Abstract
The helical structure is one of key structural components for both biological systems and artificial chiral systems. So far, we have succeeded in fabricating "tight" insulated molecular wires consisting of a triple-stranded cohelical structure formed through supramolecular wrapping of synthetic polymers by a helix-forming polysaccharide (schizophyllan). Herein, we have designed a new modified polysaccharide (Cur-oeg) to form a "loose" macromolecular complex with a conjugated polymer (CP) that allows structural changes in response to external stimuli. Cur-oeg forms a helical complex with an achiral cationic polythiophene (PT1), and the effective conjugation length is changed by temperature, showing a large absorption peak shift from 403 to 482 nm between 85 and 5 °C. According to the change in the conjugation system, the fluorescence and the induced circular dichroism show the continuous spectral shifts under temperature control. The color changes in the absorption and the fluorescence are detectable with observation by the naked eye and are reversibly controlled under thermal cycles, indicating that this system has the function of a "molecular thermometer". It is shown that the induced thermoresponsiveness is associated with structural rearrangement of the helical conformation of PT1 in the complex. Moreover, another unique responsiveness is discovered for the film state: that is, the film color is varied when it is exposed to the vapor of water or methanol (vaporchromism), resulting from the structural change of PT1 occurring even in the film state. These flexible molecular motions in both the solution state and the film state can be applicable to the design of CP-based smart sensors, polarized materials, switching devices, etc.
| Original language | English |
|---|---|
| Pages (from-to) | 13928-13935 |
| Number of pages | 8 |
| Journal | Journal of the American Chemical Society |
| Volume | 132 |
| Issue number | 39 |
| DOIs | |
| Publication status | Published - Oct 6 2010 |
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All Science Journal Classification (ASJC) codes
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
Cite this
Thermo- and solvent-responsive polymer complex created from supramolecular complexation between a helix-forming polysaccharide and a cationic polythiophene. / Shiraki, Tomohiro; Dawn, Arnab; Tsuchiya, Youichi; Shinkai, Seiji.
In: Journal of the American Chemical Society, Vol. 132, No. 39, 06.10.2010, p. 13928-13935.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Thermo- and solvent-responsive polymer complex created from supramolecular complexation between a helix-forming polysaccharide and a cationic polythiophene
AU - Shiraki, Tomohiro
AU - Dawn, Arnab
AU - Tsuchiya, Youichi
AU - Shinkai, Seiji
PY - 2010/10/6
Y1 - 2010/10/6
N2 - The helical structure is one of key structural components for both biological systems and artificial chiral systems. So far, we have succeeded in fabricating "tight" insulated molecular wires consisting of a triple-stranded cohelical structure formed through supramolecular wrapping of synthetic polymers by a helix-forming polysaccharide (schizophyllan). Herein, we have designed a new modified polysaccharide (Cur-oeg) to form a "loose" macromolecular complex with a conjugated polymer (CP) that allows structural changes in response to external stimuli. Cur-oeg forms a helical complex with an achiral cationic polythiophene (PT1), and the effective conjugation length is changed by temperature, showing a large absorption peak shift from 403 to 482 nm between 85 and 5 °C. According to the change in the conjugation system, the fluorescence and the induced circular dichroism show the continuous spectral shifts under temperature control. The color changes in the absorption and the fluorescence are detectable with observation by the naked eye and are reversibly controlled under thermal cycles, indicating that this system has the function of a "molecular thermometer". It is shown that the induced thermoresponsiveness is associated with structural rearrangement of the helical conformation of PT1 in the complex. Moreover, another unique responsiveness is discovered for the film state: that is, the film color is varied when it is exposed to the vapor of water or methanol (vaporchromism), resulting from the structural change of PT1 occurring even in the film state. These flexible molecular motions in both the solution state and the film state can be applicable to the design of CP-based smart sensors, polarized materials, switching devices, etc.
AB - The helical structure is one of key structural components for both biological systems and artificial chiral systems. So far, we have succeeded in fabricating "tight" insulated molecular wires consisting of a triple-stranded cohelical structure formed through supramolecular wrapping of synthetic polymers by a helix-forming polysaccharide (schizophyllan). Herein, we have designed a new modified polysaccharide (Cur-oeg) to form a "loose" macromolecular complex with a conjugated polymer (CP) that allows structural changes in response to external stimuli. Cur-oeg forms a helical complex with an achiral cationic polythiophene (PT1), and the effective conjugation length is changed by temperature, showing a large absorption peak shift from 403 to 482 nm between 85 and 5 °C. According to the change in the conjugation system, the fluorescence and the induced circular dichroism show the continuous spectral shifts under temperature control. The color changes in the absorption and the fluorescence are detectable with observation by the naked eye and are reversibly controlled under thermal cycles, indicating that this system has the function of a "molecular thermometer". It is shown that the induced thermoresponsiveness is associated with structural rearrangement of the helical conformation of PT1 in the complex. Moreover, another unique responsiveness is discovered for the film state: that is, the film color is varied when it is exposed to the vapor of water or methanol (vaporchromism), resulting from the structural change of PT1 occurring even in the film state. These flexible molecular motions in both the solution state and the film state can be applicable to the design of CP-based smart sensors, polarized materials, switching devices, etc.
UR - http://www.scopus.com/inward/record.url?scp=77957314150&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77957314150&partnerID=8YFLogxK
U2 - 10.1021/ja1067349
DO - 10.1021/ja1067349
M3 - Article
C2 - 20836560
AN - SCOPUS:77957314150
VL - 132
SP - 13928
EP - 13935
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 39
ER -