Synthesis And Luminescent Properties Of Functional Coordination Polymers

Coordination polymers have attracted much attention in recent years due to their wide application prospects in the fields of information,energy and environment.Using organic molecules as bridging ligands,they self-assemble with metal ions through coordination bonds to form regularly ordered coordination polymers.It is possible to construct coordination polymers with excellent luminescence properties by design and regulation.At present,luminescent coordination polymers have been investigated and applied in luminescence sensing,thermometers,biomedicine,anticounterfeiting,and so on.The main contents of this paper are as follows:1.The approximate content of the coordination polymers,as well as the course of their development,are briefly discussed.The synthetic procedure of coordination polymers is described.The main components to construct coordination polymers with excellent luminescent properties and the applications of luminescent coordination polymers in chemosensing detection,thermometer,biological medicine,anticounterfeiting and other fields are illustrated.2.We selected NaH₂SIP as an organic ligand（NaH₂SIP=sodium isophthalate-5-sulfonate）to synthesize a series of novel Ln-CP（[Ln（SIP）（DMF）（H₂O）₄]DMF·H₂O,Ln=Eu,Tb,Sm,Dy）by solvothermal method.Eu-HS and Tb-HS showing high quantum yields of 13.70%and 42.38%,respectively.The co-doped Ln-CP obtained by doping with different ratios of Eu³⁺/Tb³⁺is an excellent ratiometric thermometer with high sensitivity in the physiological temperature range.The exhibited sensitivities were16.8%·K^-1,7.0%·K^-1,and 14.5%·K^-1,respectively.Moreover,the luminescent colors of the coordination polymers Tb_0.94Eu_0.06-HS and Tb_0.95Eu_0.05-HS exhibit a change from green,yellow,to orange red,enabling visual luminescence in a narrow temperature range.The composite thin film material Tb_0.95Eu_0.05-HS@PMMA demonstrated this color change.3.Lanthanide luminescent MOF（porous coordination polymer）materials show very remarkable luminescent properties.However,obtaining lanthanide luminescent MOFs with high quantum yields is a challenging study.A novel Bi-MOF（[Bi（SIP）（DMF）₂]）was synthesized by using NaH₂SIP and Bi（NO₃）₃·5H₂O.Thereafter,doped MOFs（Ln-Bi-SIP,Ln=Eu,Tb,Sm,Dy,Yb,Nd,Er）with different luminescence properties were obtained by in-situ doping with different Ln³⁺ions,among which Eu-Bi-SIP,Tb-Bi-SIP,Sm-Bi-SIP,Dy-Bi-SIP have high quantum yields.The Eu Tb-Bi-SIP and Dy-Bi-SIP obtained from Eu³⁺/Tb³⁺co-doping exhibited good temperature sensing performance in a wide temperature range,and the maximum sensitivity Sr was 1.6%·K^-1（433 K）and2.6%·K^-1（133 K）,respectively.Finally,considering the practical application value,Eu Tb-Bi-SIP was blended with organic polymer polymethylmethacrylate（PMMA）to make a thin film,which showed different color changes at different temperatures.4.There are reports on LMOFs mostly focusing on Ln³⁺as the central metal node,with less work on transition metal based LMOFs to date.Therefore,we synthesized two MOFs（Zn-DSD and Cd-DSD）using Zn²⁺and Cd²⁺with the ligand H₂L⁰（4,4’-diaminostilbene-2,2’-disulfonic acid）.The ligand H₂L⁰ contains-NH₂ as well as-SO₃groups.The coordination ability of the-SO₃ group is weak,and only the N atom on-NH₂ is coordinated.The final structure formed by bridging of the ligands is a 1D stepped chain structure.Surprisingly,due to the existence of hydrogen bonds between1D chains and between chains and solvents,different 3D supramolecular structures are formed by stacking through hydrogen bond interactions.After that,PXRD was utilized to characterize the purity as well as the crystallinity of the prepared material.Next,the thermal stability of Cd-DSD was tested.Finally,the luminescent properties of Cd-DSD were investigated.It exhibits strong blue light emission.5.We synthesized a new imine like（salicylaldehyde Schiff base derivative）ligand H₂L_F.Its structure was characterized by SCXRD.We found a significant visual change in its color from yellow to orange yellow upon irradiation by a 365 nm hand-held UV lamp.This photochromic behavior has good reversibility.Finally,a 1D chain-like coordination polymer（Zn-LF）was successfully prepared by self-assembly of Zn²⁺ions with H₂L_F based on the coordination ability of C=N with-OH groups.It exhibited a luminescent discoloration after grinding.After PXRD characterization means,this pressure induced luminescent discoloration behavior was proved to be reversible.