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

Fullerene (C-60) changes to its anion radical (C-60(center dot-)) in the presence of tetraphenylborate (TPB-) under visible-light illumination. Using voltammetry at a liquid/liquid interface, we investigated the electron transfer (ET) between C-60(center dot-), 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 Cur in the NB phase to [Fe(CN)(6)](3-), or proton in the W phase. B-11 NMR revealed that TPB- decomposed to some borate anions during the photochemical reaction of fullerene. Furthermore, when the NB solution containing C-60(center dot-) was mixed with an aqueous solution containing [Fe(CN)(6)](3-) or proton, absorption bands of C-60(center dot-) 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 C-60.