Two new silver triazole frameworks with polyoxometalate templates

Abstract

Two new polyoxometalate-templated organic–inorganic hybrid compounds with different metal–organic frameworks, [Ag₅(trz)₆][H₄PMo₁₂O₄₀] (1) and [Ag₁₀(trz)₈][HPMo₁₂O₄₀] (2) (trz = 1,2,4-triazole), have been prepared based on the same organic ligands under different pH values. Compound 1 exhibits a honeycomb 2D [Ag₅(trz)₆] network and 3D graphite-like hybrid framework, and compound 2 exhibits a 3D {Ag₃[Ag₆(trz)₆][Ag(trz)₂]} framework with 2D channels, in which [PMo₁₂O₄₀]³⁻ polyanions locate in the center of channels. To the best of our knowledge, [PMo₁₂O₄₀]³⁻ polyanions represent the highest coordination number in 1 and terminal oxygen coordination number in 2 of Keggin POMs up to date. A comparison of two compounds demonstrates that the coordination mode of 1,2,4-triazole ligands and Keggin POMs templates have important influences on the assembly of different frameworks. In addition, compounds 1 and 2 exhibit good photocatalytic degradation of Rhodamine-B, and are very stable and easily recyclable as well.