Self-assembly of iron coordination polymer of bowl-shaped N-ligand and dodecamolybdosilicate anion

• A supramolecular compound with [SiMo12O40]4− anion was hydrothermally synthesized.
• Coordination of bowl-like N-ligand to Fe1 ions forms a chain with small cages.
• A bowl-like N-ligand ligand bridges Fe2 ions forming a layer with uniform grids.
• The formation of the compound quenches the intra-ligand fluorescent emission.

[FeII2(ttmb)2(H2O)6][SiMo12O40]·4H2O (1) (ttmb = 1,3,5-tris(triazol-1-ylmethyl) benzene) was synthesized under hydrothermal conditions and characterized by IR spectroscopy, TG analysis and X-ray diffraction method. In 1 the bowl-like tridentate ligand, ttmb, bridges Fe2+ ions forming a coordination polymeric layer, [FeII2(ttmb)2(H2O)6]n4n+, with a large dimensional grid of 7.00 × 7.11 Å, in the presence of Keggin-type polyoxoanion as a template. The coordination polymeric layers and the polyoxoanions are fused into an inorganic–organic hybrid by hydrogen bonds. The photoluminescent spectrum of 1 in solid state at room temperature shows that the coordination of ttmb to Fe2+ ion results in a quench of the ttmb intramolecular fluorescence and a weak O–Mo LMCT fluorescent emission was observed at 520 nm.

A new Keggin polyoxoanion-templated inorganic–organic hybrid with a layer structure is constructed from iron-bowl-shaped N-ligand polymeric cation layer [FeII2(ttmb)2(H2O)6]n4n+ and SiMo12O404− anions. The grids in the layer is not big enough to envelop the [SiMo12O40]4− anion so that the anion is considered as a non-coordinating inorganic template.Figure optionsDownload as PowerPoint slide