The propsed research will involve applying supramolecular principles to different areas of synthetic chemistry. Low valent metal complexes have shown novel reactivity, but one challenge in their preparation is the need for bulky ligands that dramatically decrease their available coordination sphere. This can be circumvented by embedding necessary coordinating ligands in self-assembled cages and frameworks to prevent multiple ligands binding to each metal. This will provide access to low valent complexes which are kinetically stablized, while retaining multiple open coordination sites for binding of additional reactants or bulky substrates. In addition, these systems will allow the use of well-defined low valent catalysts heterogenously. A second strategy will involve tethering two separate metals into close proximity. The different reactivities will be exploited to allow one metal to undergo C-H activation while another activates a small molecule such as carbon dioxide or ammonia. By coupling these two organometallic intermediates the goal will be to directly carboxylate or aminate terminal alkanes. In addition to allow functionalization of more complex molecules, this may provide improved access to nylon precursors. The final strategy will be to tether a highly reactive metal catalyst with a hydrogen bonding moiety. The goal will be to perform reactions at low temperatures to allow the hydrogen bonding motif to direct site-selective C-H functionalization to a pre-determined position from a compatible, hydrogen bond accepting functional group while lower the rate of reaction at intrinsically more reactive secondary and tertiary positions. By changing the size of a tunable linker, it should be possible to prepare a set of catalysts which can functionalize specific positions relative to ketones, amides, and other hydrogen bond-accepting groups, thereby improving the synthetic toolbox for C-H functionalization of carbonyl compounds.

Supramolecular approaches for improving reactivity and selectivity in transition metal catalyzed transformations

250th National Meeting (2015)

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