Efficient Synthesis of Porphyrin–Iridium Complex for Enhanced Cocatalyst‐Free Photocatalytic Hydrogen Evolution

Abstract A new porphyrin–iridium complex, T‐Ir‐ZnPF, is synthesized facilely through a one‐pot, nucleophilic substitution reaction between the iridium (Ir) complex Ir‐NH 2 and zinc(II)‐tetrakis(pentafluorophenyl)porphyrin ZnPF. In this porphyrin, the Ir‐motif acts as a triplet energy donor, while the porphyrin moiety serves as a singlet energy acceptor. An efficient Förster resonance energy transfer from the Ir‐motif to the porphyrin moiety enables exceptional light‐harvesting capabilities in the broad ultraviolet–visible region, a longer photoexcited state electron lifetime, and a higher photoluminescent quantum yield for T‐Ir‐ZnPF compared to ZnPF without the Ir‐motif. Moreover, T‐Ir‐ZnPF exhibits inhibition of aggregation‐caused quenching, resulting in suppressed nonradiative decay channels and consequently long‐lived photoexcited states. The cocatalyst‐free homogeneous photocatalytic hydrogen evolution (PHE) system of T‐Ir‐ZnPF produces a PHE rate ( η H 2 ) of 5.34 mmol g⁻¹ h⁻¹. Under the same photocatalytic conditions, ZnPF did not produce hydrogen, while Ir‐NH 2 delivered a very low η H 2 of 0.20 mmol g⁻¹ h⁻¹. Since the Stern–Volmer quenching constant of T‐Ir‐ZnPF is higher than those of ZnPF and Ir‐NH 2 , the photoexcited reduced T‐Ir‐ZnPF species are formed more readily by gaining electrons from triethylamine. Subsequently, a direct and fast electron transfer from the reduced T‐Ir‐ZnPF to protons leads to a high cocatalyst‐free PHE.