Two manganese(II) complexes constructed from 2-(3-pyridyl)-imidazo[4,5-f] 1,10-phenanthroline and organic dicarboxylates: syntheses, crystal structures, and luminescence

Simultaneous Cr(VI) reduction and Cr(III) removal of bifunctional MOF/Titanate nanotube composites

In this study, a series of BUC-21/titanate nanotube (BT-X) composites were facilely fabricated via ball-milling of 2-dimensional (2D) metal-organic framework (MOF) BUC-21 and titanate nanotubes (TNTs). The BT-X composites were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), UV-visible diffuse-reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectrometer (XPS) and high resolution transmission electron microscopy (HRTEM). Both the photocatalytic reduction from Cr(VI) to Cr(III) and adsorptive removal of formed Cr(III) of BT-X composites were systematically investigated under different conditions including pH values and co-existing inorganic ions. It was found that BUC-21 (100 mg)/TNTs (100 mg) (BT-1) composites demonstrate remarkable ability of photocatalytic Cr(VI) reduction and adsorptive Cr(III) removal, as well as good reusability and stability. It is believed that the introduction of TNTs could capture the formed Cr(III) from the surface of BUC-21, which provided more active sites exposed to enhance the Cr(VI) reduction.

Synthesis, structures and properties of six lanthanide complexes based on a 2-(2-carboxyphenyl)imidazo(4,5-f)-(1,10)phenanthroline ligand

Six lanthanide complexes [Tb(2-NCP)₂(NO₃)]_n (1), [Eu(2-NCP)₂(3-PYC)]_n (2), [Sm(2-NCP)₂(3-PYC)]_n (3), [Eu(2-NCP)(SA)]_n (4), [Tb(2-NCP)(SA)]_n (5) and [Tb(2-NCP)(AA)]_n (6) (2-HNCP = 2-(2-carboxyphenyl)imidazo(4,5-f)-(1,10)phenanthroline, 3-HPYC = pyridine-3-carboxylic acid, H₂SA = succinic acid, H₂AA = adipic acid) have been synthesized by hydrothermal route, and the crystal structures were analyzed through elemental analysis, infrared spectroscopy, single crystal X-ray diffraction. Complexes 1 and 6 present two-dimensional (2D) layers, which are further connected to three-dimensional (3D) supramolecular architectures through C–H⋯π interactions. Complexes 2 and 3 exhibit infinite one-dimensional chains. Finally, the neighboring chains are packed by C–H⋯π interactions, giving rise to 3D supramolecular network. Complexes 4 and 5 display 2D layers, which are further extend to 3D supramolecular structures via C–H⋯O intermolecular hydrogen bonding. Six complexes possess good thermal stabilities, characteristic photoluminescence properties, and photocatalytic activities for the degradation of organic dyes under visible light irradiation. In addition, the complex 6 exhibits significantly enhanced photocatalytic activity for methylene blue, and the degradation rate could reach 81.2% in 370 min. Meanwhile trapping experiments indicated that the hole, ·O₂⁻ and ·OH are the main activated species. Furthermore, by comparing the photoluminescent and photocatalytic mutation results of same metal complexes induced by interconversion of coligands, we confirm that the properties mutation induced by coligands is much obvious and controllable.

Six lanthanide complexes based on 2-HNCP possess good thermal stabilities, characteristic photoluminescence properties, and photocatalytic activities for organic dyes degradation under visible light irradiation.