Novel hexabutylsulphonyltribenzotetraazachlorin-fullerene (C60) complexes of iron (FeHBSTBTAC-C60) and cobalt (CoHBSTBTAC-C60) have been synthesized and their electrochemistry and oxygen reduction reaction (ORR) compared with their octabutylsulphonylphthalocyanine analogues (FeOBSPc and CoOBSPc). It is proved that electron-withdrawing substituents (-SO2Bu and C60) on phthalocyanine macrocycle exhibit distinct impact on the solution electrochemistry of these metallophthalocyanine (MPc) complexes. The more electron-withdrawing C60 substituent suppressed ORR compared to the -SO2Bu in alkaline medium. FeOBSPc showed the best ORR activity involving a direct 4-electron mechanism, a rate constant of ∼1 × 108 cm3 mol-1 s-1 and a Tafel slope of -171 mV dec-1.
- Cyclic voltammetry
- Metal (Fe, Co) phthalocyanine-C
- Oxygen reduction
- RDE experiment
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