pH-value-controlled assembly of photoluminescent zinc coordination polymers

By pH-value adjustment, the reactions of zinc salt, 1,3,5-benzenetricarboxylic acid (H3btc) and 4,4′-bipyridine (bpy) yield three coordination polymers, formulated as [Zn3(btc)2(bpy)(H2O)2]n (1), [Zn(Hbtc)(bpy)(H2O)]n · 3nH2O (2) and [Zn(Hbtc)(bpy)(H2O)]n · 4nH2O (3), respectively. The structure of 1 is a 3D network containing channels filled with bpy ligands. Compound 2 consists of twofold interpenetrating (10,3)-b networks, while compound 3 is a 2D layer structure. The fluorescent studies reveal that they exhibit intense violet luminescence in solid state.

The tailored hydrothermal reactions between zinc salt, H3btc and bpy ligands yield three coordination networks with different structural motifs: a 3D network with filled channels, twofold interpenetrating large (10,3)-b networks and a 2D layer, respectively. The result demonstrates that pH value plays an important role during the assembly process.Figure optionsDownload as PowerPoint slide