Partial substitution of ZnII by MnII in Zn4O(terephthalate)3 (MOF-5) leads to a distorted all-oxygen ligand field supporting a single MnII site, whose structure was confirmed by Mn K-edge X-ray absorption spectroscopy. The MnII ion at the MOF-5 node engages in redox chemistry with a variety of oxidants. With tBuSO2PhIO, it produces a putative MnIV-oxo intermediate, which upon further reaction with adventitious hydrogen is trapped as a MnIII-OH species. Most intriguingly, the intermediacy of the high-spin MnIV-oxo species is likely responsible for catalytic activity of the MnII-MOF-5 pre-catalyst, which in the presence tBuSO2PhIO catalyzes oxygen atom transfer reactivity to form epoxides from cyclic alkenes with &gt;99% selectivity. These results demonstrate that MOF secondary building units serve as competent platforms for accessing terminal high-valent metal-oxo species that consequently engage in catalytic oxygen atom transfer chemistry owing to the relatively weak ligand fields provided by the SBU.

Selective catalytic olefin epoxidation with MnII-exchanged MOF-5

255th National Meeting (2018)

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