Study On The Application Of Cyclodextrin-induced Room Temperature Phosphorescence In Chiral Discrimination

Chapter 1 The researching background of non-deoxygenated room temperature phosphorescence (RTP) is briefly introduced. And cyclodextrin-induced RTP in the presence of oxygen is reviewed in detail. Methods of chiral recognition as well as some common chiral selectors are summarized. Finally the scope of thesis is introduced.Chapter 2 Upon addition of small amount of bromocyclohexane (BrCH), cinchonine (CN) and cinchonidine (CD) display strong room temperature phosphorescence (RTP) inγ-cyclodextrin(y-CD) solution without deoxygenation. And the RTP intensity of CN is about four times larger than that of CD. The associated phosphorescence decay curves can be best fitted to biexponential patterns and quite different RTP lifetimes were obtained for CN (7.384 and 1.213 ms) and CD (5.443 and 0.064 ms), indicating a distinct chiral discrimination ofγ-CD toward this pair of pseudo-enantiomers.Chapter 3 Strong room temperature phosphorescence (RTP) of camphorquinone (CQ) is synergistically induced by a-cyclodextrin (a-CD) and 1,2-dibromoethane (1,2-DBE) without removal of oxygen dissolved in the solution because of the formation of ternary complex of a-CD, CQ, and 1,2-DBE with 1:2:2 stoichiometry. Both (R)-CQ and (S)-CQ exhibit single exponential phosphorescence decay with lifetimes of (0.274±0.014) ms and (0.639±0.021) ms for (R)-CQ and (S)-CQ, respectively. The relatively large RTP lifetime difference observed for (R)-CQ and (S)-CQ enables easy spectroscopic discrimination between this pair of enantiomers based on simple time-resolved detection. In addition, the RTP intensity can be correlated linearly with the enantiomeric composition of CQ. Therefore the proposed method enables the determination of the enantiomeric composition of a CQ mixture.'HNMR as well as 2D-NMR spectroscopic studies show that the CQ molecule is included in the hydrophobic cavity at the wider end while 1,2-DBE molecule is introduced within a-CD through the narrower end of the cavity.Chapter4 In the presence of small amount of 1-iodobutane (IBu),β-cyclodextrin can induce naproxen (Nap) to emit strong room temperature phosphorescence without deoxygenation. And the RTP intensity of (R)-Naproxen is larger than that of (S)-Naproxen. Additionally, the RTP intensity can be correlated linearly with the enantiomeric composition of Nap. Therefore the proposed method enables the determination of the enantiomeric composition of a Nap mixture. Both (R)-Naproxen and (S)-Naproxen exhibit single exponential phosphorescence decay with lifetimes of 2.535±0.056 ms and 1.798±0.076 ms for (R)-Naproxen and for (S)-Naproxen, respectively. The large lifetime difference(34.02%) can be used for the chiral discrimination of (R)-Nap and (S)-Nap enantiomers.