2002 Fiscal Year Final Research Report Summary
Precision Synthesis of Poly(thiophene)s by oxidative polymerization
| Project/Area Number |
13450384
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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 |
高分子合成
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| Research Institution | Waseda University |
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Principal Investigator |
NISHIDE Hideyuki Waseda University, School of Science and Engineering, Professor, 理工学部, 教授 (90120930)
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| Co-Investigator(Kenkyū-buntansha) |
OYAIZU Kenichi Waseda University, Advanced Research Institute for Science and Engineering, Assistant Professor, 理工学総合研究センター, 講師 (90277822)
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| Project Period (FY) |
2001 – 2002
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| Keywords | oxidative polymerization / thiophene / conjugated polymer / poly (phenyleneoxide) / poly (phenylene) / helical polymer / phenoxy radical / depolymerization |
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| Research Abstract |
Alkyl-sulfinyl substituted poly(l,2-phenyleneoxide) and poly(1,3-phenylene) are prepared by oxidative polymerization under air to lead them the double-stranded structure via oxidation and superacid-induced intraraolecular condensation. The extended π-conjugation system of the result polymers is also discussed. Additionally, a depolymerization of the polymers consisted of alkylsulfinyl phenols are revealed and applied to the control of molecular weight.
(1) Synthesis of the helical polymer consisted of condensed thiophene rings. A oxidative polymerization of 4-methoxy-2-methylsulfinylphenol afforded the precursor poly(1,2-phenyleneoxide) with pendant methylsulfinyl groips. The following intramolecular condensation gave the phenoxathiinium-type helical ladder polymer. The absorption maximum and tail in the UV-vis spectrum of the ladder polymer showed bathochromicalfy shift comprable with those of the precursor polymer to suggest the extended π-conjugated planarity even in the helical stru
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cture. A Pd catalyzed polymerization of 1,3-benzene bis(boronate) and methylthio substituted 1,3-dibromobenzene provided the corresponding poly(1,3-phenylene). The oxidation and the intramolecular condensation of the pendant groups were carried out to yield the helical ladder polymer. The stricture was characterized by NMR, IR and Elemental analysis, the absorption spectrun revealed the delocalization of the π-electron.
(2) Study of the polymerization and depolymerization kinetics. In order to control the nolecular weight of the poly (alkylsulfinyl-phenyleneoxide), the condition of depolymerization of poly (2,6-dimethyl-1,4-phenyleneoxide) (PPO) was studied. An addition of 2,6-dimethylphenol and evaluated phenoxy-radicals in the oxidative condition shifted the equilibrium to the depolymerization of the polymer. The molecular weight after the depolymerization depended on the concentration of the terminal OH groups and agreed with the theoretical calculated molecular weight. A presence of the intermediate phenoxy-radical in the ESR and the rate constants from UV-vis spetra indicated the depolymerization of polyfphenyleneoxide) was occurred by the repetitive redistribution. Less
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