Correlation between the molecular structure and transcis isomerization characteristics of azobenzenes

被引：0

作者：

HAN Mina ^{[1
]}

HONDA Takumu ^{[1
]}

机构：

[1] Department of Chemistry and Department of Electronic Chemistry,Tokyo Institute of Technology

来源：

Science China(Chemistry) | 2011年 / 12期

关键词：

azobenzene; isomerization; lifetime of cis form; molecular structure;

D O I：

暂无

中图分类号：

O621.13 [];

学科分类号：

070303 ; 081704 ;

摘要：

Photochemical and thermal isomerization of various azobenzenes was systematically investigated to understand the correlation between the molecular structure and trans ? cis isomerization characteristics of azobenzenes.A blue shift in πDπ* absorption band of ortho-alkylated azobenzenes(1o and 2o) was observed together with a reduction in molar extinction coefficient in comparison with both meta-alkylated azobenzenes(4m and 5m) and 7p lacking the meta and ortho substituents.For ortho-alkylated azobenzene,photochemical trans-to-cis isomerization and thermal back cis-to-trans isomerization in solution occurred slowly when compared with 4m,5m and 7p.The half-life time of the cis form of 2o was found to be 380 h,which is about 8-50 times longer than those of comparable 4m,5m(43-13 h) and 7p(7 h).Furthermore,comparison of the molecular structure and isomerization characteristics of azobenzene thiol(2o and 5m) self-assembled monolayers on flat gold surfaces indicates that the trans-to-cis photoconversion in monolayer systems is influenced by steric hindrance and strong intermolecular interaction between azobenzene units.

引用

页码：1955 / 1961

页数：7