An enzyme-mimic single Fe-N₃ 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 (FeN₃) 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 FeN₃-SAC exhibits high enzyme-like activity and is capable of generating a dioxygen-to-superoxide radical at room temperature, while the commonly reported FeN₄-SAC bearing FeN₄ 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 FeN₃-SAC than FeN₄-SAC. In addition, DFT calculation also explains the catalyst's high selectivity for nitriles.