Syntheses, structures and photocatalysis properties of two Cu(II)-based coordination polymers based on flexible tricarboxylate ligand

• Two CPs with flexible tricarboxylate ligand and N-donor ligands synthesized. • 2 has excellent degradation ability of MB and conform the pseudo-first-order rate constant. • The intermediate products of catalytic process were traced. The photocatalytic performances of the two complexes were explored by the photodegradation of methylene blue (MB) dye under UV light. The chromatography-mass spectrometry (LC-MS) was selected to discuss the catalytic process, revealing the potential photodegradation mechanism of MB. Recycling experiments also indicated that the photocatalyst is reusable and stable. Two new Cu(II)-based coordination polymers (CPs), including [Cu(HL)(H 2 O)(2,2′-bipy)] ( 1 ) and [Cu(HL)(bbi)] ( 2 ) (H 3 L =5-(4ˊ-carboxylphenoxy)isophthalic acid, bbi=1,1′-(1,4-butanediyl)bis(imidazole) and 2,2′-bipy = 2,2′-bipyridine), have been successfully synthesized and characterized. 1 shows a 1D ladder-like chain that was further expanded into a 3D supramolecular network through packing interactions and H-bonded interactions. 2 also features an infinite chain containing [Cu(bbi) 2 Cu] loops. The photocatalytic performances of these polymers were explored by the photodegradation of methylene blue (MB) dye under UV light. 2 has excellent degradation ability of MB (50 mL and 10 mg L − 1 ) could be fully photodegraded within 100 min and follows with the pseudo-first-order rate constant. In addition, chromatography-mass spectrometry (LC-MS) was selected to discuss and analyze the catalytic process, suggesting the potential photodegradation mechanism of MB. Recycling experiments also indicated that the photocatalyst is reusable and stable.