From 2D To 3D: Synthesis And Properties Of Layered Terpyridine-Metal Supramolecules

Environmental organic pollutants have great toxicity,wide sources,easy enrichment and great harm to human beings.For the identification and detection of organic pollutants,the effect of traditional methods is limited.The development of terpyridine-transition metal coordination-driven supramolecular systems has led chemists to construct many two-and three-dimensional metal supramolecular structures with precise geometrical configurations over the decades.Tribipyridine supramolecules with specific spatial structure and properties synthesized by careful design can specifically identify organic molecules in the environment,which has a wide application potential in the detection of environmental pollutants.In this paper,a series of two-dimensional layered structures were synthesized by careful design Threedimensional supramolecular structure and multistage assembly behavior of dye molecules of environmental pollutants are studied,and the corresponding photophysical properties are studied.The fluorescence sensing behavior of environmental pollutant nitrophenol with two supramolecular structures was studied.The specific research content is as follows:(1)Part I:Targeting the structural and charge characteristics of the water-soluble anionic dye(rhodamine B),we rationally designed triplet pyridine ligands with luminescent groups,and used multi-component self-assembly to precisely synthesize striped wheel-like supramolecules that can recognize rhodamine B.The supramolecular structures were characterized and confirmed utilizing NMR and mass spectrometry.The ability of the positively charged self-assembled framework to encapsulate the anionic dye was confirmed by spectroscopic and mass spectrometric techniques,leading to the preparation of the nanosystem.The system contains three luminescent centers,namely pyrene,tpy-Cd coordination framework,and the dye anion this rhodamine B.This multi-emission system takes full advantage of the inter-tuning effect of AIEE,ACQ and FRET to display a wide range of emission colors including near-white light,with the advantages of broad-spectrum and recognition visualization,providing an evidence base for the identification of rhodamine B.(2)Part II:The layered supramolecular cage structure was designed and synthesized.The structure of the supramolecular cage was characterized by 1H NMR,DOSY NMR,ESI-MS,TWIM-MS and TEM.The synthesis of hollow cages enables the precise assembly of complex multi-group alloyers and metals.Due to the large cavity with specific structure in the supramolecular cage,it has the potential to identify large environmental organic pollutants,so as to realize the detection of this type of environmental pollutants.(3)Part III:highly symmetric tetradentate organic ligands were designed and synthesized,and then assembled with metal Zn2+in a precise stoichiometric ratio to precisely synthesize the bilayer pentacyclic supramolecular structure,and the detailed structural characterization of the bilayer supramolecular cage was carried out by NMR and ESI-MS.The bilayer pentacyclic supramolecule contains D-A structural units with charge-transfer fluorescence emission properties;meanwhile,the complexes have high fluorescence quantum efficiency due to the rigid structure.Based on these two points,the fluorescence sensing performance of the supramolecular structure for environmental organic pollutants(nitroaromatic pollutants,4-nitrophenol)was further developed,so as to realize the detection of nitroaromatic pollutants in the environment.This study provides a new idea for the detection of nitroaromatic environmental pollutants by tribipyridine supramolecules.