Anion Recognition By Fluorescence Spectrum Based On Cucurbit[n]uril And Syntheses, Characterizations And Properties Of Its Coordination Complexes

Cucurbit[n]uril(n=5-8,Qn) and their derivatives have attracted a lot of scientist' attention.A class of rigid,annular,hollow cavitands with two highly polar carbonyl openings whose interior cavities are large enough to host a variety of molecules, occupy a prominent role in molecular recognition and self-assembly studies, especially be utilized as selective hosts for cationic and neutral guest species.Anion inclusion has also been demonstrated for these unique macrocyclic hosts.The synthesis and the fundamental properties of Qn have been investigated by the outstanding work of the research groups of Fedin,Mock,Kim,and Day,and have led to their applications in many fields.The aim of this dissertation is to investigate the fluorescence spectroscopy of anion recognition based on Qn and their derivative and construct new Qn-Based coordination complexes.This dissertation is mainly composed of three parts:Partâ… :The encapsulation behavior of decamethylcucurbit[5]uril(Me₁₀Q5) towards anion was investigated respectively in the presence of anion acid and anion tetrabutylammonium,revealing that the hydrogen-bonding interaction between proton and the portal of Me₁₀Q5 is the key driven force for the anion into the cavity of metal-free Q5.Partâ…¡:The encapsulation behavior of cucurbit[8]uril towards nitrate,chloride and sulfate ions has been investigated.It has been exhibited to selectively recognize NO₃^-over other anions such as Cl^- and SO₄^2- by a significant quenching of its fluorescence in aqueous solution and in other acid solutions.The stepwise equilibrium constants for formation of the 1:2 complex were obtained.Partâ…¢:One molecular bowl structure based on decamethylcucurbit[5]uril(Me₁₀Q5) and metal ions was obtained,namely,[Hg(C₃₀H₅₀N₂₀O₁₀)Cl₂(H₂O)]HgCl₂(H₂O)₅(1), one complexes based on cucurbit[6]uril(Q6) and metal ions,namely,(C₃₆H₃₆N₂₄O₁₂) Hg₂Cl₇ Na₃(H₂O)₁₁(2) also was prepared.A chloride ion was encapsulated by decamethylcucurbit[5]uril in compound(1),but in compound(2) there is no chloride ion encapsulated in cucurbit[6]uril.On the basis of compound(2),we get compound (C₃₆H₃₆N₂₄O₁₂)₂([Bu₄N]⁺)₅(HgCl₄^2-)₄(H₃O⁺)₃(H₂O)₁₁(3),which encapsulates single chain of tetrabutylammonium cation,not chloride ion.These indicate that size matching and electrostatic interaction make important roles in encapsulation of chloride ion.