Using Luminescence To Show Intramolecular and Intermolecular Hydrogen Bonding: An Activity for General Chemistry or Physical Chemistry

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• 作者：Cheng-Wei Ni ; Gu-Ying Lin ; Ting-Yi Wang ; Mei-Lin Ho
• 刊名：Journal of Chemical Education
• 出版年：2015
• 出版时间：February 10, 2015
• 年：2015
• 卷：92
• 期：2
• 页码：322-327
• 全文大小：332K
• ISSN：1938-1328

文摘

A hands-on activity for students in general chemistry and physical chemistry courses has been designed to facilitate study of intramolecular (IntraHB) and intermolecular (InterHB) hydrogen bonding in biomolecules using luminescence. 3-Hydroxyflavone (3-HF), the backbone of all flavonols, is a promising model molecule, for it possesses an excited-state intramolecular proton transfer (ESIPT) effect that can serve as a fluorescent probe for studying many biological systems. The luminescence of 3-HF has one or two bands, whose intensities are dependent on temperature and solvent. In this activity, molecular models are used to illustrate hydrogen bonding of 3-HF in the ground state in two solvents, ethanol and hexane. Then students perform an activity to enable them to observe the luminescence of 3-HF in ethanol and in hexane, at room temperature and at 77 K, respectively, followed by discussion of the luminescence of 3-HF in ordinary filter paper. The project allows students to relate the idea of hydrogen bonding in the ground state to a luminescence color change in the excited state through a naked-eye experiment.