<br/>Typical cross-coupling reactions in both research and industrial processes tend to focus on homogeneous methodologies. These processes, however, can create difficult post reaction separations and present a problem in catalyst recyclability. A more desirable approach for the development of these catalytic experiments is the application of non-noble catalysts into a heterogeneous system capable of carrying out cross-coupling reactions in an easy to separate and recyclable manner. To this end, we have developed a system using a single site molecular nickel catalyst on a silica support to undergo Suzuki coupling in aqueous solvents. The nickel catalyst is ineffective in a homogeneous aqueous solution. However, when heterogenized via surface attachment of the catalyst onto a silica oxide support, a 25% cross-coupled product yield can be obtained. To further increase stability of the catalyst, Atomic Layer Deposition (ALD) was used to immobilize the catalyst to the oxide support. Addition of a TiO<sub>2</sub> layer with ALD remarkably increased the product yields to greater than 90%. The ALD stabilized single site molecular catalyst is capable of successfully carrying out Suzuki coupling in high yields across a wide range of substrates in a manner previously unseen for heterogeneous systems. Furthermore, these ALD stabilized single site molecular catalysts show bifunctional capabilities of which lower concentrations of base is necessary for reactivity. This presentation outlines this new methodology of catalyst synthesis, the effects of ALD on stability and reactivity, and the extent of Suzuki coupling exhibited, alone with outlining future work to explore the bifunctionality of the catalyst.

Immobilization of molecular nickel cross-coupling catalyst on oxide supports via atomic layer deposition

255th National Meeting (2018)

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