Syntheses, Structures And Properties Of Coordination Polymers Based On Semi-rigid Organic Ligands

As significant inorganic–organic hybrid materials,coordination polymers(CPs)have attracted much attention in the last two decades due to their various structures and charming performances.Selection of the metal centers and bridging ligands is important to control the structures and properties of target products.Six semi-rigid organic ligands are designed and sythenised.Then ten new CPs are obtained under hydrothermal conditions by utilizing these ligands mixed with various carboxylate ligands.The crystal stuctures of all CPs have been characterized by various methods.Further,the fluorescence,solid-state diffuse reflectance properties,and the photocatalytic behaviors for degradation of methylene blue(MB)are also investigated.Six Co(Ⅱ)/Ni(Ⅱ)-based CPs have been constructed from semi-rigid bis(imidazole)(L1,L2)and five different carboxylates.CP 1 is a 4-connected 2D sql network.2 exhibits a 3D 4-connected five-fold interpenetrating sqc6 topology.3 presents a 3D 6-connected pcu topological net.Both 4 and 5 show a 3D 4-connected dia topology with different sizes and interpenetrating numbers.CP 6 has a relatively rare 2D 3,4-connected 3,4L83 framework.The 2D layers of 1 and 6 are further extended into 3D architectures through hydrogen bonding interations.The combination of four semi-rigid bis(benzimidazole)(L3~L6)with two kinds of aromatic carboxylic acids,and Co(Ⅱ)/Mn(Ⅱ)centers construct four complexes.All of CPs 7,8 and 9 are 1D chain structures,which are eventually expanded into 3D,1D and 2D supramolecular network,respectively.10 is a classic pcu cubic structure.All CPs possess potential fluorescence and solid-state diffuse reflectance properties,indicating that CPs 1~10 can be used as optical materials,and all CPs display high thermal stabilities except 7.In addition,CPs 1,5,6,7 and 8 exhibit remarkable photocatalytic activities and repeatability in the degradation of MB.