Cooperative dissociation of J-aggregates into monomers in the 2-isobutoxyethanol/water binary solvent with the lower critical solution temperature
| Autor: | Tomoyuki Yatsuhashi, Mio Harada, Shunsuke Yamamoto, Kenji Sakota |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
010304 chemical physics
Absorption spectroscopy Supramolecular chemistry General Physics and Astronomy 010402 general chemistry 01 natural sciences Lower critical solution temperature Dissociation (chemistry) 0104 chemical sciences Solvent chemistry.chemical_compound Perchlorate Monomer chemistry 0103 physical sciences Physical chemistry Physical and Theoretical Chemistry J-aggregate |
| Zdroj: | Chemical Physics. 536:110817 |
| ISSN: | 0301-0104 |
| Popis: | J-aggregates are supramolecular assemblies with characteristic optical properties originating from their excitonic interactions and have applications in fluorescence biosensing and artificial light-harvesting systems. Herein, we investigated the formation and dissociation of the J-aggregates of 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiIC18(3)) in 2-isobutoxyethanol (iBE)/water (W) binary solvents with the lower critical solution temperature (LCST). We found that DiIC18(3) forms J-aggregates in iBE/W binary solvents with compositions of 12/88–17/83% (v/v). By measuring the temperature dependence of the absorption spectra, we found that the J-aggregates dissociate into monomers cooperatively before the iBE/W binary solvents show the liquid–liquid phase separation. The hydrophobicity of the iBE/W binary solvents was evaluated by measuring the fluorescence spectra of 1-Anilinonaphtharene-8-sulfonic acid (1,8-ANS), whose fluorescence peak wavelength reflects the hydrophobicity of the solvents. The J-aggregates were found to dissociate cooperatively when the iBE/W binary solvents reached a constant hydrophobicity, although the composition of the iBE/W binary solvents was different. The J-aggregates precipitated without dissociation in binary solvents without the LCST. We propose that concentration fluctuation of iBE/W binary solvents promotes the cooperative dissociation of the DiIC18(3) J-aggregates. |
| Databáze: | OpenAIRE |
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