Charge effects regulate reversible CO2 reduction catalysisElectronic supplementary information (ESI) available: Synthetic procedures, spectroscopic characterization, and tabulated data. See DOI: 10.1039/c8cc04370a

Modular but geometrically constrained ligands were used to investigate the impact of key ligand design parameters (charge and bite angle) on CO 2 hydrogenation and formic acid dehydrogenation activity. These studies yielded an optimized catalyst that achieved over 118 000 turnovers in CO 2 hydrogenation, 247 000 turnovers in HCO 2 H dehydrogenation, was applied in a hydrogen storage device used for 6 cycles of hydrogen storage/release without requiring changes in pH or solvent, and generated H 2 /CO 2 gas at a pressure of 190 atm from formic acid. Modular but geometrically constrained ligands were used to investigate the impact of key ligand design parameters (charge and bite angle) on CO 2 hydrogenation and formic acid dehydrogenation activity.