Functional Polymers

Challenge

Prof. Shaver’s research career began in fundamental inorganic chemistry in project far away from sustainability that ranged from catalytic hydroboration to metal-metal double bonds. Still to this day the research team maintains these essential, and fundamental, core chemistry skills. A key target is the replacement of transition metal catalysts – and the environmental, economic and social burden of their mining – with catalysts built from main group elements.

Solution

Metal-free organocatalysts have emerged as alternatives to transition metal catalysts. Composed of more abundant elements, they can be a more sustainable and less toxic option for synthesis. However, their complexity and laborious synthesis can sometimes have a higher footprint than metals themselves.

Our team has been developing recyclable catalysts, such as polymeric frustrated Lewis pairs, poly(FLP)s that combine Lewis bases (phosphines, amines, NHCs) and acids (boranes) with unique reactivity towards small molecules (H₂, CO₂, CO). Reactivity arises from the unquenched Lewis acid and base centres present, bearing bulky groups that prevent them from forming an adduct and thus spark chemical transformations. Building these unique catalysts into polymeric frameworks allow for the catalysts to be readily recycled just by filtration, dramatically improving sustainability. Applying these catalysts to CO₂ and CO transformations and extending reactivity to polymeric frustrated radical pairs is extending the innovation in this work.

Beyond poly(FLP)s we are developing polymeric versions of other organocatalysts and toolboxes to assess the comparative environmental impacts of catalyst choice and efficiency on reaction sustainability.

Impact

Exploring fundamental polymer chemistry challenges is important as it retains our unique skill set in reactive main group chemistry and polymer science. While far away from the commercial relevance of some of our other projects, the unique insights in reactivity, reuse and sustainability assessment ensures that we are future proofing our fundamental science from the start.