Catalytic CH4 oxidation using a μ-nitrido-bridged iron porphyrinoid dimer was successfully activated by supramolecular complexation.

Rigorous process simulation helps in the qualification of direct CO2 to DMC conversion co-assisted by a catalyst and dehydration agent in GHG emission reduction.

Supermolecules such as rotaxanes and catenanes have recently attracted considerable attention due to their potential widespread applications in areas such as molecular machines and switches. Moreover, the development of polyrotaxanes and polycatenanes, comprising multiple cyclic compounds, has allowed the fabrication of structures with novel properties. Although rotaxanes and polyrotaxanes have been extensively prepared from cyclodextrins as building blocks, very few studies have considered the syntheses of cyclodextrin-based polycatenanes. Here we report the one-pot syntheses and isolation of cyclodextrin-based radial polycatenanes with large numbers of cyclic components (>10) attached to a poly(ethylene glycol)–poly(propylene glycol)–poly(ethylene glycol) copolymer core, with characterization performed using Raman spectroscopy, gel permeation chromatography, 1H-NMR spectroscopy, and other techniques. Overall, the results presented herein may be used to develop advanced supramolecular structures and materials, such as molecular machines, molecular actuators, molecular switches, biomaterials, and drug carriers.

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Numerous biomimetic molecular catalysts inspired by methane monooxygenases (MMOs) that utilize iron or copper-oxo species as key intermediates have been developed. However, the catalytic methane oxidation activities of biomimetic molecule-based catalysts are still much lower than those of MMOs. Herein, we report that the close stacking of a μ-nitrido-bridged iron phthalocyanine dimer onto a graphite surface is effective in achieving high catalytic methane oxidation activity. The activity is almost 50 times higher than that of other potent molecule-based methane oxidation catalysts and comparable to those of certain MMOs, in an aqueous solution containing H2O2. It was demonstrated that the graphite-supported μ-nitrido-bridged iron phthalocyanine dimer oxidized methane, even at room temperature. Electrochemical investigation and density functional theory calculations suggested that the stacking of the catalyst onto graphite induced partial charge transfer from the reactive oxo species of the μ-nitrido-bridged iron phthalocyanine dimer and significantly lowered the singly occupied molecular orbital level, thereby facilitating electron transfer from methane to the catalyst in the proton-coupled electron-transfer process. The cofacially stacked structure is advantageous for stable adhesion of the catalyst molecule on the graphite surface in the oxidative reaction condition and for preventing decreases in the oxo-basicity and generation rate of the terminal iron-oxo species. We also demonstrated that the graphite-supported catalyst exhibited appreciably enhanced activity under photoirradiation owing to the photothermal effect.