Site-Selective Supramolecular Complexation Activates Catalytic Ethane Oxidation by a Nitrido-Bridged Iron Porphyrinoid Dimer |
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Authors: | Dr Nozomi Mihara Dr Yasuyuki Yamada Dr Hikaru Takaya Prof Yasutaka Kitagawa Dr Kazunobu Igawa Prof Katsuhiko Tomooka Prof Hiroshi Fujii Prof Kentaro Tanaka |
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Institution: | 1. Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602 Japan;2. IRCELS, Institute for Chemical Research, Kyoto University, Goka-sho Uji, Kyoto, 611-0011 Japan;3. Division of Chemical Engineering, Department of Materials Engineering, Science, Graduate School of Engineering Science, Osaka University, 1–3 Machikaneyama-cho, Toyonaka, Osaka, 560-8531 Japan;4. Institute for Materials Chemistry and Engineering, and IRCCS, Kyushu University, Kasuga-Koen, Kasuga, Fukuoka, 816-8580 Japan;5. Department of Chemistry, Graduate School of Humanities and Science, Nara Women's University, Kitauoyanishi, Nara, 630-8506 Japan |
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Abstract: | Development of supramolecular methods to further activate a highly reactive intermediate is a fascinating strategy to create novel potent catalysts for activation of inert chemicals. Herein, a supramolecular approach to enhance the oxidizing ability of a high-valent oxo species of a nitrido-bridged iron porphyrinoid dimer that is a known potent molecular catalyst for light alkane oxidation is reported. For this purpose, a nitrido-bridged dinuclear iron complex of porphyrin-phthalocyanine heterodimer 3 5+, which is connected through a fourfold rotaxane, was prepared. Heterodimer 3 5+ catalyzed ethane oxidation in the presence of H2O2 at a relatively low temperature. The site-selective complexation of 3 5+ with an additional anionic porphyrin (TPPS4?) through π–π stacking and electrostatic interactions afforded a stable 1:1 complex. It was demonstrated that the supramolecular post-synthetic modification of 3 5+ enhances its catalytic activity efficiently. Moreover, supramolecular conjugates achieved higher catalytic ethane oxidation activity than nitrido-bridged iron phthalocyanine dimer, which is the most potent iron-oxo-based molecular catalyst for light-alkane oxidation reported so far. Electrochemical measurements proved that the electronic perturbation from TPPS4? to 3 5+ enhanced the catalytic activity. |
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Keywords: | iron oxidation phthalocyanines porphyrinoids supramolecular chemistry |
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