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Effects of Self‐coiling of Organic Molecules on Intramolecular Exciplex Formation and Fluorescence Quenching in DX‐H 2 O Solvent System
Author(s) -
Chen YingQi,
Li ZhanTing,
Wang XiaoZhong,
Jiang XiKui,
Shi JiLiang,
Shi Min
Publication year - 2002
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.20020200209
Subject(s) - chemistry , chromophore , excimer , intramolecular force , carbazole , photochemistry , moiety , acceptor , fluorescence , molecule , intermolecular force , quenching (fluorescence) , excited state , stereochemistry , organic chemistry , physics , quantum mechanics , nuclear physics , condensed matter physics
Effects of self‐coiling of organic molecules on intramolecular exciplex formation of compound I, in which the carbazole chromophore and terephthalic acid methylester acceptor group are linked by one (CH 2 ) 10 chain, and the decrease of the fluorescence intensities of compounds II, III, and IV, in which the carbazole chromophore and 3,5‐dinitrobenzoate are connected by one aliphatic chain of (CH 2 ) 10 (II), (CH 2 ) 12 (III), or (CH 2 ) 4 (IV), have been studied in the dioxane(DX)‐H 2 O binary system. The results show that self‐coiling of organic molecules in DX‐H 2 O facilitates intramolecular exciplex formation of I and induces the decrease of fluorescence intensities of II, because of the proximity effect brought about by self‐coiling of organic molecules under hydrophobic‐lipophilic interaction (HLI) between the excited carbazole chromophore and the acceptor. Since the similar effects are observed even when the concentrations of the probes are less than their CAgCs (critical aggregate concentrations) in the DX‐H 2 O mixture with the same ϕ values, formation of the intermolecular exciplex has been excluded. The effects are found to be strongly depended on ϕ values, indicating that they are mainly driven by HLI. The properties of the acceptors can also affect the intramolecular exciplex formation. With terephthalic add methylester moiety as the acceptor, the carbazole chromophore exhibits the fluorescence spectra of the exciplex, while with 3,5‐dinitrobenzoate moiety as the acceptor, only the fluorescence spectra of excited carbazolyl chromophore are observed.