Stable Indium-Pyridylcarboxylate Framework: Selective Gas Capture and Sensing of Fe Ion in Water.

By employing a pyridyl-decorated dicarboxylic acid ligand, 3-(2',5'-dicarboxylphenyl)pyridine acid (Hdcpy), a three-dimensional In-based metal-organic framework, HO[In(dcpy)(OH)]·3DMF·4HO (1), with a good chemical stability toward acid and base has been synthesized. The compound 1 shows an uncommon (3,8)-connected tfz-d; UO topological net based on linear In(COO)(OH) clusters and also contains one-dimensional open channels. Particularly, 1 contains two types of dcpy linkers, in which the pyridyl group in one participates in coordination with the In ion, whereas that in the other is uncoordinated but hangs in the inner sides of the channels as functionalized sites. Gas adsorption experiments demonstrate that 1 is able to selectively adsorb CH, CH, and CO over CH. Simultaneously, 1 shows a highly selective and sensitive fluorescence detection toward Fe ion in water with good recyclability.