Study On Synthesis And C₆₀ Binding Properties Of Anthracene-Based Urea Receptors

Fullerenes have attracted wide attention due to both the unique physical and chemical properties,as well as the wide applications in many research fields.In this paper,the binding of fullerene C₆₀ to anthracene-based urea receptor and anion coordination self-assembly structure was studied.Two kinds of urea-based receptors are described in this thesis.One is the tren-based tripodal with anthracene receptors.The other is bis-urea receptors based on anthracene groups with different terminal substituents.This thesis is divided into three chapters.The first chapter summarizes the development of anion coordination chemistry,the literature works in urea-based anion receptors and anion coordination self-assembly,Study on the encapsulation of C₆₀ in metal-coordination-based supramolecular assemblies,which inspires the topic selection and research significance of this thesis.The second chapter is mainly about the synthesis of bis-urea receptors with different terminal substituents and the study on properties of their complexes.The third chapter is mainly about the synthesis of tripodal hexaurea receptors and the interactions of complex with C₆₀.The main experimental contents in chapter 2 and chapter 3 are as follows:1.In the second chapter,the tripodal hexaurea receptor L¹,which is composed of tren-bridging and anthracene substituents,was synthesized.The receptor L¹ with PO₄^3-to form the 1:1 complex（TPA）₃[（PO₄）（L¹）]（2）.The binding of its complex（TBA）₂[（SO₄）（L¹）]（1）to C₆₀ was studied by NMR,fluorescence,UV-vis and DFT calculation.Firstly,NMR showed that there were interactions in CDCl₃ solution,among which,the combination of complex（TBA）₂[（SO₄）（L¹）]（1）and C₆₀0 was also indicated by fluorescence and UV-vis.Job’s plot shows a 2:1 stoichiometry between complex（TBA）₂[（SO₄）（L¹）]（1）and C₆₀.And the binding constants were calculated to be（1.18±0.08）×10³ M^-1 and（6.67±0.43）×10³M^-1 for K_a1 and K_a2 by fluorescence titration.The structure information was studied by DFT calculation,which showed that two complexes and one C₆₀ molecule formed a capsule structure.2.Based on the bi-urea ligand L^a-d,a 3:1 structure can be formed with SO₄^2-and PO₄^3-,which is similar to the coordination structure of the tripodal hexa-urea ligand L¹ with PO₄^3-and SO₄^2-.In the third chapter,the bis-urea ligands L^a-d was synthesized based on anthracene substitution and o-phenyl-bridging.The single crystal structure proved that the bis-urea ligands could coordinate with PO₄^3-to form a 3:1 structure.The structure of its 3:1 is further demonstrated by NMR and MS.The interaction between C₆₀ and sulfate complex of bis-urea ligand was studied.It was found that there was no interaction between sulfate complex of bis-urea ligand and C₆₀ in CDCl₃ solution,revealing the tripodal structure plays an important role during the encapsulation of C₆₀.