Three silver coordination polymers constructed from 4,4′-bipyridine-like ligands and 2,5-thiophenedicarboxylic acid: crystal structures and photocatalytic performances

Three coordination polymers (CPs), formulated as [Ag(bpy)]2(tdc)·4H2O (BUC-78), [Ag(bpe)]2(tdc)·6H2O (BUC-79) and [Ag(bpp)]2(tdc)·8H2O (BUC-80) have been synthesized from the reactions between AgNO3, 4,4′-bipyridine (bpy),1,2-bis(4-pyridyl)ethylene (bpe),1,3-bis(4-pyridyl)propane (bpp) and 2,5-thiophenedicarboxylic acid (tdc) by slow evaporation at room temperature. The X-ray crystal structures of all three CPs were determined, revealing that they are all comprised of 1D infinite cationic [Ag(L)] chains interspersed with discrete deprotonated tdc2− counterions. These CPs exhibit good photocatalytic performances for the degradation of methylene blue and rhodamine B, giving up to 97% degradation under UV irradiation within 120 min. A possible photocatalytic mechanism is proposed, based on the results of active species capture experiments.