Isolation and Studies of Oxoheme Complexes in Metal-Organic Frameworks

The proposed work seeks to test the hypotheses that metal-organic frameworks (MOFs) can be employed to isolate oxoheme species, which can then be used to carry out oxygen-transfer chemistry to organic substrates. Embedding heme centers within the porous structure of a MOF will forestall unwanted reaction pathways, such as bimolecular condensation, often associated with molecular chemistry. The geometric and electronic structures of the oxo- and related oxyheme species will be thoroughly proved using a suite of techniques, including X-ray diffraction, Mössbauer spectroscopy, SQUID magnetometry, EPR spectroscopy, X-ray absorption spectroscopy, and nuclear resonance vibrational spectroscopy (with collaborators at Argonne National Laboratory). Of particular interest will be the effects of axial ligation to the overall complex structure. The stoichiometric and catalytic reactivity of the oxoheme complexes with C-H bonds and olefins, as a function of axial ligand substitution, will be investigated in order to uncover fundamental structure-function relationships. Included within this proposal is an outline our recent preliminary results involving isolation of oxyheme complexes in MOFs, which demonstrate the potential likelihood for success of the proposed research. Overall, the proposed work will contribute significantly to our understanding of catalytic intermediates involved in alkane oxidation and help to inform the design of future catalysts.