Study Of Host-Guest Chemistry Of Cucurbituril Homologues And Their Derivatives

1. Interaction of Tetramethylcucurbit[6]uril and Aromatics Derivate PyridineInteractions of the inclusion complexes of tertramethylcucurbit[6]uril (host) and 2-Benpy, 2-Bzpy, 4-Bzpy (guests) have been monitored by ~1H NMR. The thermodynamics constant of complexations and kinetics competition were observed with UV-vis spectrometer. The lowest energy geometry of interaction was calculated by HF/3-21G* basis set after Molecular Dynamics in MM+ force field. The optimization results even show the formation of Host-Guests that is in accordance with the above experiments.2. Molecular Recognition of Amino Acid by CucurbiturilsMolecular recognition of amino acid hydrochlorides (guests) by cucurbit[n]uril (n=7 or 8. hosts) has been studied by 'H NMR. UV-vis spectra titration are employed and the interaction models of 1:1 between guests and Q[7] is obtained. The interaction models between guests and Q[8] is also 1:1 except for the inclusion complex of L-Phenylalanine and Q[8] host. At room temperature, the binding constants (K_a) of TryHCl PheHCl, and TyrHCl for Q7 are 3.73x10~5, 8.15x10~5, and 2.33x10~5 L/mol with nonlinear least square fitting, respectively. A set of fluorescence spectra has been studied for guests and complexes.3. Synthesis of bi-((N-methyI-N'-benzyl)ethylenediamine)Nickel(II) dichloride and studies on the interaction of Cucurbit[n=6~8]urils with Nickel complex guestBi-((N-methyl-N'-benzyl)ethylenediamine)Nickel(II) dichloride was synthesiz ed and characterized by elemental analyses, IR and ~1H NMR techniques. The s elf-assembled structures of cucurbit[n]urils (n=6~8) with the title Ni complex g uest were studied by ~1H NMR and UV-spectra. The experimental results reveal ed clearly that the cucurbit [n=6 or 7] urils can form supramolecule structures with the metal complex guest with 1:2 ratio, and the complex guest can entry or leave the cavity of cucurbit[8]uril without obvious hindrance.