Oxygen Reduction to Water by a Cofacial Dimer of Iron(III)–Porphyrin and Iron(III)–Phthalocyanine Linked through a Highly Flexible Fourfold Rotaxane

5 years ago

Oxygen Reduction to Water by a Cofacial Dimer of Iron(III)–Porphyrin and Iron(III)–Phthalocyanine Linked through a Highly Flexible Fourfold Rotaxane

Yasuyuki Yamada, Kentaro Tanaka, Shin Aoyama, Katsuhiko Tomooka, Kazunobu Igawa, Nozomi Mihara, Hikaru Takaya, Yasutaka Kitagawa

A μ-oxo-dinuclear iron complex of a supramolecular porphyrin–phthalocyanine conjugate was synthesized and its catalytic electrochemical oxygen reduction properties were investigated. In the conjugate, porphyrin and phthalocyanine units were connected to form a cofacial dimeric structure through a flexible fourfold rotaxane linkage, which was advantageous for accommodating small substrates between the iron centers. The conjugate showed efficient catalytic properties, at more positive potentials than those of other reported dinuclear porphyrinoid iron complexes, to selectively afford water through a four-electron reduction process. Structurally adaptable catalyst: A cofacial dimer of an iron porphyrin and an iron phthalocyanine, connected through a highly flexible fourfold rotaxane linkage, was prepared as a catalyst for electrochemical O2 reduction (see scheme). The dinuclear iron complex catalyzes the four-electron reduction of O2 to water selectively at a lower overpotential than those of other dinuclear iron complexes of porphyrinoids.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201700082