Crystal structures and spectral properties of two polyoxometalate-based inorganic–organic compounds from silver–azine building blocks with bis-bidentate and tridentate ligands

•Two novel POM-based compounds have been synthesized with silver–azines.•The compounds have been characterized by IR, UV, XRPD and elemental analysis.•X-ray single-crystal structure analyses and discussion for the compounds.•The two compounds exhibit fluorescent emission in solid state, respectively.

Two polyoxometalate-based inorganic–organic hybrid compounds constructed from silver(I)-L species and saturated Keggin type polyoxoanion, [Ag2L21]2(SiMo12O40)·1.5DMF·0.5CH3OH⋅H2O 1 and [{Ag4L22(DMF)5}(SiMo12O40)] 2 (L1 = phenyl 2-pyridyl ketone azine, L2 = 3-phenyltriazolo[1,5-a]pyridine), have been synthesized and structurally characterized by IR, UV, elemental analysis, XRPD and complete single crystal structure analyses, where the ligands L1 and L2 are bis-bidentate and tridentate azines synthesized with the same materials under different conditions. The structure of 1 exhibits a dinuclear double-helicate with [SiMo12O40]4− anions as counter ions, where all of the Ag centers coordinate to bis-bidentate chelating ligands. Compound 2 displays a two-dimensional sheet formed by the Ag–organic infinite chains and the [SiMo12O40]4− alternately arranged in a “rail-like” fashion. The luminescent properties of 1 and 2 in the solid state were investigated.

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