کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10266428 | 459028 | 2005 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Substituent effects on aggregation phenomena in aqueous solution of thiacarbocyanine dyes
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
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چکیده انگلیسی
Visible absorption and fluorescence spectra of seven thiacarbocyanine dyes with varying substituents at 5,5â²- and meso-positions have been studied suggesting J-aggregate formation in aqueous solutions. The molar extinction coefficients of monomers and dimers (ÉM and ÉD), the dimer association constant (KD) and the dimerization enthalpy (ÎHD) were determined studying dye concentration and temperature dependencies of absorption spectra. In 0.01Â mol/dm3 KCl aqueous solutions, J-aggregates were observed due to the association of dimers at a critical dye concentration, which correlated with the KD value. In addition, the aggregation number, the molar extinction coefficient of the J-aggregate (ÉJ) and the J-aggregate association constant (KJ) were quantitatively estimated from a modified Harris-Hobbs equation. The J-aggregates were found to be oligomers composed of 20-80 monomers. KD and ÎHD suggested that substituents at the 5,5â²-position influenced dimer formation and played an important role in aggregates formation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Dyes and Pigments - Volume 66, Issue 1, July 2005, Pages 1-6
Journal: Dyes and Pigments - Volume 66, Issue 1, July 2005, Pages 1-6
نویسندگان
Daisuke Takahashi, Hayato Oda, Tsuyoshi Izumi, Ryo Hirohashi,