Nonprecious-Metal-Assisted Photochemical Hydrogen Production from <i>ortho</i>-Phenylenediamine

Abstract

The combination of <i>o</i>-phenylenediamine (opda), which possesses two proton- and electron-pooling capability, with Fe­(II) leads to the photochemical hydrogen-evolution reaction (HER) in THF at room temperature without addition of photosensitizers. From the THF solution, the tris­(<i>o</i>-phenylenediamine) iron­(II) complex, [Fe^II(opda)₃]­(ClO₄)₂ (<b>1</b>), was isolated as a photoactive species, while the deprotonated oxidized species was characterized by X-ray crystallographic analysis, electrospray ionization mass spectrometry, and UV–vis NIR spectra. Furthermore, the HER is photocatalyzed by hydroquinone, which serves as a H⁺/e^– donor. The present work demonstrates that the use of a metal-bound aromatic amine as a H⁺/e^– pooler opens an alternative strategy for designing nonprecious-metal-based molecular photochemical H₂ production/storage materials