1997 Fiscal Year Final Research Report Summary
PREPARATION OF POLYMERS WITH SECONDARY STRUCTURES SPONTANEOUSLY REGULATED BY HYDROGEN BONDING AMONG SIDE CHAINS AND THEIR APPLICATION AS MOLECULAR DEVICES
| Project/Area Number |
08651045
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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 |
高分子合成
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| Research Institution | CHIBA UNIVERSITY |
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Principal Investigator |
NAKAHIRA Takayuki CHIBA UNIVERSITY,FACULTY OF ENGINEERING,APPLIED CHEMISTRY,PROFESSOR, 工学部, 教授 (30009740)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Poly (methacrylamide) / Poly (glutamine) / amide hydrogen bonding / chromophore orientation / molecular device / excitation energy transport |
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| Research Abstract |
Poly (methacrylamide) s with regulated primary structures, i.e., main-chain tacticity and side-chain structure, were prepared by amidation of the side-chain carboxyl groups of isotactic poly (methacrylic acid) with aromatic amines. Hydrogen bonding among the side-chain amide groups and side-chain chromophore orientation were subsequently examined. Isotactic poly (methacrylamide) having (S) -1-phenylethyl groups in the side chains was found to form intramolecular hydrogen bonding more extensively than those having (S) -1- (1-naphthyl) ethyl and other side-chain groups, showing adequate steric effects in the former in stabilizing the fully-hydrogen-bonded structure. Molecular mechanics calculations suggest that the isotactic poly (methacrylamide) s with side-chain groups of S-configuration assume right-handed 5_2 helices. The efficiency of excitation energy transport among the side chains was found to improve markedly when the poly (methacrylamide) s assume fully-hydrogen-bonded structur
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es. These polymers were found to form lamellar structures in films.
Poly (L-glutamine) s were found to assume side-chain secondary structures with chromophores oriented along the helical main chain when (S) -1- (1-naphthyl) ethyl groups and others having adequate steric hindrances are introduced in the side chains. Fluorescence quenching experiments showed that excitation energy is transported efficiently through these oriented chromophores. Circular dichroic spectra of films prepared from these polymers showed that there are three types of side-chain structures with varying chromophore orientation. Molecular mechanics calculations suggest there are several stable or quasi-stable side-chain structures, and in one of them hydrogen bonding occurs between the main chain and the side chain in accord with the IR observation that side-chain amide groups are extensively hydrogen-bonded. It is also suggested that such hydrogen bonds cause deviation of the main-chain conformation from alpha-helix. Introduction of anisotropy to these films are now being attempted.
As described above, the usefulness of isotactic poly (methacrylamide) s and poly (L-glutamine) s as molecular devices is now established. Their excitation energy transport and charge transport functions are now being investigated further by introducing such chromophores as pyrene and ferrocene in the side groups. Less
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Research Products
(4 results)
