Remarkable Effects of Terminal Groups and Solvents on Helical Folding of o-Phenylene Oligomers

被引：64

作者：

Ando, Shinji ^{[1
]}

Ohta, Eisuke ^{[1
]}

Kosaka, Atsuko ^{[1
]}

Hashizume, Daisuke ^{[1
]}

Koshino, Hiroyuki ^{[1
]}

Fukushima, Takanori ^{[1
,2
]}

Aida, Takuzo ^{[1
,3
]}

机构：

[1] RIKEN Adv Sci Inst, Wako, Saitama 3510198, Japan

[2] Tokyo Inst Technol, Chem Resources Lab, Midori Ku, Yokohama, Kanagawa 2268503, Japan

[3] Univ Tokyo, Sch Engn, Bunkyo Ku, Tokyo 1138656, Japan

来源：

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY | 2012年 / 134卷 / 27期

关键词：

CIRCULAR-DICHROISM; INVERSION; HELICENES; POLYMERS; BEHAVIOR;

D O I：

10.1021/ja303117z

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Although o-phenylene oligomers (OPnR) made of dimethoxyphenylene units are thought to be intrinsically dynamic due to pi-electronic repulsion, we show that they fold into a regular helical geometry in CH3CN when they carry terminal groups such as CH3, CH2OH, Br, CO2Bn, and NO2. We evaluated their helical inversion kinetics via optical resolution of long-chain oligomers (e.g. 16- and 24-mers) by chiral HPLC. OP24Br at 298 K shows a half-life for the optical activity of 5.5 h in CH3OH/water (7/3 v/v) and requires 34 h for complete racemization. The perfectly folded helical conformers of OPnR, unlike their imperfectly folded ones, are devoid of extended pi-conjugation and show a cyclic voltammogram featuring reversible multistep oxidation waves.

引用

页码：11084 / 11087

页数：4

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