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Study on the Molecular Recognition of Cucurbiturils for Their Applications in Chromatography and Others

Author: HeXiaoYing
Tutor: LiLaiSheng
School: Nanchang University
Course: Analytical Chemistry
Keywords: The gourd [ 5 8 ] urea Gas chromatographic stationary phases Fluorescence Spectrometry UV-visible spectroscopy Molecular Recognition Zhi.A BSA Purine Direct Dyes
CLC: O621.25
Type: Master's thesis
Year: 2011
Downloads: 85
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Abstract

Molecular recognition is the core of the supramolecular systems, but also formed the basis of supramolecular structure. It refers to the process through the space between the subject and object matching the intermolecular interaction, optionally combined with each other and produce a specific function. There are huge potential and broad prospects for application of molecular recognition in separation materials, drug delivery, and environmental pollution control, increasingly attaches great importance to analytical chemists, medicinal chemists and environmental chemist. The port is surrounded by a number of carbonyl. The experiments confirmed CUCURBITURIL showed strong molecular recognition ability of many organic cations and neutral molecules object. This thesis gourd [7] urea to do with the body, for the first time prepared a gourd [7] urea gas chromatography stationary phases, representing a systematic study of the stationary phase chromatographic performance. Fluorescence spectrometry and UV-visible spectrum as a means to systematically study the gourd [7] urea and bovine serum albumin (BSA), purine, dye interactions lay the theoretical foundation and its application in related fields. The main contents are as follows: 1, a more comprehensive overview of a the Cucurbit family's structure characteristics, synthetic methods; emphasis summarized role of molecular recognition CUCURBITURIL current situation and future in analytical chemistry prospects. The topic of this paper as the basis and the starting point of the experimental design. 2 currently about Cucurbituril is the synthesis and separation and purification of less. In this thesis, the reference on the basis of previous work, using paraformaldehyde in place of 40% formaldehyde solution and the acid points in the first water to simplify the preparation of the separation process, Cucurbit [7] urea production, while reducing the amount of hydrochloric acid, protecting the environment, reduce production costs and provide the raw materials for the preparation the Cucurbit Gas stationary phase and research Cucurbituril, molecular recognition role. 3, for the first time prepared a gourd [7] of urea gas chromatography fill column (3.2 mm × 2.1m), different solute probe, evaluate the performance of new stationary phase chromatography, and chromatographic separation mechanism. The results showed that: CB [7] fixed relative to aromatic hydrocarbons, halogenated hydrocarbons, alcohols, ketones, esters, silicones, and other extensive separation object display a high selectivity of separation, for example, difficult to separate the alcohol position isobutyl isomer also have a good separation capacity, particularly at high column temperature rapid separation of high boiling esters and silicone compound (lt; 7min), when high heating rate to reach 150 ° C min-1 still remain stable baseline. This is due to a high degree of stability and a variety of supramolecular structure of CUCURBITURIL role, including the inclusion of gaseous solute role. Therefore, CB [7] stationary phase is more suitable for the separation of high boiling point compounds, is a good GC stationary phase. 4, gourd [7] urea in addition to doing the separating material, but also a new type of drug carrier. Better water-soluble CB [7] using fluorescence spectroscopy to study the interaction with bovine serum albumin (BSA), has not been reported. It was found that the physiological pH 7.4, the fluorescence intensity of BSA inside source with the CB [7] concentration increases significantly lower fluorescence peaks redshift and quenching constant with increasing temperature and decreased gradually. Stern-Volmer equation and Lineweaver-Burk double reciprocal equation processing of experimental data obtained under different temperatures the reaction binding constants, number of binding sites and related thermodynamic parameters. Measured at 298K of CB [7] with BSA apparent binding constant (KA) for 2.3367 × 105 Lmol-1, the number of binding sites for 1.078. Based on thermodynamic parameters hydrophobic interactions and electrostatic interactions both the major synergistic interactions between them. Hydrophobic effects from the hydrophobic cavity of the cucurbituril Zhi.A BSA portion of the amino acid residues, together with electrostatic interactions to maintain the stability of the CB [7]-BSA. The synchronous fluorescence study found that CB [7] did not cause changes in the conformation of BSA, provides useful information for CUCURBITURIL applications in drug delivery and life sciences. 5, by fluorescence spectroscopy of CB [7] mercaptopurine (6-MP) and adenine (ADP) Zhi.A time, pH and temperature on the fluorescence intensity and Zhi.A using Benesi -Hildebrand equation calculated mercaptopurine and adenine with CB [7] inclusion constant. The experiments show that: acidity have a significant impact on the inclusion of the system. Mercaptopurine at pH = 8.0 and adenine in the pH = 2.0, respectively, having a stable and optimum excitation and emission wavelengths, with CB [7] the increasing concentration of the fluorescence intensity of the system has significantly enhanced Zhi.A rapidly (less than 5min). Experimental CB [7] with mercaptopurine and adeno neopterin package knot ratios are 1:1, and the inclusion constant at 298K 3.6797 × 102Lmol-1 and 2.2033 × 102 L mol-1, respectively. Through changes in the thermodynamic parameters, to explore the main force to maintain the stability of the inclusion complexes. CB [7] the Cucurbit family the most water-soluble host molecules, great potential as a safe and low toxicity of the drug carrier. 6, the interaction of UV-visible spectrometry CB [7] with direct scarlet, direct red, direct acid Claret three commonly used water-soluble direct dyes. It was found that with CB [7] the increasing concentration of a significant reduction in the absorbance of the three dyes are suction point, and investigated the concentration of the molecules of the main body, the pH of the buffer, temperature, organic solvents, surfactants, etc. Factors spectral changes. The results showed that the CB [7] respectively with the three dyes form stable complexes, the formation of such complexes and their role on the part of the inclusion of the group structure of dyes related. Use equimolar ratio method and Job determine 1:1 inclusion complexes are formed. Measured thermodynamic parameters for inclusion shows: their inclusion reactions are exothermic process, which may be the main guest molecules between hydrophobic interactions and hydrogen bonding interactions sake.

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