The projects outlined herein are primarily aimed at characterizing a new generation of heterogeneous catalysts with novel dynamic nuclear polarization (DNP) solid-state nuclear magnetic resonance (SSNMR) experiments. DNP is an emerging technology which is designed to enhance the signal of NMR experiments. To date, most previous DNP NMR experiments have been restricted to biological systems. Before such DNP SSNMR studies can be applied to characterize single site heterogeneous catalysts it is necessary to develop methods for obtaining efficient DNP enhancement of nuclei which reside on the surface of the support material. We have suggested and previously demonstrated that a novel incipient wetting impregnation approach can be utilized to bring the radicals into close contact with the silica surface. This approach will be refined in order to obtain optimal DNP signal enhancements for the surface sites of the support materials and for molecules which are immobilized on the surface of support materials. With these methods for optimal DNP SSNMR experiments in hand, focus will be given to DNP SSNMR studies of the support materials and a new generation of flexible heterogeneous olefin metathesis catalysts. We will demonstrate that surface enhanced DNP SSNMR experiments are a straightforward and general method for probing the surface sites of a variety of support materials, such as mesoporous silicas and particulate alumina. Novel experiments designed to probe the structure and dynamics of the flexible heterogeneous catalysts will then be undertaken. This is anticipated to result in new state of the art approaches for characterizing inorganic materials and will directly aid in the development of a new generation of olefin metathesis catalysts.
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