Formation of Gas-Phase Formate in Thermal Reactions of Carbon Dioxide with Diatomic Iron Hydride Anions.

The hydrogenation of carbon dioxide involves the activation of the thermodynamically very stable molecule CO2 and formation of a C-H bond. Herein, we report that HCO2 - and CO can be formed in the thermal reaction of CO2 with a diatomic metal hydride species, FeH- . The FeH- anions were produced by laser ablation, and the reaction with CO2 was analyzed by mass spectrometry and quantum-chemical calculations. Gas-phase HCO2 - was observed directly as a product, and its formation was predicted to proceed by facile hydride transfer. The mechanism of CO2 hydrogenation in this gas-phase study parallels similar behavior of a condensed-phase iron catalyst.