An enzyme-mimic single Fe-N(3) atom catalyst for the oxidative synthesis of nitriles via C─C bond cleavage strategy

The cleavage and functionalization of recalcitrant carbon─carbon bonds is highly challenging but represents a very powerful tool for value-added transformation of feedstock chemicals. Here, an enzyme-mimic iron single-atom catalyst (SAC) bearing iron (III) nitride (FeN(3)) motifs was prepared and found to be robust for cleavage and cyanation of carbon–carbon bonds in secondary alcohols and ketones. High nitrile yields are obtained with a wide variety of functional groups. The prepared FeN(3)-SAC exhibits high enzyme-like activity and is capable of generating a dioxygen-to-superoxide radical at room temperature, while the commonly reported FeN(4)-SAC bearing FeN(4) motifs was inactive. Density functional theory (DFT) calculation reveals that the activation energy of dioxygen activation and the activation energy of the rate-determining step of nitrile formation are lower over FeN(3)-SAC than FeN(4)-SAC. In addition, DFT calculation also explains the catalyst’s high selectivity for nitriles.