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209 results on '"Nakamura, Naotake"'

2. Interplay of the main chain, chiral side chains, and solvent in conformational transitions: Poly{[(R)-3,7-dimethyloctyl]-[(S)-3-methylpentyl]silylene}

Author

Teramoto, Akio, Fujiki, Michiya, Terao, Ken, Terao, Yoshimi, Nakamura, Naotake, and Sato, Takahiro

Subjects
Absorption spectra -- Research, Absorption spectra -- Analysis, Light scattering -- Usage, Chemistry
Abstract

The poly{[(R)-3,7-dimethyloctyl]-[(S)-3-methylpentyl]silylene}(PRS) is studied in dilute solution by light scattering, sedimentation equilibrium, viscosity and circular dichroism. Detailed features of UV absorption spectra at different temperatures and molecular weights are presented

Published
2001

7. Stiffness of polysilylenes depending remarkably on a subtle difference in chiral side chain structure: Poly{n-hexyl-[(S)-2-methylbutyl]silylene)} and poly{n-hexyl-[(S)-3-methylpentyl]silylene}

Author

Terao, Ken, Terao, Yoshimi, Teramoto, Akio, Nakamura, Naotake, Terakawa, Ikuyo, Sato, Takahiro, and Fujiki, Michiya

Abstract

Terao K., Terao Y., Teramoto A., et al. Stiffness of polysilylenes depending remarkably on a subtle difference in chiral side chain structure: Poly{n-hexyl-[(S)-2-methylbutyl]silylene)} and poly{n-hexyl-[(S)-3-methylpentyl]silylene}. Macromolecules, 34(8), 2682-2685, March 16, 2001. Copyright © 2001, American Chemical Society. https://doi.org/10.1021/ma002030s., Light scattering and viscosity measurements were made on fractionated samples of poly- (n-hexyl-{(S)-2-methylbutyl]silylene)} (PH2MBS, 1) and poly{n-hexyl-[(S)-3-methylpentyl]silylene} (PH3MPS, 2) in isooctane to determine their stiffness, which are expressed in terms of the persistence length q of Kraty and Porod. The q of polymer 1 is as large as 85 nm and depends only slightly on temperature, indicating that its conformation is almost rodlike, whereas the q of polymer 2 is 6.2 nm, its global conformation being close to a random coil. It is concluded that the global conformation of polysilylene is determined by its side chain; polysilylene with a β-branch is much stiffer compared to those without it.

Published
2001

8. Anomalous metallic-like transport of Co–Pd ferromagnetic nanoparticles cross-linked with π-conjugated molecules having a rotational degree of freedom

Author

Ito, Yoshikazu, primary, Takai, Kazuyuki, additional, Miyazaki, Akira, additional, Sivamurugan, Vajiravelu, additional, Kiguchi, Manabu, additional, Ogawa, Yoshihiro, additional, Nakamura, Naotake, additional, Valiyaveettil, Suresh, additional, Tada, Tomofumi, additional, Watanabe, Satoshi, additional, and Enoki, Toshiaki, additional

Published
2014
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12. Magnetic Sponge Prepared with an Alkanedithiol-Bridged Network of Nanomagnets

Author

Ito, Yoshikazu, primary, Miyazaki, Akira, additional, Takai, Kazuyuki, additional, Sivamurugan, Vajiravelu, additional, Maeno, Takashi, additional, Kadono, Takeshi, additional, Kitano, Masaaki, additional, Ogawa, Yoshihiro, additional, Nakamura, Naotake, additional, Hara, Michikazu, additional, Valiyaveettil, Suresh, additional, and Enoki, Toshiaki, additional

Published
2011
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20. Temperature and solvent dependence of stiffness of poly{n-hexyl-[(s)-3-methylpentyl]silylene} in dilute solutions

Author

Terao, Ken, Terao, Yoshimi, Teramoto, Akio, Nakamura, Naotake, Fujiki, Michiya, Sato, Takahiro, Terao, Ken, Terao, Yoshimi, Teramoto, Akio, Nakamura, Naotake, Fujiki, Michiya, and Sato, Takahiro

Abstract

Terao K., Terao Y., Teramoto A., et al. Temperature and solvent dependence of stiffness of poly{n-hexyl-[(s)-3-methylpentyl]silylene} in dilute solutions. Macromolecules, 34(13), 4519-4525, May 25, 2001. Copyright © 2001, American Chemical Society. https://doi.org/10.1021/ma010212w.

Published
2001

21. Conformational transitions in poly{n-hexyl-[(S)-3-methylpentyl]silylene) in dilute solution: Temperature and molecular weight dependence detected by circular dichroism

Author

1000060334132, Terao, Ken, Terao, Yoshimi, Teramoto, Akio, 1000010066722, Nakamura, Naotake, Fujiki, Michiya, 1000010196248, Sato, Takahiro, 1000060334132, Terao, Ken, Terao, Yoshimi, Teramoto, Akio, 1000010066722, Nakamura, Naotake, Fujiki, Michiya, 1000010196248, and Sato, Takahiro

Abstract

Terao K., Terao Y., Teramoto A., et al. Conformational transitions in poly{n-hexyl-[(S)-3-methylpentyl]silylene) in dilute solution: Temperature and molecular weight dependence detected by circular dichroism. Macromolecules, 34(18), 6519-6525, July 24, 2001. Copyright © 2001, American Chemical Society. https://doi.org/10.1021/ma0104433., Ten narrow-distribution samples of poly{n-hexyl-[(S)-3-methylpentyl]silylene} (PH3MPS) ranging in weight-average molecular weight from 3.1 × 103 to 8.7 × 105 in isooctane, n-hexane, and methylcyclohexane were studied by circular dichroism and ultraviolet absorption over a wide temperature range (from -75 to 85 °C). To follow the conformational transition, Kuhn's dissymmetry factor gabs as a measure of helicity was determined as a function of molecular weight and temperature from the ratio of circular dichroism to absorbency. The molecular weight dependence of gabs was analyzed by a statistical mechanical theory based on a conformational picture of an alternating sequence of right-handed and left-handed helices intervened by helix reversals. The free energy of the helix reversal was much smaller than those for polyisocyanates investigated previously [poly((R)-1-deuterio-n-hexyl isocyanate) and poly-((R)-2-deuterio-n-hexyl isocyanate)] at the same temperatures although its solutions showed large circular dichroism. Therefore, it was shown that the correlation lengths of the helix for this polymer were much shorter than the polyisocyanates at the same temperature. Thus, the helix reversal is the dominant molecular process in the conformational properties of PH3MPS.

Published
2001

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