Efficient and Mild Carbon Dioxide Hydrogenation to Formate Catalyzed by Fe(II) Hydrido Carbonyl Complexes Bearing 2,6-(Diaminopyridyl)diphosphine Pincer Ligands

Abstract

Fe(II) hydrido carbonyl complexes supported by PNP pincer ligands based on the 2,6-diaminopyridine scaffold were found to promote the catalytic hydrogenation of CO2 and NaHCO3 to formate in protic solvents in the presence of bases, reaching quantitative yields and high TONs under mild reaction conditions, with pressures as low as 8.5 bar and temperatures as low as 25 °C. NMR and DFT studies highlighted the role of dihydrido and hydrido formate complexes in catalysis.