| Project/Area Number |
15350107
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Chemistry related to living body
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| Research Institution | Ritsumeikan University |
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Principal Investigator |
TAMIAKI Hitoshi Ritsumeikan University, Faculty of Science and Engineering Department of Bioscience and Biotechnology, Professor, 理工学部, 教授 (00192641)
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| Project Period (FY) |
2003 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥11,900,000 (Direct Cost: ¥11,900,000)
Fiscal Year 2006: ¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2005: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2004: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2003: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | Synthetic Chemistry / Self-Assembly / Supramolecular Chemistry / Nanomaterial / Surface and Interface Property / 超分化学 / 光合成 / 光収穫アンテナ / クロロフィル / 超分子 / 自己集積 |
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| Research Abstract |
As model chlorophylls in main light-harvesting antenna systems (chlorosomes) of green photosynthetic bacteria, coordinatable metal complexes (Mg, Zn and Cd) of cyclic tetrapyrroles possessing sterically less hindered hydroxy and hydrogen-bonded carbonyl groups were prepared by modifying naturally occurring chlorophylls and synthetic porphyrins using organic and bio-synthetic procedures. A variety of model compounds examined here self-aggregated to form large oligomers as well as natural chlorosomal chlorophylls did. The self-aggregates of synthetic molecules absorbed lights from visible to near-infrared region, which are wider than natural chlorosomes.
To elucidate the supramolecular structures of the self-aggregates, ^<18>O-labeled vibrational and ^<13>C-labeled magic angle spinning nuclear magnetic spectroscopies were examined as well as electronic and circular dichroism absorption ones, indicating that coordination of 3^1-hydroxy group to central metal, hydrogen bond of 13-carbonyl group to the coordinated OH and π-π stacking among cyclic tetrapyrroles made the self-aggregates.
Chemically and mechanically stable self-assemblies of synthetic chlorophylls were prepared using condensation of silanols (sol-gel method). The submicrometer-sized self-assemblies had the same optical properties as the self-aggregates in a homogeneous system. The capsules had negative charges on their surface in an aqueous solution as well as natural chlorosomes, and adsorbed on any positive charged surfaces. Such supramolecular systems are promising for construction of photoactive nanodevices.
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