Synthesis, structure and photocatalysis properties of two 3D Isostructural Ln (III)-MOFs based 2,6-Pyridinedicarboxylic acid

Two new 3D metal–organic frameworks (MOFs) named [Pr2(PDA)3·3H2O]·H2O (1) and [Nd2(PDA)3·3H2O]·H2O (2) [2,6-Pyridinedicarboxylic acid (H2PDA)] were synthesized by solvothermal method. They were characterized by elemental analyses (EA), infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), photocatalysis performance and single crystal X-ray diffraction studies (XRD). The XRD analysis indicated that MOFs (1) and (2) both belong to the monoclinic system with space group P2(1)/C. The structural model were drawn by the diamond software, and the structure revel that MOFs (1) and (2) adopt three-dimensional (3D) frameworks constructed by cross-linking of one-dimensional (1D) infinite chain secondary building unit (SBU) by 2,6-Pyridinedicarboxylic acid and hydrogen bond as linker. These frameworks feature channels inside which coordinated H2O solvent molecules are located. Thermogravimetric analysis showed that both MOFs are thermally stable, the photocatalytic evaluation showed the materials have a good prospect in degration methylene blue. As for complex 1, the decomposition efficiency of Methylene blue was about 91.08% after 130 min and the complex 2 reach 90.45% after 160 min under the sun light.