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Published on: November 12, 2013
Computing handedness: quantized and superposed switch and dynamic memory of helical polysilylene
M Fujiki1, J R Koe, M Motonaga
1NTT Basic Research Laboratories, 3-1 Wakamiya, Morinosato, Atsugi, Kanagawa 243-0198, Japan.
Journal of the American Chemical Society
|June 28, 2001
Summary
Two novel helical polymers exhibit switchable helicity, enabling molecular recognition and potential use as information processors. One polymer shows temperature-dependent helical switching, while the other remains stable, offering insights into polymer dynamics.
Area of Science:
- Polymer Chemistry
- Materials Science
- Supramolecular Chemistry
Background:
- Development of advanced polymers with tunable properties is crucial for novel applications.
- Chiral polymers offer unique functionalities due to their helical structures.
- Understanding the relationship between polymer structure and dynamic behavior is key to designing responsive materials.
Purpose of the Study:
- To synthesize and characterize two new conjugating helical polymers with silicon backbones and chiral pendants.
- To investigate the temperature-dependent helical switching behavior and molecular recognition capabilities of these polymers.
- To explore the potential of these polymers as molecular information processors.
Main Methods:
- Synthesis of poly[(R)-3,7-dimethyloctyl-(S)-3-methylpentylsilylene] (PS-1) and its diastereomer poly[(S)-3,7-dimethyloctyl-(S)-3-methylpentylsilylene] (PS-2).
- Molecular mechanics calculations to predict helical structures and energy landscapes.
- Experimental investigation of helical switching using thermal energy bias in dilute isooctane.
Main Results:
- PS-1 demonstrated switchable ambidextrous helicity across three distinct temperature regions, attributed to superposed P- and M-helicities undergoing dynamic pseudo-racemization.
- PS-1 exhibited molecular recognition ability and dynamic memory function in region 2, sensitive to solvent properties.
- PS-2 did not exhibit preferential screw-sense switching within the tested temperature range (-80 to +80 degrees C).
Conclusions:
- The synthesized helical polymers possess unique temperature-dependent switching properties.
- PS-1's dynamic helical behavior enables molecular recognition and suggests potential as a molecular information processor.
- The difference in switching behavior between PS-1 and PS-2 highlights the influence of subtle structural variations on polymer dynamics.
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