Rather than teasing out the existence of such structures from energetically diverse populations on surfaces, we will present preliminary results on our route to the deliberate construction of dimers of catalytic oxides on high surface-area supports. We have synthesized mu-oxo bridged metal dimers stabilized by multidentate amine ligands. Suitable ligand modification creates covalent tethers for grafting to surfaces, but the charge of these complexes also allows for exchange and impregnation techniques. Initial syntheses have focused on known manganese triazacyclononane complexes grafted onto silica and other common oxide supports.
We will present physical characterization (TGA and nitrogen physisorption) and spectroscopic characterization (solid state NMR and UV-visible) to demonstrate that the metal oxide structures synthesized in solution translate into supported oxides of defined structure. It is expected that deliberate synthesis of supported, oligomeric catalytic oxides will lead to improved structure-function relationships and insight into how to target (or avoid) these structures in other catalyst syntheses.