Nickel(II) Tetraphenylporphyrin as an Efficient Photocatalyst Featuring Visible Light Promoted Dual Redox Activities

Abstract Nickel(II) tetraphenylporphyrin (NiTPP) is presented as a robust, cost‐effective and efficient visible light induced photoredox catalyst. The ground state electrochemical data (CV) and electronic absorption (UV‐Vis) spectra reveal the excited state redox potentials for [NiTPP] * /[NiTPP] .− and NiTPP] .+ /[NiTPP] * couples as +1.17 V and −1.57 V vs SCE respectively. The potential values represent NiTPP as a more potent photocatalyst compare to the well‐explored [Ru(bpy) 3 ] 2+ . The non‐precious photocatalyst exhibits excited state redox reactions in dual fashions, i. e., it is capable of undergoing both oxidative as well as reductive quenching pathways. Such versatility of a photocatalyst based on first‐row transition metals is very scarce. This unique phenomenon allows one to perform diverse types of redox reactions by employing a single catalyst. Two different sets of chemical reactions have been performed to represent the synthetic utility. The catalyst showed superior efficiency in both carbon‐carbon and carbon‐heteroatom bond‐forming reactions. Thus, we believe that NiTPP is a valuable addition to the photocatalyst library and this study will lead to more practical synthetic applications of earth‐abundant‐metal‐based photoredox catalysts. magnified image