Two novel structures based on an organic ligand with two different coordination modes

Abstract

Two novel organic–inorganic hybrid compounds, namely [Ag₆(bzmd)₂][SiW₁₂O₄₀] ·H₂O (1) and [Ag₂(Hbzmd)₂][HPW₁₂O₄₀] (2) (Hbzmd = 1-(p-(tetrazol-5-yl)benzyl)-2-(pyrid-2-yl)benzimidazole), have been synthesized and characterized by IR, UV, powder XRD, EDS, TG, cyclic voltammetry analysis, photoluminescent analysis, elemental analyses and single crystal X-ray diffraction. The two compounds represent two novel 3-D structures constructed from Keggin polyanions, metals and organic ligands. It should be noted that compound 1 is based on polyoxometalates, silver and bzmd⁻ ligands, whereas, compound 2 is based on polyoxometalates, silver and Hbzmd ligands. The bzmd⁻ ligand in compound 1 and the Hbzmd ligand in 2 exhibit distinctly different coordination modes. Silver and bzmd⁻ ligands form a 3-D framework via Ag–N and Ag–π interactions in compound 1. Compound 1 also contains a pure inorganic 3-D framework, and then the two kinds of frameworks in compound 1 are fused into an unprecedented 3-D structure. Silver and Hbzmd ligands form a 2-D framework via only Ag–N interactions in compound 2, moreover, polyoxometalates in compound 2 are linked by silver into a novel pure inorganic 2-D framework, and then two kinds of frameworks are further fused into a novel 3-D structure. In conclusion, two different 3-D frameworks and two different 2-D frameworks are respectively fused into two novel 3-D structures constructed from polyoxometalates, metals and organic ligands (POMMOFs).