Oxygen reduction with tetrathiafulvalene at liquid/liquid interfaces catalyzed by 5,10,15,20-tetraphenylporphyrin

In this work we report the catalytic effect of 5,10,15,20-tetraphenylporphyrin (H 2 TPP) on the reduction of oxygen (O 2 ) by a weak electron donor, namely tetrathiafulvalene (TTF), at the polarized water/1,2-dichloroethane (DCE) interface. TTF alone, as reported previously, can reduce O 2 slowly via a four-electron transfer pathway to produce water. Herein we show that H 2 TPP can catalyze the reduction of O 2 by TTF to form hydrogen peroxide (H 2 O 2 ) at the water/DCE interface, which was investigated by voltammetry and biphasic shake-flask experiments. The overall process was found to be essentially a proton-coupled electron transfer reaction. And the results also proved that the catalytic activity of H 2 TPP toward O 2 reduction under acid condition arises from the polarization activation of O 2 by H 2 TPP diacid, namely H 4 TPP 2+ .