we investigated the electron transfer (ET) between C60(•-), previously prepared based on this photochemical reaction, in a nitrobenzene (NB) solution and hexacyanoferrate(III) ([Fe(CN)6](3-)) or proton in an aqueous solution. We suggest that positive currents appearing in voltammograms are due to the ion transfer of decomposition products of TPB(-) and ET from C60(•-) in the NB phase to [Fe(CN)6](3-), or proton in the W phase. (11)B NMR revealed that TPB(-) decomposed to some borate anions during the photochemical reaction of fullerene. Furthermore, when the NB solution containing C60(•-) was mixed with an aqueous solution containing [Fe(CN)6](3-) or proton, absorption bands of C60(•-) in a visible/near infrared absorption spectrum disappeared. This disappearance supports the ET across the NB/W interface. This finding is significant as both an example of ET at a liquid/liquid interface including photochemical reactions and the photochemistry of C60.