Computational design of a renewable organic reagent for photochemical reduction of CO2 with visible light

Density functional calculations have been used to design an organic molecule that should be capable of reducing carbon dioxide to formic acid, using the energy from visible light. The compound combines the functions of photocatalyst and reducing agent, and is designed to be renewable by hydrogenation of its oxidation product. The keys to the design are the photochemical generation of a zwitterion in a form that is kinetically inhibited from return to the ground state, and the reduction of CO2 by direct hydride addition rather than separate electron and proton additions.