MIL-100(Fe), a metal−organic framework containing coordinatively unsaturated iron sites, was prepared by a solvothermal method and utilized in cyclohexane oxidation. Interestingly, the composition and fraction of redox-active Fe(II/III) sites in MIL-100(Fe) could be tuned by using different pretreatment temperatures. The obtained materials were characterized by means of field-emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (PXRD), N2 adsorption-desorption isotherms, and X-ray photoelectron spectroscopy (XPS). Due to the presence of redox-active coordinatively unsaturated sites (CUS) at the iron atoms, MIL-100(Fe) exhibited good performance for cyclohexane oxidation under mild reaction conditions. Oxidation rates were significantly enhanced when reduced FeII sites were generated by high-temperature pretreatments. In either high-temperature or low-temperature pretreatment, the isolated Fe(II/III) sites in MIL-100 were far more reactive in cyclohexane oxidation than were bulk iron oxide materials. Finally, possible reaction pathways were proposed based on radical, Haber-Weiss routes.
- Metal−organic frameworks (MOFs)
- Redox-active sites
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry