Synthesis, Structures, Rare Earth Fluorescence Sensing And Magnetic Properties Of Coordination Compounds Constructed From Carboxylate Ligands

Metal-Organic Frameworks?MOFs?are coordination compounds with a highly ordered and regular infinite network structures formed by metal ions and organic ligands through coordination bond.Due to the diverse coordination mode of the carboxylate group,MOFs based on the carboxylic ligands often show great potential applications in gas storage and separation,molecular magnets and fluorescence sensing.Since MOF contain a variety of structural units that can be designed and modifiable,functional MOF composites can be obtained by a post-synthesis modification?PSM?approach.In this thesis,two MOFs?named JXNU-4 and ly?with the uncoordinated carboxylate oxygen atoms on the surface of the one-dimensional?1D?channels were selected as the parent frameworks for the MOF composites.Two novel MOF composites,Eu³⁺@JXNU-4?1?and Eu³⁺@ly?2?were obtained by incorporating the Eu³⁺with good fluorescence into the MOF frameworks through the PSM method.The two MOFs are characterized by the powder X-ray diffraction,inductively coupled plasma-mass spectrometry?ICP-MS?,and X-ray photoelectron spectroscopy?XPS?,which show the Eu³⁺ions are incorporated into the MOFs and captured by the uncoordinated carboxylate oxygen atoms on the 1D channels of the parent frameworks.In addition,the three-dimensional?3D?frameworks are intact after incorporated the Eu³⁺ions.The detailed fluorescence sensing properties of the MOF composites were investigated.The results show that the Eu³⁺@JXNU-4?1?acts as a fluorescent probe for urine 1-hydroxypyrene?1-HP?,which is a biomarker of polycyclic aromatic hydrocarbons?PAHs?carcinogens,with a high selectivity and without the interference by other coexisting species in urine.The Eu³⁺@JXNU-4?1?is the first ratiometric fluorescent MOF sensor for detecting of 1-HP,which broadens the appliactions of the MOFs.Additionally,the fluorescence intensity of the Eu³⁺@ly?2?are enhanced withthe concentration of the hippuric acid increasing,which indicates that the Eu³⁺@ly?2?can be a fluorescent MOF sensor for detecting of hippuric acid.In the second part of this thesis,three coordination polymers constructed from the large magnetic anisotropy Co???ions and long 4,4'-dicarboxydiphenylsulfone?H₂DCDPS?ligand.The carboxylate groups of the 4,4'-dicarboxydiphenylsulfone are expected for bridging the Co???ions to form the 1D Co???-carboxylate chains.Moreover,the long skeleton of the 4,4'-dicarboxydiphenylsulfone will separate the 1D Co???-carboxylate chains spatially,which provides magnetically isolated chains,facilitating the formation of single-chain magnets?SCMs?.These coordination polymers are listed below.{[Co₃??₃-OH?₂?DCDPS?₂?H₂O?₄]·3.5?H₂O?}_n?3?{[Co_3.5??₃-OH??DCDPS?₃?H₂O?₄]?CH₃CN?2?H₂O?}_n?4?{?H₃O?₂[Co₅?DCDPS?₆]·2?H₂O?}_n?5?These compounds are characterized by the single-crystal X-ray diffraction,powder X-ray diffraction?PXRD?,thermogravimetric analysis,and infrared spectroscopy.The result of the single-crystal X-ray diffraction reveals that compound3 is a two-dimensional?2D?bilayered structure containing the 1D hydroxyl-bridged Co???chains.The 1D hydroxyl-bridged Co???chains in 3 are separated by the long4,4'-dicarboxydiphenylsulfone ligands.The 2D layer features the 1D channels due to the V-shaped conformation of the 4,4'-dicarboxydiphenylsulfone ligands.The detailed magnetic study show that compound 3 is a SCM.Compound 4 is a 3D structure based on the hexanuclear Co???cluster formed from two fused trinuclear Co???clusters.In4,the hexanuclear Co???cluster units are linked by the 4,4'-dicarboxydiphenylsulfone ligands to give a 3D framework.The 3D compound 5 contains the pentanuclear Co???cluster units.Thus compounds 4 and 5 are not based on the 1D Co???chanis.The Co???ions in compounds 4 and 5 exhibit a antimagnetic interactions.This thesis is divided into the following four parts:The first chapter is the foreword,which mainly introduces the development history of metal-organic framework compounds,briefly describes the research progress of the metal-organic framework materials in the aspects of fluorescence sensing and magnetic properties,and the main idea of this thesis.In the second chapter,the synthesis and characterization of two MOF composites1 and 2 were introduced and the fluorescence sensing properties these two MOF composites were tested.In the third chapter,the synthese,structures and magnetic properties of three coordinationcompoundsconstructedfromtheCo???ionsand4,4'-dicarboxydiphenylsulfone ligand are presented.The fourth chapter summarizes and prospects this work of this thesis.