Transition Metal/Aluminium Bimetallics for Cooperative Catalysis

点击翻译按钮获取中文摘要

Catalysis - the enhancement of the rate and selectivity of a chemical transformation through the intervention of a compound that is regenerated at the end of reaction (and can therefore be repeatedly recycled), represents an immensely powerful tool for assembling complex molecules in a resource-efficient manner. As such, catalysis is central to chemical manufacturing, with over 75% of chemical products requiring the use of a catalyst at some stage in their manufacture. The annual world-wide market for products derived from catalytic processes is in excess of $9 trillion, and catalysts are widely employed in key industrial processes allied to the manufacture of commodity and fine chemicals, food products, pharmaceuticals, fuels, polymers, etc. Moreover, the realization of new catalysts and catalytic processes is critical to developing future production capabilities within a sustainable framework, which reduces waste and makes optimal use of chemical feedstocks. Bonds between carbon and hydrogen are ubiquitous in naturally occurring chemical compounds. Direct functionalization of C-H bonds (i.e. converting them into more useful chemical building blocks) represents an attractive, atom-efficient approach to construct valuable chemical targets. However, this approach brings a number of chemical challenges - relating to the facts that C-H bonds are relatively inert (difficult to break), and chemically uniform (so difficult to break selectively). Control of reactivity is therefore difficult to achieve. Drawing inspiration from enzymes (biological catalysts), a number of these issues can be addressed by exploiting bimetallic compounds (i.e. compounds containing two metals) - in which two different metals are tailored to accomplish different chemical tasks. The crux of this proposal is to offer a route for the synthesis and optimization of bimetallic catalysts in which one of the metals is aluminium - an element with a long history of exploitation in catalysis. The development of this approach has been hampered to date by the lack of viable routes to make such catalysts. However, exploiting our recent work, we have the unique opportunity to generate a range of aluminium-containing bimetallics that can be systematically tuned to optimize reactivity characteristics. In doing so, we will establish not only the fundamental chemical reactivity profiles of such systems, but also their capabilities in novel catalytic C-H functionalization processes.