Abstract
Two p-nitrophenol modified β-CDs (1,2) were synthesized in order to assess colour changes induced by host-guest complexation as well as to investigate their conformations and binding properties as colour changeable indicators for the presence of organic molecules in pH neutral aqueous solutions. Host 3, which has an α-CD in place of the β-CD of 1, was also synthesized for comparison. The induced circular dichroism spectra of 1-3 suggest that thep-nitrophenol unit of 1 and 3 is not completely included in their CD cavities and that of 2 is fully included in its β-CD cavity. The spectra of 1-3 in the presence of guest supported these results, slightly enhancing the absolute intensities for 1 and 3 and decreasing the intensity for 2 The guest-induced conformation changes of 1-3 caused the colour to change from yellow to colourless, which is associated with the conversion of the appending moiety from phenolate anion to neutral phenol species at pH 5.10 for 1 and 3 and at pH 6.50 for 2. The binding constants of 1 were markedly larger than those for 2, reflecting that the p-nitrophenol moiety of 1 acts as an effective hydrophobic cap while that of 2 acts as an intramolecular inhibitor upon guest accommodation. These results demonstrate that various colour changeable indicators for molecules which work under neutral conditions may be constructed on the basis of the appropriate design of the appending part in dye-modified cyclodextrins.
| Original language | English |
|---|---|
| Pages (from-to) | 1705-1710 |
| Number of pages | 6 |
| Journal | Journal of the Chemical Society. Perkin Transactions 2 |
| Issue number | 9 |
| Publication status | Published - 1997 Sep |
| Externally published | Yes |
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ASJC Scopus subject areas
- Chemistry(all)
Cite this
Guest-induced colour changes and molecule-sensing abilities of p-nitrophenol-modified cyclodextrins. / Matsushita, Akiko; Kuwabara, Tetsuo; Nakamura, Asao; Ikeda, Hiroshi; Ueno, Akihiko.
In: Journal of the Chemical Society. Perkin Transactions 2, No. 9, 09.1997, p. 1705-1710.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Guest-induced colour changes and molecule-sensing abilities of p-nitrophenol-modified cyclodextrins
AU - Matsushita, Akiko
AU - Kuwabara, Tetsuo
AU - Nakamura, Asao
AU - Ikeda, Hiroshi
AU - Ueno, Akihiko
PY - 1997/9
Y1 - 1997/9
N2 - Two p-nitrophenol modified β-CDs (1,2) were synthesized in order to assess colour changes induced by host-guest complexation as well as to investigate their conformations and binding properties as colour changeable indicators for the presence of organic molecules in pH neutral aqueous solutions. Host 3, which has an α-CD in place of the β-CD of 1, was also synthesized for comparison. The induced circular dichroism spectra of 1-3 suggest that thep-nitrophenol unit of 1 and 3 is not completely included in their CD cavities and that of 2 is fully included in its β-CD cavity. The spectra of 1-3 in the presence of guest supported these results, slightly enhancing the absolute intensities for 1 and 3 and decreasing the intensity for 2 The guest-induced conformation changes of 1-3 caused the colour to change from yellow to colourless, which is associated with the conversion of the appending moiety from phenolate anion to neutral phenol species at pH 5.10 for 1 and 3 and at pH 6.50 for 2. The binding constants of 1 were markedly larger than those for 2, reflecting that the p-nitrophenol moiety of 1 acts as an effective hydrophobic cap while that of 2 acts as an intramolecular inhibitor upon guest accommodation. These results demonstrate that various colour changeable indicators for molecules which work under neutral conditions may be constructed on the basis of the appropriate design of the appending part in dye-modified cyclodextrins.
AB - Two p-nitrophenol modified β-CDs (1,2) were synthesized in order to assess colour changes induced by host-guest complexation as well as to investigate their conformations and binding properties as colour changeable indicators for the presence of organic molecules in pH neutral aqueous solutions. Host 3, which has an α-CD in place of the β-CD of 1, was also synthesized for comparison. The induced circular dichroism spectra of 1-3 suggest that thep-nitrophenol unit of 1 and 3 is not completely included in their CD cavities and that of 2 is fully included in its β-CD cavity. The spectra of 1-3 in the presence of guest supported these results, slightly enhancing the absolute intensities for 1 and 3 and decreasing the intensity for 2 The guest-induced conformation changes of 1-3 caused the colour to change from yellow to colourless, which is associated with the conversion of the appending moiety from phenolate anion to neutral phenol species at pH 5.10 for 1 and 3 and at pH 6.50 for 2. The binding constants of 1 were markedly larger than those for 2, reflecting that the p-nitrophenol moiety of 1 acts as an effective hydrophobic cap while that of 2 acts as an intramolecular inhibitor upon guest accommodation. These results demonstrate that various colour changeable indicators for molecules which work under neutral conditions may be constructed on the basis of the appropriate design of the appending part in dye-modified cyclodextrins.
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UR - http://www.scopus.com/inward/citedby.url?scp=0001925690&partnerID=8YFLogxK
M3 - Article
SP - 1705
EP - 1710
JO - Journal of the Chemical Society, Perkin Transactions 2
JF - Journal of the Chemical Society, Perkin Transactions 2
SN - 1470-1820
IS - 9
ER -