Syntheses And Structures Of Mn,Co,Cu,Zn,Cd-Coordination Polymers Based On The Flexible Aromatic Carboxylic Acid Ligand H₂cboa And Differert N-Containing Heterocyclic Ligands

Metal-organic coordination polymers(MOFs),as functional materials with easily designed structures and adjustable properties,are of great significance in the fields of gas storage separation,proton conduction,catalysis,fluorescent probes,and magnetism.In this paper,the flexible 3-(carboxymethoxy)benzoic acid(H₂cboa)is used as the main ligand.(1)The flexible bis-nitrogen-heterocyclic 1,4-bis((1H-imidazol-1-yl)methyl)benzene(bmb)was selected as the auxiliary ligand.And five transition metal organic coordination polymers(Cu²⁺,Mn²⁺,Cd²⁺,Co²⁺,Zn²⁺)with novel structures have been designed and synthesized by solvothermal method in PTFE reactor,and the point symbols and topological types of these complexes were analyzed by topospro software.X-ray single crystal diffraction(XRD)analysis showed that the structures of coordination polymers 1-5 are 2D layered structures.Coordination polymers 4 and 5are triple-fold interpenetrating 2D layered structures and their channels are occupied by water.(2)The more distorted flexible N-containing 1,4-bis(1H-imidazol-1-yl)butane(dbi)as the auxiliary ligand.And four novel transition metal organic coordination polymers(Co²⁺,Cu²⁺,Cd²⁺,Zn²⁺)were synthesized in teflon reactor under solvothermal conditions,and their point symbols and net types were analyzed by topospro.X-ray single crystal diffraction(XRD)analysis of its structure shows that coordination polymers 6,8,and 9 are all three-dimensional frameworks,and coordination polymer 7 is a 2D layer.Coordination polymers 6 and 9 are four-fold interpenetrating 3D frameworks.The channels of coordination polymer 6 are occupied by methanol,and the channels of porous coordination polymer 9 are not occupied.These coordination polymers were characterized using FT-IR and PXRD.The effects of different metal centers,reaction temperature,p H and solvent polarity on crystal growth were analyzed.In this work,nine topologically rich Mn,Co,Cu,Zn,Cd-coordination polymers constructed from the flexible aromatic carboxylic acid H₂cboa and different N-containing heterocycles were successfully synthesized.The effects of the length and flexibility of different auxiliary ligand chains and the building units of MOFs on the crystal dimension and interpenetration degree were explored.In the construction of porous coordination polymers,the pore volume and porosity of crystals can be adjusted by changing the unit cell volume by changing the type of polar solvent.It provides theoretical support and material basis for further research on MOFs functional materials.