A series of polyoxometalate-based compounds including infinite Ag belts and circles constructed by two tolyl-1H-tetrazole isomers

Abstract

In this paper, three new polyoxometalate (POM)-based metal–organic compounds containing silver cycles/belts, namely, [K₂Ag₁₅(L₁)₁₀(H₂O)₂][H(PMo₁₁^VIMo^VO₄₀)₂] (1), [Ag₇(L₁)₄][PW₁₂O₄₀]·2H₂O (2) and [Ag₁₀(L₂)₈(H₂O)][PW₁₂O₄₀] (3) (L₁ = 5-o-tolyl-1H-tetrazole, L₂ = 5-m-tolyl-1H-tetrazole), have been obtained under hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR spectra and powder X-ray diffraction (PXRD). The organic molecules L₁ and L₂ are isomeric. In compound 1, there exist two dimensional (2D) Ag-L₁ layers including Ag belts, which are further linked by Ag5 to form a 3D metal–organic framework (MOF). The inorganic chain in 1 with Keggin anions linked by Ag1 ions insert into the channels of this 3D MOF. In compound 2, the Ag-L₁ belts are connected by Keggin anions to construct a 2D layer. Adjacent layers link with each other through Ag–O bonds and the 3D framework of 2 is thus built. In compound 3, the 2D Ag-L₂ layer possesses Ag cycles. Adjacent layers are linked by Ag–N bonds and Keggin anions to form the 3D structure of 3. The influence of the types of POM anions and organic ligands on the final structures was discussed. Furthermore, the electrochemical, photocatalytic and fluorescent properties of compounds 1–3 were investigated.