A phosphine-free molecularly-defined Ni( ii ) complex in catalytic hydrogenation of CO 2

The first non-phosphine Ni complex with “carbazolato-bis-NHC” pincer ligand is developed for efficient catalytic hydrogenation of CO 2 to formate, offering TON up to 5476 and yield up to 92% for the formate product from a reaction on ∼27 mmol scale.