Catalytic methods for the synthesis of main group molecules

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Our research program works to address issues of sustainability in the synthesis of important molecules and materials based on inorganic elements such as silicon and phosphorus, through the design and study of atom economic catalysis.Catalysis is the ultimate tool in developing sustainable manufacturing processes, since it reduces the energy required to make new molecules and materials, and can direct chemical reactions to give a single, desirable product when non-catalytic methods give mixtures that must then be separated in energy-intensive ways. Waste is even further reduced through the coupling of catalysis with the strategy of “atom economy”, choosing reactions where as much as possible of each reagent molecule is incorporated into the desired product.Traditional routes to important silicon- and phosphorus-containing materials (e.g. Si-based plastics with useful optical and electronic properties, P-centered molecules needed by the pharmaceutical industry to green up their processes) rely on non-catalytic reactions that generate huge amounts of waste, mostly in the form of eliminated halide salts (e.g. NaCl). This results from using reagents containing element-halogen bonds (e.g. P-Cl), so we are looking at alternative reactions of reagents containing element-hydrogen bonds (e.g. P-H). Our reactions generate either no byproducts or very small, light ones like H2(g). In some cases, these reactions won't happen at all without catalysts, while in other cases the catalysts help the reactions occur faster. We strive to ensure these reactions are efficient (fast, low energy), general (work for many different classes of reagent molecules), and selective (lead to the single most desirable product). This proposal draws on my long experience in the catalytic reactions of Si-H bonds to focus on the far less-developed area of catalytic P-H bond activation, in which we have become active participants. The “phosphine” molecules we're making are important reagents in their own right, e.g. in the synthesis of fire retardants, agrochemicals, and especially fine chemicals like pharmaceuticals and fragrances. We will concentrate on deciphering the intimate details of how the catalysts we design interact with reagents containing P-H bonds to allow the new phosphine molecules to form. We can then use this mechanistic information to modify our catalysts, tuning them for optimal performance. Existing catalysts activate the P-H bond by removing the hydrogen as H+ (proton). We'll work on improving these catalysts to make them more efficient and selective for single products. We are even more excited, though, by the prospect of exploring entirely new catalytic processes that rely on removing the hydrogen as either H (hydride) or H (hydrogen atom). The success of these new ventures will represent a paradigm shift in the catalytic chemistry of phosphorus.