Photo-assisted synthesis of inorganic polyoxovanadate

Abstract

Photosynthesis plays a vital role on earth and photo-induced organic reactions have artificially created many valuable materials. However, the photo-induced syntheses of inorganic compounds are much less reported. Herein, we report the photo-assisted synthesis of a mixed-valence polyoxovanadate with the formula [C₉H₁₄N]₆[V₁₅O₃₆Cl], under AM1.5 irradiation in a N₂ atmosphere. Single-crystal X-ray diffraction analysis reveals a hexagonal structure (space group P6₃/mmc) with cell parameters: a = 14.1100(6) Å, b = 14.1100(6) Å, c = 22.0265(10) Å, and V = 3797.8(4) ų. UV-Vis and EPR analyses verified that the [V₁₅O₃₆Cl]⁶⁻ cluster formed within 0.5 h; powder XRD results indicated that the crystalline phase appeared after irradiation for 9.5 h (200 mW cm⁻²). These findings suggested that the nucleation and crystallization processes took longer than [V₁₅O₃₆Cl]⁶⁻ cluster formation and dominated the [C₉H₁₄N]₆[V₁₅O₃₆Cl] crystal formation. This primary work could open the door for the syntheses of inorganic compounds using photo-assisted reactions instead of conventional thermo-driving syntheses.