Catalysts capable of efficiently interconverting electrical energy and fuels will be important for a flexible and sustainable energy supply in the future. This will require an understanding of the contributions of the first, second, and outer coordination spheres of these catalysts to fundamental hydride and proton transfer steps occurring during the catalytic cycle. This modular approach will be illustrated for the development of [Ni(diphosphine)2]2+ complexes in which the diphosphine ligand contains a pendant base. Thermodynamic models allow the solution bond dissociation free energies of monohydrdie and dihydride complexes to be determined. This thermodynamic information provides an important starting point for the rational design of proton relays incorporated in the second coordination sphere. Energy matching of these proton relays to the thermodynamic properties of the first coordination sphere can provide efficient catalysts for H2 production and oxidation. Insights into the different roles played by the pendant bases during the catalytic cycles will be discussed. The outer coordination sphere also plays an important role in the observed catalytic rates, in proton transfer reactions, and in the design of catalysts suitable for electrode modification.
ASJC Scopus subject areas
- Chemical Engineering(all)