Study On The Properties Of Charge Transfer Complexes And Fluorescence Enhancement Materials Induced By Anion-Coordination With Oligo-Urea

Since the chemistry discipline pioneered the discovery of research fields beyond the molecules,a large number of scientists have begun to study and explore the discipline of‘Supramolecular Chemistry'.A large number of transition metal and spherical metal ions,organic cations,neutral and anions are used to construct supramolecular assemblies.With the development of supramolecular chemistry,anion coordination chemistry has also become one of the important research subjects.Among them,(thio)urea-containing anion receptors have attracted more and more scientists'attention because of their rational design and the effective assembly of anions with different shapes by the use of hydrogen bonding interaction.However,because it is relatively sensitive to supramolecular assemblies than cations,it has high requirements for ligand design and coordination environment.Therefore,it is necessary to design and synthesis of a class of supramolecular materials with special electrical and optical properties,and for the applications of anionic coordination assembly and need more extensive research and exploration.In chapter 1 of this thesis,the development of supramolecular chemistry and anion coordination chemistry is mainly described.At the same time,the applications of methyl viologen and its derivatives and tetraphenylethylene(TPE)groups in supramolecular assemblies are introduced.In chapter 2 of this thesis,we design and synthesize a class of cyclic crown ether tri-urea ligands,coordinate with the sulfate anion SO₄^2-,and introduce methyl viologen MV²⁺and its derivatives,trying to explore the electrical properties of the assembly with urea-containing anion receptors.Using tri-urea ligands as donors and methyl viologen MV²⁺and its derivatives as acceptors,the first anion coordination induced charge transfer supramolecular assembly was constructed by sulfate SO₄^2-coordination induction.Through the analysis of the X-ray single crystal structure,the study of solid diffuse reflectance spectroscopy and quantitative calculation of the obtained assembly,it was found that the energy band gap between the donor and the acceptor is related to the length of the cation substituent and the type of?-?stacking in the charge transfer complex.Among them,ligand L¹ and methyl viologen MV²⁺induced by sulfate SO₄^2-coordination to form an infinite long-range order?-?stacking complex 1a-II,the band gap between the charge donor and acceptor Narrower.In the chapter of this thesis,based on the charge transfer complex obtained in chapter 2,the charge transfer complex induced by anion coordination is simplified by the removing the part of crown ether and replace the terminal of tri-urea with a methoxy group.The simplified ligand L³ can also form infinite,long-range and ordered?-?stacking complexes with the sulfate of methyl viologen and its derivatives.And through the analysis of the X-ray single crystal structure of the complexes,the UV-Visible spectrum,the solid diffuse reflectance spectrum,the calculation of the Charge Displacement Curve(CDC)and the measurement of the electrical conductivity,the effect of different substituents viologen derivatives and the different anions induction on the formation of charge transfer complexes with higher conductivity were verified.In chapter 4,the tetraphenylethylene(TPE)group with excellent aggregation-induced emission(AIE)properties is selected as the linker of the C₂ symmetric bis-(bis)urea anion receptor.In the synthesis process,using the cis-trans isomers from the carbon-carbon double bond of tetraphenylethylene(TPE),two ligands of trans-tetraphenylethylene(TPE)bis-(bis)urea L⁸ and cis-tetraphenylethylene(TPE)bis-(bis)urea L⁹ were synthesized.In the assembly of trans-tetraphenylethylene(TPE)bis-(bis)urea L⁸ and sulfate or phosphate,through an X-ray single crystal structure analysis,fluorescence spectroscopy,¹H NMR spectra and high-resolution mass spectrometry,we explored the anion-coordination and by adding other guests to realize the process of stepwise fluorescence enhancement.The cis-tetraphenylethylene(TPE)bis-(bis)urea ligand L⁹ is induced by the coordination of phosphate anions to form the expected triple-helix cage structure with aggregation-induced emission properties,and by the induction of chiral choline guests,single chiral triple helix cage.Meanwhile,through the X-ray single crystal structure analysis,fluorescence spectroscopy,¹H NMR 1D and 2D DOSY spectra,high-resolution mass spectrometry research,to study and characterize the anion coordination induced assembly of the triple helix cage,single-stranded racemate helix,chiral triple helix cage with aggregation induced emission(AIE)properties.The chiral triple helix cage was characterized by circular dichroism(CD)spectroscopy and SEM morphology experiments,which provided the possibility for the anion-coordination assembly to be further applied to circularly polarized luminescence(CPL)materials.