کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5377326 1389386 2006 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Intramolecular charge transfer effects on 3-aminobenzoic acid
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Intramolecular charge transfer effects on 3-aminobenzoic acid
چکیده انگلیسی
Effect of solvents, buffer solutions of different pH and β-cyclodextrin on the absorption and fluorescence spectra of 3-aminobenzoic acid (3ABA) have been investigated. The solid inclusion complex of 3ABA with β-CD is discussed by UV-Vis, fluorimetry, semiempirical quantum calculations (AM1), FT-IR, 1H NMR and Scanning Electron Microscope (SEM). The thermodynamic parameters (ΔH, ΔG and ΔS) of the inclusion process are also determined. The experimental results indicated that the inclusion processes is an exothermic and spontaneous. The large Stokes shift emission in solvents with 3ABA are correlated with different solvent polarity scales suggest that, 3ABA molecule is more polar in the S1 state. Solvent, β-CD studies and excited state dipole moment values confirms that the presence of intramolecular charge transfer (ICT) in 3ABA. Acidity constants for different prototropic equilibria of 3ABA in the S0 and S1 states are calculated. β-Cyclodextrin studies shows that 3ABA forms a 1:1 inclusion complex with β-CD. β-CD studies suggest COOH group present in non-polar part and amino group present in hydrophilic part of the β-CD cavity. A mechanism is proposed to explain the inclusion process.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Physics - Volume 322, Issue 3, 20 March 2006, Pages 311-322
نویسندگان
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