Keggin POM-based 3D framework tuned by silver polymeric motifs: structural influences of tetrazolate functional groups

Abstract

By altering the functional groups of tetrazolate ligands in the same Ag–POM reaction system, two novel inorganic–organic hybrids: [Ag₇(L₁)₄(H₂O)(PMo₁₂O₄₀)] (1) and [Ag₅(L₂)₂(PMo₁₂O₄₀)]·H₂O (2) (HL₁ = 5-(4-imidazol-1-yl-phenyl)-2H-tetrazole, HL₂ = 5-(4-triazol-1-ylmethyl-phenyl)-2H-tetrazole), have been synthesized under hydrothermal conditions, which are characterized by single crystal X-ray diffraction, IR spectra and elemental analyses. Compounds 1 and 2 both display POM-based 3D frameworks modified by different Ag–tetrazolate motifs. In compound 1, a beautiful POM-inserted 2D network is formed by {Ag₆(L₁)₄}_n chains and POM polyoxoanions, which are linked to each other through covalent bonds into a (6,6,10)-connected 3D framework. The 3D framework of compound 2 is constructed from chains of circle-connecting-circle and dimeric polyoxoanions. The different structural features of the two compounds suggest that the functional groups of tetrazolate ligands should play a key role in the process of assembly. The luminescent properties for compounds 1 and 2 are investigated.