Conformational Analysis of Quinine and Its Pseudo Enantiomer Quinidine: A Combined Jet-Cooled Spectroscopy and Vibrational Circular Dichroism Study
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- 作者：Ananya Sen ; Aude Bouchet ; Valeria Lep猫re ; Katia Le Barbu-Debus ; D. Scuderi ; F. Piuzzi ; A. Zehnacker-Rentien
- 刊名：The Journal of Physical Chemistry A
- 出版年：2012
- 出版时间：August 16, 2012
- 年：2012
- 卷：116
- 期：32
- 页码：8334-8344
- 全文大小：471K
- 年卷期：v.116,no.32(August 16, 2012)
- ISSN：1520-5215
文摘
Laser-desorbed quinine and quinidine have been studied in the gas phase by combining supersonic expansion with laser spectroscopy, namely, laser-induced fluorescence (LIF), resonance-enhanced multiphoton ionization (REMPI), and IR-UV double resonance experiments. Density funtional theory (DFT) calculations have been done in conjunction with the experimental work. The first electronic transition of quinine and quinidine is of 蟺鈥撓€* nature, and the studied molecules weakly fluoresce in the gas phase, in contrast to what was observed in solution (Qin, W. W.; et al. J. Phys. Chem. C2009, 113, 11790). The two pseudo enantiomers quinine and quinidine show limited differences in the gas phase; their main conformation is of open type as it is in solution. However, vibrational circular dichroism (VCD) experiments in solution show that additional conformers exist in condensed phase for quinidine, which are not observed for quinine. This difference in behavior between the two pseudo enantiomers is discussed.