The Molecular Binding And Thermodynamic Property Of Three Macrocyclic Hosts With Hydrophobic Cavity

Supramolecular chemistry is one of the important research aspects in chemistry, which is widely used in the fields of catalysis, energy, material, biology, medicine, and so on. Among macrocyclic host molecules, cyclodextrins, cucurbituril, and calixarenes have become some main focuses in supramolecular chemistry. In the thesis, we chose cyclodextrins, cucurbiturils, and calixarenes as the basic research objects to study their recongnition behavior, to construct nanostructural supramolecular polymer as well as manipulate photochirogeneis, which are summarized as follows:1. The general aspect of supramolecular chemistry was described briefly. The new progress and important achievements on supramolecular chiral photochemistry, molecular recognition and assembly of cyclodextrins, cucurbiturils, and calixarenes were reviewed.2. A novel supramolecular ternary polymer mediated by macrocyclic molecules cucurbit[8]uril and cyclodextrin was successfully constructed, based on the cucurbit[8]uril-stabilized charge-transfer interaction and cyclodextrin-adamantane host-guest interaction, which was well characterized by various methods, including diffusion ordered1H NMR spectroscopy, dynamic light scattering, gel permeation chromatography, scanning electron microscopy, atomic force microscopy as well as transmission electron microscopy. In addition, benefiting from the non-covalent nature of supramolecular interactions, we can control the assembly/disassembly of the present supramolecular polymer by adding a competitive guest, such as1-adamantaneamine to the system.3. γ-Cyclodextrin (CD) derivatives with a naphthalene moiety anchored to one or two of the glucose units of the CD were synthesized in order to investigate the effects of flexible and rigid capping upon complexation, as well as Forster resonance energy transfer and photochirogenic behavior of anthracenecarboxylate (AC) moieties. UV-vis, circular dichroism and fluorescence spectral studies revealed that two AC molecules are simultaneously included into the modified γ-CD cavity to form a right-handed screw and also that the naphthalene cap efficiently transfers the singlet energy to AC included in the CD cavity via the FRET mechanism. Interestingly, FRET excitation further enhanced the chemical and optical yields of anti-HH dimer up to36%and35%ee, for which the highly efficient FRET sensitization within the CD cavity, minimizing the "contamination" from the achiral "outside" photoreaction, is responsible. FRET sensitization also enabled us to achieve the catalytic photocyclodimerization of AC with a sub-equivalent amount of chiral supramolecular host.4. By studying the photoreaction of AC in altering excitation wavelengths, we have demonstrated for the first time that the excitation wavelength can be used as a unique, convenient, yet powerful tool for manipulating the relative yield and ee of chiral photoproducts obtained in supramolecular photochirogenesis, circumventing the inherent limitations of ground-state thermodynamics.5. Three guests bearing the ferrocene backbone and varying length of alkyl chains were synthesized. The binding modes, inclusion abilities and thermodynamics between the three guests with p-sulfonatocalix[4]arene (SC4A) and p-sulfonato thiacalix[4]arene (STC4A) at pH2.0and pH7.0were studied, mainly employing the methods of1H NMR,2D ROESY and isothermal titration calorimetry. The results showed that both SC4A and STC4A could form stable complexes with the ferrocene-based guests at pH7.0with binding constants from2.7×104to1.6×105while the binding constants were a little smaller at pH2.0. Furthermore, the binding modes between hosts and guests were quite different at different pH value.