Synthesis,Structure And Fluorescence Properties Of Coordination Polymers Based On Carboxylic Acid

Coordination polymers have become one of the fastest growing chemical fields due to their diverse structure and huge potential application prospects.In the process of assembling the coordination polymers,the metal ions,organic ligands,reaction temperature,pH and the molar ratio of the components are all factors that affect their structural diversity.In this paper,different carboxylic acid organic ligands have been selected to self-assenble with metal ions,as a rusult twelve coordination polymers have been synthesized by hydrothermal method and characterized by IR spectra,elemental analysis,X-ray single crystal diffractions and X-ray powder diffractions,and the properties of magnetism and fluorescence recognition of some coordinated polymers have been also studied.The main contents are as follows:1.Threenovelcoordinationpolymershavebeenobtainedbasedon4'-?4-?4-carboxylphenoxy?phenyl?-2,2':6',2''-Terpyridine?HCPP?,which are[Mn?CPP?₂?H₂O?]_n?1?,[Cd?CPP?₂?H₂O?]_n?2?,[Zn?CPP?₂?CO₃??ClO₄??H₂O?₂]_n?3?.All of them are three-dimensional structures constructed by?···?stacking interactions.Compound 1 and 2 are isomorphous and isostructure,which are coordinated with nitrogen and oxygen atoms of the CPP^-ligand to form an infinite one-dimensional chain;Compound 3 is a binuclear coordination polymer with a two-dimensional layer connected by CPP^-ligand,and adjacent layers are further constructed into three-dimensional structure via?···?interactions between the benzene rings.Coordination polymer 1 has antiferromagnetism,coordination polymer 2 has a good fluorescence recognition on Cu²⁺ion and coordination polymer 3 exhibits good fluorescence enhancement response to tryptophan and can be used as probe for detection.2.Two coordination polymers have been solvothermally synthesized based on4'-?4-?3,5-dicarboxylphenoxy?phenyl?-4,2':6',4''-terpyridine?H₂DPT?,namely,[Ni?DTP??H₂O?]_n?4?and[Cd₂?DTP?₂?bibp?_1.5]_n?5??bibp=1,3-di?1H-imidazol-1-yl?propane?,which present structural diversity.they consist of{NiN2O4}building units?for 4?,{Cd O4N2}and{CdO3N3}building units?for 5?,which are further bridged by the multicarboxylate ligands to construct microporous three-dimensional frameworks,respectively.Coordination polymer 4 is with the rhombic channels with the dimension of 19.4382×14.2392?² and exhibits antiferromagnetism.Coordination polymer 5 demonstrates highly selective and sensitive bifunctional luminescent sensor towards nitrobenzene and Cu²⁺ion.The fluorescence quenching mechanism of 5 caused by nitrobenzene is attributed to the electron-transfer from the electron-rich coordination polymer 5 to the electron-deficient nitrobenzene,which has been evidenced by the density functional theory?DFT?.3.based on 2-?3',4'-dicarboxylphenoxy?isophthalic acid?H₄dpc?and 4-?5-sulfonyl quinolin-1-ium-8-yloxy?phthalic acid?H₃pc?have been selected to coordinate with metal cadmium,and four different coordination polymers have been obtained,namely,[Cd₂?dpc??bip??H₂O?₃]_n?6??bip=4'4-bipyridine??{[Cd₂?dpc??bib??H₂O?]·H₂O}_n?7??bib=1,4-bis?1-imidazoly?benzene??{Cd₂[?dpc??bitb?_1.5?H₂O?₂]·H₂O}_n?8??bitb=1,4-bis?imidazol-1-ylmethyl?benzene??[Cd₃?spc?₂?bitb?₂]_n?9?.Coordination polymers 6-8 are binuclear coordination polymers,6 and 8 are formed by covalent bond with nitrogen-containing ligand to form three-dimensional framework,while three-dimensional structure of coordination polymer 7 is formed by C-H···?interactions;9 is a three-core coordination polymer,with spiral structure of the one-dimensional chain,through the?···?stacking to build three-dimensional structure.The coordination polymer 6 demonstrates a good recognition on lysine,while the coordination polymer 8 has highly selective luminescent sensor towards Fe³⁺ion.4.Three coordination polymers have been prepared via hydrothermal process based on4,5-di?3'-carboxylphenyl?-phthalic acid,namely,{[Mn?ttac?·?bibp?·H₂O]·[bibp]·H₂O}_n?10??bibp=4'4-bis?imidazolyl?biphenyl??{[Co?ttac?_0.5?1,4-bib?]·2H₂O}_n?11??1,4-bib=1,4-bis?1-imidazoly?benzene?and[La?Httac?₂?H₂O?]n?12?.Coordination polymers 10presents a 1D uniform Mn-carboxylate chain,meanwhile,two central Mn?II?atoms are bridged by bibp ligands end to end,forming a 2D layer in this way.These 2D sheets are further stacked with each other via?···?interactions to generate a 3D porous network owing to the existence of guest bibp molecules,and there are water molecules in the cavities.Coordination polymers 11 is assembled from low-dimensional structures into three-dimensional?3D?via?···?stacking interactions,while three-dimensional coordination polymer 12 is formed by covalent bonds.Luminescent properties of coordination polymer 12 has been studied at ambient temperature,Significantly,the emission intensities coordination polymer 12 change obviously in the presence of Cu²⁺and Mn²⁺ion.