Two-Dimensional Synchronous Correlation Spectroscopy for Probing Fluorescence Energy Transfer
HUANG Kun1, CHEN Jing1, LIU Shao-xuan1, GAO Xiu-xiang1, PAN Qing-hua1, ZHANG Cheng-feng1, 2, LIU Yu-hai1, 2, XIA Jin-ming1, 3, QI Jian1, XU Yi-zhuang1*, WU Jin-guang1
1. College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China 2. Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China 3. Liaoning University of Traditional Chinese Medicine, Shenyang 110032, China
Abstract：In the present paper, the authors developed a new approach by constructing two-dimensional (2D) UV-Vis/fluorescence heterogeneous synchronous spectrum based on the orthogonal sample design scheme (OSD) developed in our previous works to characterize energy transfer among different lanthanide ions during the luminescence process. The authors use the EuCl3-NdCl3 system as an example. The preliminary experimental results on the 2D synchronous spectra of EuCl3-NdCl3 mixture solutions have demonstrated that cross peaks can be observed among the UV-Vis absorption bands from Nd3+ and fluorescence emission bands from Eu3+. The cross peaks in the 2D synchronous spectra of EuCl3-NdCl3 mixture solutions manifested the interaction between the fluorescence emission from Eu3+ and UV-Vis absorbance from Nd3+, and therefore gives out experimental evidences for the occurrence of energy transfer between Eu3+ and Nd3+ ions. The cross peaks are not from the interaction between the solvent, water, and the solute, Eu3+ or Nd3+ ions. Mathematical analysis performed on 2D synchronous spectra using variable concentration as an external perturbation shows that the orthogonal sample design scheme is indispensable in removing the interfering cross peaks in 2D synchronous spectra. In fact, if the authors detect, respectively, the fluorescence emission spectra of pure Eu3+ solutions and the UV-Vis absorbance spectra of pure Nd3+ solutions, then use these spectra data to construct a series of synthesized spectra of an assumed mixture solution in which Eu3+ and Nd3+ are not mixed together, because Eu3+ and Nd3+ ions are spatially separated, there are no intermolecular interactions that should have occurred. Therefore, there are no cross-peaks that can be observed in the comparative 2D synchronous spectra. The cross peaks in 2D synchronous correlation spectra gives out a new approach to characterizing energy transfer among different lanthanide ions during the luminescence process.
Key words：Orthogonal;2D synchronous spectra;Cross peak;Interaction;Energy transfer
[1] Telor N J. Molecular Photochemistry. United States: Columbia Uni. Press，1978. 331. [2] LI Rui, DAI Ben-cai, ZHAO Yong-de, et al(李 锐, 代本才, 赵永德, 等). Spectroscopy and Spectral Analysis (光谱学与光谱分析), 2009, 29(1): 240. [3] Thomas P, Ken S, Louise B, et al. Biochemistry, 1999, 38(40): 13026. [4] Susumu A, Michael L B, Chan S O, et al. Chem. Commun., 2001, 18: 1836. [5] Kristian K J, Lene M, Thue W S. Biochemistry, 2001, 40: 938. [6] Chang Q, Jeffrey S, Joseph R L, et al. Anal. Biochem., 1995, 232: 92. [7] Liu S X, Fang Y, Hu D D, et al. J. Appl. Polym. Sci., 2001, 82: 620. [8] XU Jin-gou, WANG Zun-ben(许金钩，王尊本). Fluorescence Analysis(荧光分析法). Beijing: Science Press(北京: 科学出版社)，2006. 18. [9] Noda I, Ozaki Y. Two-Dimensional Correlation Spectroscopy. UK: Wiley, Chichester, 2004. [10] Noda I. J. Am. Chem. Soc., 1989, 111: 8116. [11] Noda I. Applied Spectroscopy, 1990, 44(4): 550. [12] Noda I, Dowrey A E, Marcott C. Applied Spectroscopy, 1993, 47(9): 1317. [13] Noda I. Applied Spectroscopy, 1993, 47(9): 1329. [14] Slobodan S, Ozaki Y. Anal. Chem., 2001, 73: 2294. [15] WU Qiang, WANG Jing(吴 强，王 静). Chinese J. Chemistry(化学通报), 2000, 63(8): 45. [16] Zheng Junrong, Kyungwon K, Xie Jia, et al. Science, 2006, 313: 1951. [17] YU Jing, WU Pei-yi(余 婧, 武培怡). Progress in Chemistry(化学进展), 2006, 18(12): 1691. [18] PENG Yun, SHEN Yi, WU Pei-yi，et al(彭 云，沈 怡，武培怡, 等). Chinese Journal of Analytical Chemistry(分析化学), 2005, 33(10): 1499. [19] Noda I. Journal of Molecular Structure, 2008, 883-884: 2. [20] Qi Jian, Li Hui-zhen, Huang Kun, et al. Applied Spectroscopy, 2007, 61: 1359. [21] Chen Jing, Zhang Cheng-feng, Li Hui-zhen et al. Journal of Molecular Structure, 2008, 883-884: 129. [22] Qi Jian, Huang Kun, Gao Xiu-xiang, et al. Journal of Molecular Structure, 2008, 883-884: 116. [23] Liu Yu-hai, Zhang Cheng-feng, Liu Shao-xuan, et al. Journal of Molecular Structure, 2008, 883-884: 124. [24] Noda I. Applied Spectroscopy, 2000, 54(7): 994.
