N-Heterocyclic Carbene Ligands Bearing Hydrogen Atom Transfer Moieties: Synthesis and Catalytic Potential
Over the course of evolution, Nature has devised metalloenzymes that convert plentiful solar energy into chemical energy: Photosynthesis produces carbohydrates and dioxygen from carbon dioxide, water and solar energy. Carbohydrates are energy-loaded molecules that can be stored and consummed (to release energy) upon demand. Energy is stored within a molecule in the form of chemical bonds which consists of pairs of electrons between atoms. Redistributing electron-pairs between atoms allows to control the flow of energy. To orchestrate this delicate process, catalysts contribute to canalize the flow of electrons. For this purpose, catalysts temporarily store and release pairs of electrons, thus favouring the reshuffling of bonds and energy.
In a biomimetic spirit, it is proposed to develop catalysts that are capable of storing pairs of electrons both on an organic moiety and a central metal. In this context, catalysts consisting of abundant metals (iron, copper, manganese etc.) will be tested for the oxidation of water or methane to produce dioxygen or methanol.
It is anticipated that this approach will lead to the development of more efficient catalytic systems to produce chemical energy from solar energy, thus contributing to lower the cost and the environmental impact of these artificial photosynthesis catalysts.