From Organic to Inorganic Chemistry: Exploiting the Isolobal Analogy to Develop Main Group Catalysts

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Modern society is highly reliant on organic materials for example in technological devices such as smartphone displays, or for drugs to tackle chronic illnesses. However, while the UK and western society seeks to improve the standard of living, the developing world also strives to improve technology and healthcare in their own countries. With a growing population and necessity to improve the quality of life globally there will be ever-increasing demands for the world's resources. This, combined with increased energy prices, could potentially lead to a deterioration in our current standard of living unless new energy and cost efficient processes are identified to meet the expanding global demand. Catalysis plays a pivotal role in maintaining the quality of everyday life worldwide as over 85% of chemical products are generated through catalytic methods. Through lowering the energy barrier of chemical processes, catalysts can direct a reaction's outcome both reducing energy consumption and making chemical processes more efficient. Therefore, the development of new catalysts and improvement of catalytic performance can have a direct influence on numerous major societal issues. Transition metals have dominated these processes owing to their rich reaction chemistry and high activity. However, many of the most active catalysts are typically composed of the so called "precious" metals which are, as their name suggests, expensive owing to their scarcity. While these catalysts are often highly efficient, one major pitfall includes their inherent toxicity. This is particularly significant for consumer products that are taken into the body (e.g. food products or pharmaceuticals) in which regulatory controls requires concentrations of toxic metals to parts per billion levels through meticulous post-reaction catalyst removal. One question which Dr Melen's research aims to answer is: could metal catalysts be circumvented altogether? Over the last 40 years the isolobal analogy (for which Hoffmann was awarded the Nobel Prize in Chemistry) has provided a theoretical foundation for rapid experimental developments in inorganic chemistry. The proposed work will apply the isolobal analogy to generate novel ambiphilic catalysts through the application of synthetic organic chemistry to main group systems. The compounds generated will then be tested in metal-free catalytic hydrogenation, carbon dioxide sequestration and C-H activation/borylation reactions. These are among some of the most important and topical areas of catalysis. For example, with a diverse range of commercial processes, the addition of molecular hydrogen to unsaturated substrates is unparalleled in the chemical industry. Equally, the direct utilisation of carbon dioxide as a C-1 feedstock has been identified by many nations as an area in need of exploration and development. While carbon dioxide is the primary carbon source for life on our planet, it is simultaneously the most significant greenhouse gas and approaches to sequester CO2 are becoming increasingly important. These processes will provide new methods for making fuels and useful compounds in a sustainable manner. Main group, or metal-free, catalysis has become a burgeoning field of which Dr Melen has been a key player. However, this flourishing field is still in its naissance, with many challenges to be overcome before practical applications can be developed. The work described herein will move main group catalysis towards industrial exploitation by applying well-established methodologies in organic chemistry to inorganic main group chemistry and subsequently industry (e.g. the pharmaceuticals sector). This unique opportunity for Dr Melen will allow her to build a team of highly skilled researchers which is of vital importance to her as an emerging leading academic.