An Evidence for the Chiral Discrimination of Naproxen Enantiomers: A Combined Experimental and Theoretical Study

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• 作者：Yanli Wei ; Sufang Wang ; Jianbin Chao ; Songbai Wang ; Chuan Dong ; Shaomin Shuang ; Man Chin Paau ; Martin M. F. Choi
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：March 17, 2011
• 年：2011
• 卷：115
• 期：10
• 页码：4033-4040
• 全文大小：958K
• 年卷期：v.115,no.10(March 17, 2011)
• ISSN：1932-7455

文摘

Naproxen enantiomers possess strong room temperature phosphorescence (RTP) in 尾-cyclodextrin (尾-CD) system with a small amount of 1,2-dibromoethane (1,2-DBE) under ambient conditions. The effects of pH, concentration of 尾-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 biexponential decay pattern with lifetimes of 蟿₁ = 4.79 卤 0.13 and 蟿₂ = 1.51 卤 0.096 ms for R-naproxen and 蟿₁ = 6.67 卤 0.15 and 蟿₂ = 2.13 卤 0.061 ms for S-naproxen. The lifetime differences between these enantiomers are 螖蟿₁ = 1.88 and 螖蟿₂ = 0.62 ms, indicating that chiral discrimination of naproxen enantiomers can be achieved in 尾-CD/1,2-DBE system. Naproxen enantiomers can form stable complexes with 尾-CD and 1,2-DBE in stoichiometric ratios of 1:1:2 and 1:1:1 (naproxen:尾-CD:1,2-DBE), and the association constants are 3.20 脳 10³ M^鈭? and 2.43 脳 10³ M^鈭? 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 of 尾-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.