Synthesis Of Luminescent Terpyridine Complexes And Their Responsiveness To Stimulation By Environmental Factors

The industrial development has brought about new challenges to environmental issues.Facing the large variety of environmental pollutants,environmental monitoring plays a vital role.Among various detection methods,fluorescence-based chemical detection is superior to others.Metal complexes,as a novel luminescent material,possess advantages such as long fluorescence lifetime,good stability,and low background interference.Among them,terpyridines and its derivatives are widely used in the field of metal coordination,forming stable complexes with various transition metal ions.These complexes can be applied in catalytic adsorption,stimuli-responsive materials,optical information storage,biological imaging and other fields.In this article,a series of metal-organic supramolecular structures were designed and synthesized based on the terpyridine-metal ion coordination-driven effect,and specific functionalities were imparted to the complexes by introducing different stimuli-responsive groups,which exhibited potential applications in environmental fields.The article is divided into two parts:In the first part,ligand with a large conjugated containing terpyridine groups and carbazole groups were designed and synthesized.These complexes exhibited different luminescence properties in solid and solution states.By adjusting the length of the alkyl chain within the ligand molecule,the structure of the complex formed with the metal Zn²⁺and its photophysical properties in response to environmental factors are controlled.The structure was characterized by ¹H-NMR,¹³C-NMR,2D-NOESY and2D-COSY,and the optical properties of this series of complexes were studied by UV-visible spectrometer and fluorescence spectrometer.It was found that this emission system has two charge transfer emission peaks due to its distorted molecular conformation,which can respond to solvent polarity and excitation light wavelength,making it exhibit different luminescence behaviors.This kind of fluorescence material that responds to different external stimuli can open up more possibilities as a luminescent device in fluorescence detection and has shown new potential in the field of environmental monitoring.This kind of material that produces fluorescence response based on external stimuli can be used as a fluorescence probe for specific recognition and other aspects.It has great application prospects in environmental monitoring and other fields.In the second part,by utilizing the template effect of the terpyridines ligand and metal ions coordination and other non-covalent interactions,hydrophobic aromatic structures with the terpyridines group were connected to hydrophilic side chains with specific functionalities.A hierarchical self-assembly strategy in solution was employed to synthesize three-dimensional metal supramolecular structures Zn L3 and Zn L4₂with hydrophobic cavities.This amphiphilic supramolecule can spontaneously form hollow tubules with hydrophilic exteriors and hydrophobic interiors in aqueous solution.The hydrophobic cavity can encapsulate aggregation-induced emission（AIE）molecules and Nile red dye molecules,leading to changes in their photophysical properties,while the external polyethyleneimine chains confer p H-responsive properties to the multi-level assembly and induce structural changes.By introducing stimulus-responsive functional groups,the strategy endows the multi-level assembled structure with stimulus-responsive characteristics,which opens up a new path for constructing new environmental response functional materials.This type of material has huge potential applications in environmental detection,biomedical,information security,and other fields.