Effects of Hydrogen-bonding Interaction and Polarity on Emission Spectrum of Naphthalene-Triethylamine in Mixed Solvent

作     者：Yoshimi Sueishi Shunzo Yamamoto 

作者机构：Graduate School of Natural Science and Technology Okayama University 3-1-1 Tsushima-Naka Okayama 700-8530 JapanGraduate School of Natural Science and Technology Okayama University 3-1-1 Tsushima-Naka Okayama 700-8530 Japan 

出 版 物：《Chemical Research in Chinese Universities》 (高等学校化学研究（英文版）)

年 卷 期：2004年第20卷第5期

页      面：606-611页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070303[理学-有机化学] 0703[理学-化学] 

主　　题：Naphthalene-triethylamine Fluorescence spectrum Solvent effect Solvent polarity Hydrogen-bonding interaction. 

摘      要：The effects of the protic and aprotic polar solvents on the emission spectrum of the naphthalene-triethyl-amine system in THF were studied under conditions of steady-state illumination. The fluorescence spectrum of the naphthalene-triethylamine system consists of two emission bands, the fluorescence band of naphthalene(band A, 329 nm) and the emission band of the exciplex(band B, 468 nm). The intensities of both the emission bands decrease with increasing the solvent polarity. The intensity of band B also decreases due to the hydrogen-bonding interaction between triethylamine and protic solvent, while that of band A increases. It is thus suggested that the quenching of naphthalene fluorescence by triethylamine in THF occurs through the charge transfer and electron transfer reactions. The spectral changes upon the increase of solvent polarity can be explained by the dependences of the equilibrium constant between exciplex and ion-pair and the rate constant for the electron transfer reaction from triethylamine to the excited naphthalene on the relative permittivity of solvent. It is shown that the formation of intermolecular hydrogen-bonding between triethylamine and protic solvent suppresses the quenching reaction by the decrease in free amine. Acetonitrile has only a polar effect and trichloroacetic acid only a hydrogen-bonding(or protonation) effect, while alcohols have both the effects. The effects of alcohols could be separated into the effects of solvent polarity and intermolecular hydrogen-bonding interaction quantitatively.