Solvent and temperature effects on the chiral aggregation of poly(alkylarylsilane)s bearing remote chiral groups

被引:105
作者
Nakashima, H
Fujiki, M
Koe, JR
Motonaga, M
机构
[1] Nippon Telegraph & Tel Corp, Nippon Telegraph & Telephone Corp, Basic Res Labs, Kanagawa 2430198, Japan
[2] JST, Japan Sci & Technol Corp, CREST, Kawagoe, Saitama 3320012, Japan
关键词
D O I
10.1021/ja000869h
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Novel switchable chiroptical characteristics of poly(alkylarylsilane) microaggregates; controllable by the choice of good/poor solvent ratio (solvent polarity), solvent addition order, and Sample temperature are described. The formation of stable chiral aggregates depends critically on the polysilane structure and stereochemistry. Poly[n-hexyl-(p-(S)-2-methylbutoxyphenyl)silane] (1), optically inactive in molecularly dispersed THF solution due to the existence of dynamically equivalent amounts of right (P)- and left (M)-handed screw sense helical main chain domains, shows a marked bisignate CD signal due to the formation of chiral aggregates in good/poor cosolvent systems. The sign and magnitude of the CD signals are dependent on solvent polarity, solvent addition order, and thermal effects. The less sterically hindered poly[methyl-(p-(S)2-methylbutoxyphenyl)silane] (2) exhibits a weak, bisignate, nonswitchable CD signal in only the toluene/ acetonitrile system, and no CD signals are evident in pure toluene or THF due to masking of the helicity. In contrast, although the even less sterically hindered, less polar poly[methyl-(m-(S)-2-methylbutoxyphenyl) silane] (3) does show optical activity in pure THF or toluene (negative CD signal at 310 nm), the CD signal disappears on formation of aggregates in good/poor cosolvent systems.
引用
收藏
页码:1963 / 1969
页数:7
相关论文
共 73 条
[1]   CHIROPTICAL SWITCH BASED ON PHOTOISOMERIZATION OF BILIRUBIN-III-ALPHA BOUND TO HUMAN SERUM-ALBUMIN [J].
AGATI, G ;
MCDONAGH, AF .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1995, 117 (15) :4425-4426
[2]   Helical polyacetylene synthesized with a chiral nematic reaction field [J].
Akagi, K ;
Piao, G ;
Kaneko, S ;
Sakamaki, K ;
Shirakawa, H ;
Kyotani, M .
SCIENCE, 1998, 282 (5394) :1683-1686
[3]  
[Anonymous], ANGEW CHEM INT ED
[4]  
[Anonymous], ANGEW CHEM INT ED
[5]   Chirality in regioregular and soluble polythiophene: An internal probe of conformational changes induced by minute solvation variation [J].
Bidan, G ;
Guillerez, S ;
Sorokin, V .
ADVANCED MATERIALS, 1996, 8 (02) :157-&
[6]   Chirality inversion in a molecular exciton [J].
Boiadjiev, SE ;
Lightner, DA .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2000, 122 (02) :378-383
[7]   Temperature effect on supramolecular chirality induction in bis(zinc porphyrin) [J].
Borovkov, VV ;
Lintuluoto, JM ;
Fujiki, M ;
Inoue, Y .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2000, 122 (18) :4403-4407
[8]   STEREOMUTATION IN OPTICALLY-ACTIVE REGIOREGULAR POLYTHIOPHENES [J].
BOUMAN, MM ;
MEIJER, EW .
ADVANCED MATERIALS, 1995, 7 (04) :385-387
[9]   Transfer of chiral information through molecular assembly [J].
Castellano, RK ;
Nuckolls, C ;
Rebek, J .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1999, 121 (48) :11156-11163
[10]  
Cheon KS, 2000, ANGEW CHEM INT EDIT, V39, P1482, DOI 10.1002/(SICI)1521-3773(20000417)39:8<1482::AID-ANIE1482>3.0.CO