SYNTHESIS AND HELIX-SENSE-SELECTIVE POLYMERIZATION OF CHIRAL VINYL BIPHENYL MONOMERS

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	SYNTHESIS AND HELIX-SENSE-SELECTIVE POLYMERIZATION OF CHIRAL VINYL BIPHENYL MONOMERS
	Cao Hongqing; Cui Jiaxi; Liu Anhua; Wan Xinhua
刊名	ACTA POLYMERICA SINICA
	2010-02-20
期号	2 页码:222-230
关键词	Optically Active Helical Polymer Memory Effect Radical Polymerization Atom Transfer Radical Polymerization Anionic Polymerization
ISSN号	1000-3304
英文摘要	A series of vinyl biphenyl monomers containing chiral alkoxy terminals were synthesized and polymerized via conventional radical polymerization, atom transfer radical polymerization and anionic polymerizations. Optical polarimetry and circular dichroism spectroscopy were employed to characterize the chiroptical properties of model compounds,monomers and polymers. It was found that only the monomers with chiral alkoxy phenyl located at the ortho position of vinyl group were able to yield the polymers displaying a specific optical rotation [alpha](365)(25) different obviously from their precursors and model compounds. These polymers also displayed cotton effects in the UV-Vis absorption region of biphenyl side-group, in a sharp contrast to the monomers, suggesting the formation of a chiral secondary structure of polymer backbone. For vinyl polymers, the most possible chiral structure was helical conformation of main-chain with an excess helix sense. Furthermore, the helical polymer containing chiral alkoxy group at meta-position, i.e. P3M2St, showed an [alpha](365)(25) value larger than that of monomer, while the helical polymer containing chiral alkoxy group at para-position, i.e. P4M2St, showed less intensive optical rotation than its monomer, indicating opposite helical sense of main-chain conformation. The reaction temperature and solvent were varied to study the effect of polymerization condition on the [alpha](365)(25), value of polymers. It was found that the [alpha](365)(25) value of polymers was independent on not only the polymerization condition employed but also the molecular weight of the polymer studied. The helical polymers obtained via anionic polymerization exhibited a larger difference in [alpha](365)(25), from monomer than those resultant from radical polymerization, implying that the anionic polymerization had advantage of obtaining stereoregular structure. After removal of chiral alkoxy groups, the optically active helical polymers obtained showed optical rotations even larger than their precursor polymers although no stereogenic center was presented in the molecule, suggesting somewhat "memory effect".
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000275562400015
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/69677]
专题	中国科学院化学研究所
通讯作者	Cao Hongqing
作者单位	Peking Univ, Dept Polymer Sci & Engn, Key Lab Polymer Chem & Phys,Minist Educ, Beijing Natl Lab Mol Sci,Coll Chem & Mol Engn, Beijing 100871, Peoples R China
推荐引用方式 GB/T 7714	Cao Hongqing,Cui Jiaxi,Liu Anhua,et al. SYNTHESIS AND HELIX-SENSE-SELECTIVE POLYMERIZATION OF CHIRAL VINYL BIPHENYL MONOMERS[J]. ACTA POLYMERICA SINICA,2010(2):222-230.
APA	Cao Hongqing,Cui Jiaxi,Liu Anhua,&Wan Xinhua.(2010).SYNTHESIS AND HELIX-SENSE-SELECTIVE POLYMERIZATION OF CHIRAL VINYL BIPHENYL MONOMERS.ACTA POLYMERICA SINICA(2),222-230.
MLA	Cao Hongqing,et al."SYNTHESIS AND HELIX-SENSE-SELECTIVE POLYMERIZATION OF CHIRAL VINYL BIPHENYL MONOMERS".ACTA POLYMERICA SINICA .2(2010):222-230.