Dissertation > Excellent graduate degree dissertation topics show

Molecular Recognition Based on β-cyclodextrin and Chemical Modified β-cyclodextrin as Receptor

Author: WangSuFang
Tutor: WeiYanLi
School: Shanxi University
Course: Analytical Chemistry
Keywords: Naproxen enantiomers β-cyclodextrin (β-CD) Dibromomethane Chiral discrimination Room tempearture phosphorescence (RTP)
CLC: O636.12
Type: Master's thesis
Year: 2011
Downloads: 21
Quote: 0
Read: Download Dissertation

Abstract


Chapter 1:The concept and application of cyclodextrin, modified cyclodextrin were introduced briefly. Summarized the different research technique of chiral discrimination and narrated the orgin and research development of chiral recognition simply.Chapter 2:Naproxen enantiomers possess strong room temperature phosphorescence (RTP) in (3-cyclodextrin (P-CD) system with a small amount of 1,2-dibromoethane (1, 2-DBE) under ambient conditions. The effects of pH, concentration ofβ-CD and 1, 2-DBE on the RTP of naproxen enantiomers have been investigated in detail. Time-resolved RTP spectroscopy shows that both naproxen enantiomers exhibit bi-exponential decay pattern with lifetimes ofτ1= 4.79±0.13 andτ2=1.51±0.096 ms for R-naproxen, andτ1= 6.67±0.15 andτ2= 2.13±0.061 ms for S-naproxen. The lifetime differences between these enantiomers areΔτ1=1.88 andΔτ2r=0.62 ms, indicating that chiral discrimination of naproxen enantiomers can be achieved inβ-CD/1,2-DBE system. Naproxen enantiomers can form stable complexes withβ-CD and 1,2-DBE in stoichiometric ratios of 1:1:2 and 1:1:1 (naproxen:β-CD:1,2-DBE) and the association constants are 3.20×103 M-4 and 2.43×103 M-3 for the S- and R-enantiomers respectively. The chiral discrimination of R-naproxen and S-naproxen is realized via their difference in interaction with the chiral cavity ofβ-CD due to their difference in stereochemical structure. Finally, molecular modeling is performed to determine the chiral recognition on a molecular level and the results are in good agreement with the experimental data.Chapter 3:S-naproxen-modified-β-CD (S-NPX-CDs 1-3) were synthesized by the reactions of (S)-(-)-naproxen with 6-amino-6-deoxy-,3-amino-3-deoxy-, and mono(2-amino-2-deoxy-altro).-β-CDs, respectively. All of them were characterized by HRMS and 1H and 13C NMR spectra. On this basis, the fluorescent and phosphorescent properties of 1 were studied preliminary. The fluorescent and phosphorescent properties of S-naproxen and S-naproxen-modified-β-CD in different medium were also compared, and the results showed that S-naproxen can enter intoβ-CD cavity, so the fluorescence and phosphorescence were enhance.Chapter 4:Firstly, the fluorescence and phosphorescence characteristics of S-NPX-CDs 1-3 were investigated. Then the molecular recognition of S-NPX-CDs 1-3 to small organic objective molecules were explored by RTP method, and the organic small molecules included dibromomethane, bromoform, isodiiodomethane, iodomethane, Carbon Tetrabromide,1,2-dibromomethane, formaldehyde, bromocyclohexane, methane, cyclohexane, formic acid, methanol, ethanol and acetic acid. Among them, only dibromomethane could significantly enhance the RTP signal of S-NPX-CD1, while it had no effect on S-NPX-CDs 2 and 3. Based on this, a RTP method for the determination trace dibromomethane was establised by S-NPX-CDs 1 as the receptor. Then it was applied to determine the content of dibromomethane in coal mine water and the results was in good agreement with the result of GC-MS method. Therefore, a potential RTP sensor of dibromomethane can be developed by S-NPX-CDs 1 as the receptor. Finally, the mechanism was investigated by 1HNMR, dichroism, UV absorption spectra and energy simulatione.

Related Dissertations

  1. Transport Mechanisms of Several Chiral Drugs and Rutin Deca (H-) Sulfonate Sodium in Caco-2 Cell Model,R96
  2. Molecule Recognition Based on the Protein Phosphorescence and Fluorescence,O629.73
  3. The fungicides and raw materials synthesis,O621.25
  4. Study on the Preparation of Ursolic Acid /β- Cyclodextrin Inclusion Complex by Ultrahigh Pressure,TQ461
  5. Efficiency and Influence Factors of Electrodialysis-microbiological Remediation of Oil Contaminated Soil,X53
  6. Studies on Preparing High Temperature-resistant Microencapsulated Sweet Orange Oil by Different Methods,TS225
  7. Theoretical Study of Chiral Discrimination in Hydrogen-bonded Complexes,O641.121
  8. The Preparation and Application Study of β-Cyclodextrin Deodorant on Wool Fabric,TS195.2
  9. Cysteine ??Theoretical Study of the interaction of small molecules and their dimers,O631
  10. Synthesis, Properties and Application of Magnetic Starch,O636.12
  11. Synthesis and Dispersing Performance of Anion Starch,O636.12
  12. study on the Preparation and Application of Cationic Starch with High Degree of Substitution,O636.12
  13. Novel supramolecular reversible system response studies,O636.12
  14. The Controlling of 4αglucanotransferase Cyclization Reaction and the Separation and Application of Large Ring Cyclodextrin,O636.12
  15. Synthesis and Application Properties of Anion Starch,O636.12
  16. Study on the Starch Liquefation Hydrolysis Enhanced by Mechanical Activation,O636.12
  17. The Synthesis and Photochromism Study of the Ester of Starch and AZO-Dyes,O636.12
  18. Oxidation starch graft modification and its current variable performance study,O636.12
  19. Study on the Synthesis and Performance of Polymer β-cyclodextrin Derivatives,O636.12
  20. Synthesis and Characterization of Serials Glycidyl Ether Modified β-Cyclodextrin Derivatives,O636.12

CLC: > Mathematical sciences and chemical > Chemistry > Polymer chemistry ( polymer ) > Natural polymers ( polymer ) > Polymer polysaccharides > Starch, dextrin,glycogen, inulin
© 2012 www.DissertationTopic.Net  Mobile