2007 Fiscal Year Final Research Report Summary
Studies on Complex Formation Mechanisms of Chitosan Based on Synchrotron Fiber Diffication
| Project/Area Number |
18550104
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Polymer chemistry
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
NOGUCHI Keiichi Tokyo University of Agriculture and Technology, Instrumentation Analysis Center, Associate Professor (00251588)
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| Project Period (FY) |
2006 – 2007
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| Keywords | X-ray Diffraction / Crystal Structure / Synchrotron Radiation / Interaction / Hydrogen Bond / Polysaccharide / Chitosan / Fiber Diffraction |
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| Research Abstract |
In order to elucidate the intermolecular interactions involved in complex formation of chitosan with hydrogen halides, crystal structures of chitosan complexes with HBr and HI were analyzed based on synchrotron X-ray fiber diffraction data (BL40B2, SPring-8, Hyogo, Japan). Both crystals are isomorphous and belong to the monoclinic space group P2_1. The unit cell constants are a=9.299(9), b=9.504(8), c(fiber axis)=10.41(1) A and β= 106.93(8)°, and a=9.46(2), b=9.79(2), c(fiber axis)=10.33(2) A and β=105.1(2)° for HBr and HI complexes, respectively. The final packing models were obtained by the linked-atom least-squares refinement, which gave R-factors of 0.192 for HBr complex (93 observed spots) and 0.193 for HI complex (44 observed spots). The halide ions are aligned along the c-axis at intervals of about 5A and are surrounded by four polymer chains. In an asymmetric unit, there are two halide ions. One ion accepts three hydrogen bonds from NH3^+ groups (N2 nitrogen). The other one participates in one hydrogen bond from N2 and two hydrogen bonds from primary hydroxyl groups (O6 oxygen). In addition, the chitosan chains are linked by N-H…O and C-H…O hydrogen bonds along the b-axis direction. The crystal structure of the hydrated form of chitosan was reanalyzed using synchrotron X-ray fiber diffraction data (BL38B1, Spring-8). The chitosan chains make sheet structures parallel to the bc-plane and these sheets stack along the a-axis. Water molecules form columns between these sheets. The sites of the halide ions in the complex crystals are similar to those of the water molecules in the hydrated form. It was suggested that the columnar structure of water in the hydrated form plays an important role for the complex formation.
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[Journal Article] Crystal Structures of Chitosan/Hydrogen Halides Complexes Based on Synchrotron X-ray Fiber Diffraction2006
Author(s)
Keiichi, Noguchi, Masakazu, Kanenari, Amornrat, Lertworasirikul, Shingo, Yokoyama, Kenji, Okuyama, Kozo, Ogawa
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Journal Title
Advances in Chitin Science and Technology
Pages: 41-43
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] 1,6,11,16-tetraoxacycloeicosane-7,10,17,20-tetraone2006
Author(s)
Keiichi, Noguchi, Hidekazu, Kondo, Yasushi, Ichikawa, Junichiro, Washiyama, Kenji, Okuyama
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Journal Title
Acta Clystallogr C62
Pages: 528-30
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Crystal Structures of Chitosan/Hydrogen Halides Complexes Based on Synchrotron X-ray Fiber Diffraction2006
Author(s)
Keiichi, Noguchi, Masakazu, Kanenari, Amornrat, Lertworasirikul, Shingo, Yokoyama, Kenji, Okuyama, Kozo, Ogawa
Organizer
7th Asia-Pacific Chitin and Chitosan Symposium(APCCS)
Place of Presentation
Busan, Korea
Year and Date
20060423-26
Description
「研究成果報告書概要(欧文)」より
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