Electrocatalytic oxidation and production of hydrogen using cobalt and nickel complexes containing diphospine ligands with pendant nitrogen bases

Catalysts capable of efficient interconversion of electrical energy and fuels will be important for a flexible and sustainable energy supply in the future. Such catalysts require careful design of both the first and second coordination spheres to achieve high activities. In previous work we have reported that nickel complexes containing diphosphine ligands with pendant nitrogen bases can be efficient catalysts for hydrogen oxidation and production. Current studies are focusing on the precise role of the pendant base in these catalytic processes. For nickel complexes it is found that two precisely positioned pendant bases are required for optimal catalyst performance. In contrast for cobalt complexes, optimal catalytic performance is achieved with only one pendant nitrogen base, and precise positioning of the base does not appear to be required.